exactmatch =
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There are 6929 matches found
| Name | BBrefID | Year | Span | Games | Team | League | Location |
| Ed Abbaticchio | abbati001edw | 1904 | Boston | National League | Boston, MA | ||
| Doc Abbott | abbott001cha | 1904 | 76 g. | Coshocton OH | Independent | , | |
| Doc Abbott | abbott001cha | 1904 | Lancaster OH | Independent | , | ||
| Fred Abbott | abbott002har | 1904 | 41 g. | Cleveland | American League | Cleveland, OH | |
| Fred Abbott | abbott002har | 1904 | 8/12-9/20 | Columbus Senators | American Association | , | |
| Spencer Abbott | abbott001spe | 1904 | 113 g. | Topeka Saints | Missouri Valley League | , | |
| Spencer Abbott | abbott001spe | 1904 | Pittsburg Coal Diggers | Missouri Valley League | , | ||
| Harry Ables | ables-001har | 1904 | Southwestern Univ | College | , | ||
| Harry Ables | ables-001har | 1904 | 1 g. postseason | Corsicana Oil Citys | Texas League | , | |
| Harry Ables | ables-001har | 1904 | 9/9 | Memphis Egyptians | Southern Association | , | |
| Harry Ables | ables-001har | 1904 | 9/16-9/23 | Shreveport Pirates | Southern Association | , | |
| Bill Abstein | abstei001wil | 1904 | 4/30-9/2 | Houston Wanderers | South Texas League | , | |
| Victor Accorsini | accors001vic | 1904 | 36 g. | Norwich Reds | Connecticut State League | , | |
| Victor Accorsini | accors001vic | 1904 | 7/4-9/21 | Nashville Volunteers | Southern Association | , | |
| Adams | adams-102--- | 1904 | Univ. Nebraska | College | , | ||
| Adams | adams-079--- | 1904 | 7/13-7/14 | Grand Rapids Orphans | Central League | , | |
| E. Adams | adams-001e-- | 1904 | +7/-9/5 | Burlington River Rats | Iowa League | , | |
| H. S. Adams | 1904 | no g. | Evansville River Rats | Central League | , | ||
| Harry Adams | adams-006har | 1904 | 5/2-9/4 | Guthrie Blues | Southwestern League | , | |
| Joe Adams | adams-003jos | 1904 | Mattoon IL | Independent | , | ||
| Milton Adams | adams-001cly | 1904 | Greenville Cotton Pickers | Cotton States League | , | ||
| Rick Adams | adams-001reu | 1904 | 5/1-9/28 | Montreal Royals | Eastern League | , | |
| Theodore Adams | adams-001the | 1904 | , | ||||
| William Adams | 1904 | U. CA-Berkeley | College | , | |||
| Merle Adkins | adkins001mer | 1904 | 4/29-9/21 | Baltimore Orioles | Eastern League | , | |
| Bert Adrian | adrian001ber | 1904 | 4/30-7/21+ | San Antonio Bronchos | South Texas League | , | |
| Bert Adrian | adrian001ber | 1904 | +7/31+ | 72 g. | Beaumont Millionaires | South Texas League | , |
| Joe Agan | agan--001jos | 1904 | 10 g. | Fort Scott Giants | Missouri Valley League | , | |
| Pete Agnew | agnew-001pet | 1904 | 5/1-9/30 | Harrisburg Senators | Tri-State League | , | |
| Walter Ahearn | ahearn001wal | 1904 | 18 g. | New Haven Blues | Connecticut State League | , | |
| Walter Ahearn | ahearn001wal | 1904 | Meriden Silverites | Connecticut State League | , | ||
| Alvia Ahlin | ahlin-001a-- | 1904 | 5/12-8/18 | Keokuk Indians | Iowa League | , | |
| Alvia Ahlin | ahlin-001a-- | 1904 | Des Moines Prohibitionists | Western League | , | ||
| Dad Ahorn | ahorn-001a-- | 1904 | 5/3 | San Antonio Bronchos | South Texas League | , | |
| Dad Ahorn | ahorn-001a-- | 1904 | 5/25-6/10 | Oklahoma City Mets | Southwestern League | , | |
| Dad Ahorn | ahorn-001a-- | 1904 | Muskegon IT | Independent | , | ||
| Dad Ahorn | ahorn-001a-- | 1904 | 8/29-9/03 | Shawnee Browns/Chickasha Indians | Southwestern League | , | |
| Dad Ahorn | ahorn-001a-- | 1904 | 9/11-9/27 | Enid Evangelists | Southwestern League | , | |
| Raleigh Aitchison | aitchi001ral | 1904 | 5 g. | Leavenworth Orioles | Missouri Valley League | , | |
| Abe Akers | akers-001abe | 1904 | 91 g. | Columbia Skyscrapers | South Atlantic League | , | |
| Lee Akers | akers-001jak | 1904 | 4/26-5/14 | Colorado Springs Millionaires | Western League | , | |
| Lee Akers | akers-001jak | 1904 | 5/28-8/20 | Knoxville | Tennessee-Alabama League | , | |
| Roy Akin | akin--001roy | 1904 | 4/30-9/2 | Galveston Sand Crabs | South Texas League | , | |
| Roy Akin | akin--001roy | 1904 | 9/7-9/20 | Kansas City Blues | American Association | , | |
| Alberts | 1904 | +6/19+ | Carrington ND | Independent | , | ||
| Alberts | albert015--- | 1904 | 8/18-9/5 | Burlington River Rats | Iowa League | , | |
| Bobby Alberts | albert002rob | 1904 | 5/7-7/24+ | Waterloo Microbes | Iowa League | , | |
| Bobby Alberts | albert002rob | 1904 | 8/5-9/5 | Marshalltown Grays | Iowa League | , | |
| Charles Alberts | 1904 | Harbor Springs MI | Independent | , | |||
| Cy Alberts | albert001fre | 1904 | 4/28-9/10 | Fort Wayne Railroaders | Central League | , | |
| Gus Alberts | albert001gus | 1904 | 13 g. | Topeka Saints | Missouri Valley League | , | |
| Gus Alberts | albert001gus | 1904 | Umpire | Missouri Valley League | , | ||
| A. J. Albertson | albert015--- | 1904 | 5/7-5/17+ | Burlington River Rats | Iowa League | , | |
| Bill Alexander | alexan005wil | 1904 | 4/30-5/2 | San Antonio Bronchos | South Texas League | , | |
| Bill Alexander | alexan005wil | 1904 | 5/7-9/24 | Shreveport Pirates | Southern Association | , | |
| George Alexander | 1904 | Binghamton Bingoes | New York State League | , | |||
| Hillary Alexander | alexan001h-- | 1904 | 28+ g. | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |
| Harry Allemang | allema001har | 1904 | 4/27-9/18 | Indianapolis Indians | American Association | , | |
| Allen | allen-058--- | 1904 | 5/11-6/7 | Manchester | New England League | , | |
| Allen | 1904 | Oklahoma City Mets | Southwestern League | , | |||
| Dick Allen | allen-002dic | 1904 | 7/20 | Harrisburg Senators | Tri-State League | , | |
| Edward Allen | allen-001f-- | 1904 | -9/11 | Enid Evangelists | Southwestern League | , | |
| Peter Allen | 1904 | 7 g. | Bridgeport Orators | Connecticut State League | , | ||
| Hank Allis | allis-001han | 1904 | +5/18-5/30+ | Waterloo Microbes | Iowa League | , | |
| Arthur Alloway | allowa001art | 1904 | 5/18-7/26 | Birmingham Barons | Southern Association | , | |
| Arthur Alloway | allowa001art | 1904 | Jackson | , | |||
| Peter Allyn | allyn-001pet | 1904 | San Francisco | California State League | , | ||
| Peter Allyn | allyn-001pet | 1904 | San Jose | California State League | , | ||
| Martin Almquist | 1904 | Marquette KS | Independent | , | |||
| Whitey Alpermann | alperm001cha | 1904 | 121 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Dave Altizer | altize001dav | 1904 | 107 g. | Meriden Silverites | Connecticut State League | , | |
| Dave Altizer | altize001dav | 1904 | Springfield Ponies | Connecticut State League | , | ||
| Joseph Altman | altman001jos | 1904 | Snohomish WA | Independent | , | ||
| Ambrose | ambros004--- | 1904 | 5/7-5/14+ | Burlington River Rats | Iowa League | , | |
| Red Ames | ames--002leo | 1904 | New York | National League | New York, NY | ||
| Doc Amole | amole-001doc | 1904 | 5/1-8/7 | Providence Grays | Eastern League | , | |
| Doc Amole | amole-001doc | 1904 | 8/16-9/16 | New Bedford Whalers | New England League | , | |
| Charles Anderberg | anderb001cha | 1904 | no g. | Rochester Bronchos | Eastern League | , | |
| Charles Anderberg | anderb001cha | 1904 | 5/13 | Fall River Indians | New England League | , | |
| Anderson | anders025--- | 1904 | 5/6-5/18+ | Oskaloosa Quakers | Iowa League | , | |
| Anderson | anders025--- | 1904 | 6/-9/5 | Boone Coal Miners | Iowa League | , | |
| Anderson | anders082--- | 1904 | 1 g. | Tacoma Tigers | Pacific Coast League | , | |
| Andy Anderson | anders003and | 1904 | 204 g. | San Francisco Seals | Pacific Coast League | , | |
| Andy Anderson | anders003and | 1904 | 9/19-9/21 | New Orleans Pelicans | Southern Association | , | |
| Andy Anderson | anders003art | 1904 | Portland Browns | Pacific Coast League | , | ||
| Andy Anderson | anders003art | 1904 | 4/23-9/24 | Little Rock Travelers | Southern Association | , | |
| Byron Anderson | anders026--- | 1904 | 7/2-7/31 | Sioux City Soos | Western League | , | |
| Byron Anderson | anders026--- | 1904 | 8/5-8/27 | Colorado Springs Millionaires | Western League | , | |
| Edward Anderson | 1904 | Dallas Giants | Texas League | , | |||
| Frank Anderson | 1904 | U. Georgia | College | , | |||
| Goat Anderson | anders003edw | 1904 | 4/28-9/11 | South Bend Greens | Central League | , | |
| J. W. Anderson | anders001ant | 1904 | 4/27-5/29 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| J. W. Anderson | anders001ant | 1904 | 8/9-8/12 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| John Anderson | anders010joh | 1904 | 143 g. | New York | American League | New York, NY | |
| Marvin Anderson | anders007mar | 1904 | -9/10 | 115 g. | New Haven Blues | Connecticut State League | , |
| Ollie Anderson | anders001oll | 1904 | Umpire | Northern League | , | ||
| Smylie Anderson | anders001s-- | 1904 | 44+ g. | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |
| Spike Anderson | anders003a-- | 1904 | Hamline Univ. | College | , | ||
| Spike Anderson | anders003a-- | 1904 | 5/19- | 51 g. | Superior Longshoremen | Northern League | , |
| Spike Anderson | anders003a-- | 1904 | 7/1-8/8+ | Burlington River Rats | Iowa League | , | |
| Tom Anderson | anders000tom | 1904 | +8/13-8/25 | Enid Evangelists | Southwestern League | , | |
| George Andreas | andrea002geo | 1904 | 4/27-8/15 | Dallas Giants | Texas League | , | |
| Butch Andrews | 1904 | Shawnee Browns/Chickasha Indians | Southwestern League | , | |||
| Charles Andrews | andrew001cha | 1904 | 4/29-8/8 | South Bend Greens | Central League | , | |
| Charles Andrews | andrew001cha | 1904 | 8/9-8/14 | Wheeling Stogies | Central League | , | |
| Charles Andrews | andrew001cha | 1904 | 8/15-9/11 | South Bend Greens | Central League | , | |
| Doc Andrews | andrew001jay | 1904 | 4/24-6/20 | Sioux City Soos | Western League | , | |
| Doc Andrews | andrew001jay | 1904 | 6/22-9/2 | Nashville Volunteers | Southern Association | , | |
| Nat Andrews | 1904 | Wellsville NY | Independent | , | |||
| Ernest Anklam | anklam001ern | 1904 | +5/1-6/4+ | 29 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , |
| Ernest Anklam | anklam001ern | 1904 | +6/10-9/5 | Waterloo Microbes | Iowa League | , | |
| Bill Annis | annis-001wil | 1904 | 5/19- | 48 g. | Winnipeg Maroons | Northern League | , |
| Bill Annis | annis-001wil | 1904 | 20 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Bill Annis | annis-001wil | 1904 | Rock Island Islanders | Illinois-Indiana-Iowa League | , | ||
| Samuel Apperious | apperi001wil | 1904 | Montpelier-Barre | Northern New York League | , | ||
| Fred Applegate | appleg002fre | 1904 | 4/30-9/26 | Toronto Maple Leafs | Eastern League | , | |
| Fred Applegate | appleg002fre | 1904 | 9/30-10/10 | Philadelphia | American League | Philadelphia, PA | |
| Cleveland Arbogast | arboga001cle | 1904 | 4/30-8/2 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Cleveland Arbogast | arboga001cle | 1904 | 8/8-8/15 | Fort Worth Panthers | Texas League | , | |
| Jimmy Archer | archer001jam | 1904 | 6/6-8/9+ | Boone Coal Miners | Iowa League | , | |
| Jimmy Archer | archer001jam | 1904 | 9/6- | 7 g. | Pittsburgh | National League | Pittsburgh, PA |
| Chauncy Archiquette | archiq001c-- | 1904 | 59 g. | Leavenworth Orioles | Missouri Valley League | , | |
| Chauncy Archiquette | archiq001c-- | 1904 | 7/12- | Topeka Saints | Missouri Valley League | , | |
| Chauncy Archiquette | archiq001c-- | 1904 | Haskell Institute | School | , | ||
| Frank Arellanes | arella001fra | 1904 | San Jose | California State League | , | ||
| Joseph Arlington | arling001jos | 1904 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | ||
| Joseph Arlington | arling001jos | 1904 | Holyoke Paperweights | Connecticut State League | , | ||
| Joseph Arlington | arling001jos | 1904 | Kingston Colonials | Hudson River League | , | ||
| Joseph Arlington | arling001jos | 1904 | 7/28-9/18 | Syracuse Stars | New York State League | , | |
| Charlie Armbruster | armbru001cha | 1904 | 100 g. | New London Whalers | Connecticut State League | , | |
| Harry Armbruster | armbru001har | 1904 | 4/30-7/6 | Providence Grays | Eastern League | , | |
| Harry Armbruster | armbru001har | 1904 | 7/28-9/17 | Manchester | New England League | , | |
| Bill Armour | armour001wil | 1904 | Cleveland | American League | Cleveland, OH | ||
| Cecil Armstrong | armstr001cec | 1904 | 4/29-5/25 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Cecil Armstrong | armstr001cec | 1904 | 5/30-7/18 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Cecil Armstrong | armstr001cec | 1904 | 8/1-8/12 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Cecil Armstrong | armstr001cec | 1904 | 8 g. | Youngstown OH | Independent | , | |
| Frank Armstrong | armstr001fra | 1904 | 5/11-6/3 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |
| Lou Armstrong | armstr001lou | 1904 | 112 g. | Topeka Saints | Missouri Valley League | , | |
| Lou Armstrong | armstr001lou | 1904 | Fort Scott Giants | Missouri Valley League | , | ||
| Harry Arndt | arndt-001har | 1904 | 4/20-9/19 | Louisville Colonels | American Association | , | |
| John Arthurs | 1904 | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |||
| Ed Ashenbach | ashenb001edw | 1904 | 52 g. | Charleston Sea Gulls | South Atlantic League | , | |
| James Ashmore | ashmor001j-- | 1904 | +6/29+ | Bethany IL | Independent | , | |
| James Ashmore | ashmor001j-- | 1904 | +7/8-8/10 | Pana IL | Independent | , | |
| Jack Ashton | ashton001joh | 1904 | Vicksburg Hill Billies | Cotton States League | , | ||
| Homer Askew | askew-003--- | 1904 | 5/17-5/18+ | 4 g. | Bessemer | Tennessee-Alabama League | , |
| Homer Askew | askew-003--- | 1904 | +5/31+ | Wylam AL | Independent | , | |
| Claude Aspinwall | aspinw002--- | 1904 | 5/8-9/4 | Olympia Senators | Southwest Washington League | , | |
| Atchison | 1904 | 22 ab | Savannah Pathfinders | South Atlantic League | , | ||
| Charlie Atherton | athert001cha | 1904 | 4/29-8/9 | Montreal Royals | Eastern League | , | |
| Charlie Atherton | athert001cha | 1904 | 8/10-9/28 | Buffalo Bisons | Eastern League | , | |
| Atkins | 1904 | +9/8+ | Kansas City Blues | American Association | , | ||
| E. E. Atkins | atkins001--- | 1904 | Joplin Miners | Missouri Valley League | , | ||
| E. E. Atkins | atkins001--- | 1904 | 18 g. | Clarksdale | Delta League | , | |
| Newt Atkinson | atkins001new | 1904 | 5/16-6/4 | Huntsville | Tennessee-Alabama League | , | |
| Newt Atkinson | atkins001new | 1904 | +6/10-6/17+ | Bessemer | Tennessee-Alabama League | , | |
| Newt Atkinson | atkins001new | 1904 | 6/20-7/7 | Huntsville | Tennessee-Alabama League | , | |
| Raymond Attridge | attrid000ray | 1904 | +8/11+ | Minneapolis KS | Independent | , | |
| Jake Atz | atz---001joh | 1904 | 4/23-9/25 | New Orleans Pelicans | Southern Association | , | |
| Harry Aubrey | aubrey001har | 1904 | 4/30-9/28 | Providence Grays | Eastern League | , | |
| Jack Auslet | 1904 | +9/18+ | Alexandria LA | Independent | , | ||
| Bill Austin | austin001wil | 1904 | 39 g. | Norwich Reds | Connecticut State League | , | |
| Ike Austin | austin000ike | 1904 | , | ||||
| Jimmy Austin | austin002jam | 1904 | 4/28-9/11 | Dayton Veterans | Central League | , | |
| Jimmy Austin | austin002jam | 1904 | 11 g. | Youngstown OH | Independent | , | |
| Jimmy Austin | austin002jam | 1904 | +10/16+ | Clev.-Franklin AC | Independent | , | |
| Jack Averill | averil000jac | 1904 | 8/16-8/25 | Concord Marines | New England League | , | |
| Avery | 1904 | no g. | Minneapolis Millers | American Association | , | ||
| Avery | 1904 | 6/2- | Winnipeg Maroons | Northern League | , | ||
| Babb | babb--004--- | 1904 | +5/235/25+ | Columbia | Tennessee-Alabama League | , | |
| Charlie Babb | babb--001cha | 1904 | 151 g. | Brooklyn | National League | Brooklyn, NY | |
| George Babbitt | babbit002geo | 1904 | 130 g. | Boise Fruit Pickers | Pacific National League | , | |
| Alex Backof | backof001ale | 1904 | 4/28-7/26 | Terre Haute Hottentots | Central League | , | |
| Alex Backof | backof001ale | 1904 | 8/14-9/12 | Grand Rapids Orphans | Central League | , | |
| George Backus | backus001mel | 1904 | 7 g. | Leavenworth Orioles | Missouri Valley League | , | |
| George Backus | backus001mel | 1904 | +8/3-10/11+ | Winfield-Selects | Independent | , | |
| George Backus | backus001mel | 1904 | Winfield KS | , | |||
| Bacnac | bacnac000--- | 1904 | +4/23-4/28+ | St. Bonaventure | College | , | |
| Louis Bacon | bacon-001jam | 1904 | 5/6-9/17 | Troy Trojans | New York State League | , | |
| Frederick Badel | badel-001fre | 1904 | 79 g. | Niles OH | Independent | , | |
| Frederick Badel | badel-001fre | 1904 | Warren OH | Independent | , | ||
| Art Bader | bader-001art | 1904 | St. Louis | Trolley League | , | ||
| Art Bader | bader-001art | 1904 | 8/2-8/3 | St. Louis | American League | St. Louis, MO | |
| Art Bader | bader-001art | 1904- | Washington Univ. | College | , | ||
| Will Baer | baer--001wil | 1904 | Huntsville | Tennessee-Alabama League | , | ||
| Charles Baerwald | baerwa001cha | 1904 | 4/27-4/29 | Sioux City Soos | Western League | , | |
| Charles Baerwald | baerwa001cha | 1904 | 5/3-5/4 | Des Moines Prohibitionists | Western League | , | |
| Charles Baerwald | baerwa001cha | 1904 | 5/9-9/25 | Colorado Springs Millionaires | Western League | , | |
| Rudy Baerwald | baerwa001rud | 1904 | 99 g. | Pittsburg Coal Diggers | Missouri Valley League | , | |
| Jack Bagley | bagley001joh | 1904 | 5/10-9/27 | York Penn Parks | Tri-State League | , | |
| James Bagley | bagley004jam | 1904 | 21 g. | Fort Scott Giants | Missouri Valley League | , | |
| Emory Bagwell | bagwel001eme | 1904 | +4/12+ | Jacksonville FL | Independent | , | |
| Bailey | 1904 | 9/5-9/12 | Wheeling Stogies | Central League | , | ||
| Arch Bailey | 1904 | +6/12+ | Umpire | Texas League | , | ||
| Harvey Bailey | bailey003har | 1904 | 4/23-6/12 | Minneapolis Millers | American Association | , | |
| Harvey Bailey | bailey003har | 1904 | 6/19-7/1 | Newark Sailors | Eastern League | , | |
| Harvey Bailey | bailey003har | 1904 | 7/10-7/20 | Utica Pent-Ups | New York State League | , | |
| Harvey Bailey | bailey003har | 1904 | 8/3-8/12 | Dayton Veterans | Central League | , | |
| King Bailey | bailey001kin | 1904 | 4/21-5/? | Umpire | Southern Association | , | |
| King Bailey | bailey001kin | 1904 | +6/9- | Umpire | South Atlantic League | , | |
| King Bailey | bailey001kin | 1904 | +7/9-7/15+ | Umpire | Tennessee-Alabama League | , | |
| King Bailey | bailey001kin | 1904 | +7/27-8/17 | Decatur | Tennessee-Alabama League | , | |
| Charles Baird | 1904 | Marquette KS | Independent | , | |||
| Harry Baird | 1904 | Marquette KS | Independent | , | |||
| James Baird | baird-001jam | 1904 | no g. | Terre Haute Hottentots | Central League | , | |
| James Baird | baird-001jam | 1904 | 6/8-9/11 | Dayton Veterans | Central League | , | |
| Kid Baiseno | 1904 | 4/28-7/4 | Eugene Blues | Oregon State League | , | ||
| Baker | 1904 | 9/5-9/6 | Montgomery Senators | Southern Association | , | ||
| Ernie Baker | baker-002ear | 1904 | Baton Rouge Red Sticks | Cotton States League | , | ||
| John Baker | baker-001joh | 1904 | 32 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| L. G. Baker | baker-000lg- | 1904 | Colorado Springs Millionaires | Western League | , | ||
| Roy Baker | baker-003roy | 1904 | 5/8-9/4 | Hoquiam Perfect Gentlemen | Southwest Washington League | , | |
| Baldwin | baldwi001h-- | 1904 | 29 g. | Pittsburg Coal Diggers | Missouri Valley League | , | |
| O. H. Baldwin | baldwi001h-- | 1904 | 29 g. | Pittsburg Coal Diggers | Missouri Valley League | , | |
| O. H. Baldwin | baldwi001h-- | 1904 | Pittsburg Coal Diggers | Missouri Valley League | , | ||
| Michael Balenti | 1904-08 | Carlisle Indian | School | , | |||
| Art Ball | ball--003art | 1904 | 5/19- | Duluth White Sox | Northern League | , | |
| Eugene Ball | ball--001eug | 1904 | Fort Scott Giants | Missouri Valley League | , | ||
| Harry Ball | ball--003har | 1904 | 5/10-8/16 | York Penn Parks | Tri-State League | , | |
| Harry Ball | ball--003har | 1904 | Salisbury MD | Independent | , | ||
| Harry Ball | ball--003har | 1904 | Providence Grays | Eastern League | , | ||
| Neal Ball | ball--001cor | 1904 | 119 g. | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |
| Ballestero | balles000--- | 1904 | 5/8-9/4 | Olympia Senators | Southwest Washington League | , | |
| L. E. Ballew | ballew001l-- | 1904 | Houston Wanderers | South Texas League | , | ||
| George Balliett | ballie001geo | 1904 | 14 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| George Balliett | ballie001geo | 1904 | Rockford Red Sox | Illinois-Indiana-Iowa League | , | ||
| Joseph Bammert | bammer001joh | 1904 | 398 ab | Vicksburg Hill Billies | Cotton States League | , | |
| Oscar Bandelin | bandel002osc | 1904 | 103 g. | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Buck Bandy | 1904 | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |||
| Cecil Bankhead | bankhe001cec | 1904 | 119 g. | Iola Gasbags | Missouri Valley League | , | |
| Jack Bankhead | bankhe002jac | 1904 | 5/26 | Corsicana Oil Citys | Texas League | , | |
| Bill Bannon | bannon001wil | 1904 | 5/6-7/10 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Bill Bannon | bannon001wil | 1904 | 7/12-9/17 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| George Bannon | bannon001geo | 1904 | 115 g. | New Haven Blues | Connecticut State League | , | |
| Jimmy Bannon | bannon001jam | 1904 | 4/29-9/28 | Newark Sailors | Eastern League | , | |
| Tom Bannon | bannon001tho | 1904 | 95 g. | New London Whalers | Connecticut State League | , | |
| Tom Bannon | bannon001tho | 1904 | Hartford Senators | Connecticut State League | , | ||
| Tom Bannon | bannon001tho | 1904 | 8/4-9/1 | South Bend Greens | Central League | , | |
| Ernie Bantz | bantz-001e-- | 1904 | 5/7-9/5 | Waterloo Microbes | Iowa League | , | |
| William Barbeau | barbea001wil | 1904 | Sault Ste. Marie | Independent | , | ||
| Barber | barber019--- | 1904 | 9/18 | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Barber | barber019--- | 1904 | 9/25 | Spokane Indians | Pacific National League | , | |
| Dave Barber | barber001dav | 1904 | 5/8-9/18 | Utica Pent-Ups | New York State League | , | |
| Frank Barber | barber001fra | 1904 | Seattle Siwashes | Pacific Coast League | , | ||
| Frank Barber | barber001fra | 1904 | +7/28+ | San Francisco Seals | Pacific Coast League | , | |
| Bruce Barbour | 1904 | Oklahoma City Mets | Southwestern League | , | |||
| Louis Barbour | barbou001lou | 1904 | 53 g. | Charleston Sea Gulls | South Atlantic League | , | |
| George Barclay | barcla001geo | 1904 | 103 g. | St. Louis | National League | St. Louis, MO | |
| George Barclay | barcla001geo | 1904 | 24 g. | Boston | National League | Boston, MA | |
| John Bare | bare--001joh | 1904 | Lodi | California State League | , | ||
| John Bare | bare--001joh | 1904 | 1 g. | Tacoma Tigers | Pacific Coast League | , | |
| John Bare | bare--001joh | 1904 | Fresno | California State League | , | ||
| Cy Barger | barger001ero | 1904-05 | Transylvania Univ | College | , | ||
| Cy Barger | barger001ero | 1904 | Coatesville | Pennsylvania League | , | ||
| Billy Barker | barker002bil | 1904 | Coatesville PA | Independent | , | ||
| Billy Barker | barker002bil | 1904 | Elmira | Southern Tier League | , | ||
| Harry Barker | barker001har | 1904 | 35 g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| Robert Barlow | barlow001rob | 1904 | 5/11- | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |
| Barnes | 1904 | +5/7- | Shawnee Browns/Chickasha Indians | Southwestern League | , | ||
| Barnes | 1904 | -8/27+ | Shawnee Browns/Chickasha Indians | Southwestern League | , | ||
| Barnes | barnes012--- | 1904 | 7/8+ | Anniston | Tennessee-Alabama League | , | |
| Eugene Barnes | barnes001eug | 1904 | Oklahoma City Mets | Southwestern League | , | ||
| William Barnes | barnes001wil | 1904 | 5/16-8/17 | Sheffield | Tennessee-Alabama League | , | |
| Barnett | 1904 | +7/8+ | Shawnee Browns/Chickasha Indians | Southwestern League | , | ||
| Bill Barnett | barnet010--- | 1904 | +6/27-8/2+ | Decatur | Tennessee-Alabama League | , | |
| Jack Barnett | barnet003joh | 1904 | 5/6-9/7 | Jersey City Skeeters | Eastern League | , | |
| Barr | 1904 | 12 g. | Kent OH | Independent | , | ||
| Charley Barrett | barret002cha | 1904 | 4/30-9/2 | Fort Worth Panthers | Texas League | , | |
| Ed Barrow | barrow001edw | 1904 | Detroit | American League | Detroit, MI | ||
| Ed Barrow | barrow001edw | 1904 | 8/9-9/28 | Montreal Royals | Eastern League | , | |
| Barry | 1904 | 5/1 | Camden | Tri-State League | , | ||
| Barry | barry-030--- | 1904 | +6/28-8/20 | Boone Coal Miners | Iowa League | , | |
| Charles Barry | 1904 | Guthrie Blues | Southwestern League | , | |||
| David Barry | barry-001dav | 1904 | Paterson Intruders | Hudson River League | , | ||
| Jimmy Barry | barry-002jam | 1904 | 5/11-5/31 | New Bedford Whalers | New England League | , | |
| John Barry | barry-002joh | 1904 | Philadelphia | National League | Philadelphia, PA | ||
| John Barry | barry-002joh | 1904 | Chicago | National League | Chicago, IL | ||
| Joseph Barry | barry-003jos | 1904 | San Jose | California State League | , | ||
| Thomas Barry | barry-002tom | 1904 | Harvard Law | , | |||
| Thomas Barry | barry-002tom | 1904 | 6/24-8/9 | Buffalo Bisons | Eastern League | , | |
| Thomas Barry | barry-002tom | 1904 | 8/10-8/31 | Montreal Royals | Eastern League | , | |
| Thomas Barry | barry-002tom | 1904 | Tulane Univ. | College | , | ||
| Tom Barry | barry-001tho | 1904 | 4/15 | Philadelphia | National League | Philadelphia, PA | |
| Tom Barry | barry-001tho | 1904 | 6/4-9/18 | Kansas City Blues | American Association | , | |
| John Barthold | bartho001joh | 1904 | 5/17-6/8 | Philadelphia | American League | Philadelphia, PA | |
| John Barthold | bartho001joh | 1904 | 6/25-6/26 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| John Barthold | bartho001joh | 1904 | 7/8-8/8 | Harrisburg Senators | Tri-State League | , | |
| Bill Bartley | bartle001wil | 1904 | 4/25-9/24 | Shreveport Pirates | Southern Association | , | |
| John Bartley | bartle001joh | 1904 | 81 g. | Beaumont Millionaires | South Texas League | , | |
| Charles Bartliff | 1904 | Christian Bros. | College | , | |||
| Charles Bartliff | 1904 | Summer Olympics | , | ||||
| Harry Barton | barton001har | 1904 | 5/1 | Camden | Tri-State League | , | |
| Harry Barton | barton001har | 1904 | 5/11-9/19 | Williamsport Millionaires | Tri-State League | , | |
| James Barton | barton001jam | 1904 | 57 g. | Youngstown OH | Independent | , | |
| James Barton | barton001jam | 1904 | 8/29-9/28 | Rochester Bronchos | Eastern League | , | |
| Jack Bartos | bartos001joh | 1904 | 4/24-5/30 | St. Paul Saints | American Association | , | |
| Jack Bartos | bartos001joh | 1904 | 6/1- | 27 g. | Winnipeg Maroons | Northern League | , |
| Jack Bartos | bartos001joh | 1904 | 8/20-9/18 | Toledo Mud Hens | American Association | , | |
| Forest Bashore | bashor001for | 1904 | , | ||||
| Frank Bassett | 1904 | Umpire | Cotton States League | , | |||
| John Bassey | bassey001joh | 1904 | +8/8-9/5 | Boone Coal Miners | Iowa League | , | |
| Ward Bastian | bastia001war | 1904 | 5/28- | Cloudersport PA | Independent | , | |
| Ward Bastian | bastia001war | 1904 | 8/24-9/8 | Coudersport | Southern Tier League | , | |
| Emil Batch | batch-001emi | 1904 | Holyoke Paperweights | Connecticut State League | , | ||
| Bateman | 1904 | 52 g. | Coshocton OH | Independent | , | ||
| Fred Bateman | batema001fre | 1904 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | ||
| Quait Bateman | batema002h-- | 1904 | 4/20-9/20 | Milwaukee Brewers | American Association | , | |
| Bates | 1904 | Hudson Marines | Hudson River League | , | |||
| Bates | bates-038--- | 1904 | +7/18+ | Burlington River Rats | Iowa League | , | |
| Bates | bates-030--- | 1904 | +8/6+ | Rochester Bronchos | Eastern League | , | |
| J. A. Bates | 1904 | Corsicana Oil Citys | Texas League | , | |||
| Red Bates | bates-001red | 1904 | Ballinger TX | Independent | , | ||
| Edward Bauer | bauer-001edw | 1904 | 13 ab | Baton Rouge Red Sticks | Cotton States League | , | |
| Edward Bauer | bauer-001edw | 1904 | 47 g. | Clarksdale | Delta League | , | |
| Jacob Bauer | bauer-001jac | 1904 | 122 g. | Sedalia Goldbugs | Missouri Valley League | , | |
| Charles Baum | baum--002cha | 1904 | 55 g. | Los Angeles Angels | Pacific Coast League | , | |
| George Bausewine | bausew003geo | 1904 | 4/20-9/19 | Umpire | American Association | , | |
| Moose Baxter | baxter001joh | 1904 | 5/8-6/5 | Hoquiam Perfect Gentlemen | Southwest Washington League | , | |
| Moose Baxter | baxter001joh | 1904 | Superior Longshoremen | Northern League | , | ||
| Moose Baxter | baxter001joh | 1904 | 35 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| Moose Baxter | baxter001joh | 1904 | 9/14-9/20 | Milwaukee Brewers | American Association | , | |
| Dick Bayless | bayles001har | 1904 | 125 g. | Joplin Miners | Missouri Valley League | , | |
| Bayne | bayne-002--- | 1904 | 5/8 | Salem Raglands | Oregon State League | , | |
| Bayne | bayne-002--- | 1904 | 6/2 | Roseburg Shamrocks | Oregon State League | , | |
| Alva Bayne | bayne-001alv | 1904 | 52 g. | Macon Highlanders | South Atlantic League | , | |
| Alva Bayne | bayne-001alv | 1904 | 9/13-9/22 | Atlanta Crackers | Southern Association | , | |
| Beam | 1904 | Kingston Colonials | Hudson River League | , | |||
| J. J. Beam | 1904 | Ottumwa Standpatters | Iowa League | , | |||
| J. J. Beam | 1904 | Omaha Rangers | Western League | , | |||
| Joe Bean | bean--001jos | 1904 | 4/19-7/26 | Jersey City Skeeters | Eastern League | , | |
| Jimmy Beard | beard-001jam | 1904 | 5/4-5/24 | Chester | Pennsylvania League | , | |
| Jimmy Beard | beard-001jam | 1904 | 6/18-9/17 | Lawrence Colts | New England League | , | |
| Frank Beaumont | beaumo001fra | 1904 | Bridgeport Orators | Connecticut State League | , | ||
| Frank Beaumont | beaumo001fra | 1904 | 9/12-9/18 | Fall River Indians | New England League | , | |
| Joseph Beaver | beaver001jos | 1904 | 5/6-9/5 | Ottumwa Standpatters | Iowa League | , | |
| Erve Beck | beck--001erv | 1904 | 208 g. | Portland Browns | Pacific Coast League | , | |
| Henry Beckendorf | becken001hen | 1904 | Kingston Colonials | Hudson River League | , | ||
| Henry Beckendorf | becken001hen | 1904 | 9/28 | Montreal Royals | Eastern League | , | |
| Beals Becker | becker001dav | 1904 | +7/19-9/5 | Oklahoma City Mets | Southwestern League | , | |
| Beals Becker | becker001dav | 1904 | Guthrie Blues | Southwestern League | , | ||
| Bob Becker | becker001bob | 1904 | 5/4-7/3 | Rochester Bronchos | Eastern League | , | |
| Hubert Becker | 1904 | no g. | Utica Pent-Ups | New York State League | , | ||
| P. B. Becker | 1904 | Springfield Midgets | Missouri Valley League | , | |||
| Jake Beckley | beckle001jac | 1904 | 142 g. | St. Louis | National League | St. Louis, MO | |
| Frank Bedur | bedur-001ott | 1904 | 53 g. | Canton OH | Independent | , | |
| Frank Bedur | bedur-001ott | 1904 | Warren OH | Independent | , | ||
| Frank Bedur | bedur-001ott | 1904 | Marietta OH | Independent | , | ||
| Frank Bedur | bedur-001ott | 1904 | +7/31+ | Canton | Delta League | , | |
| Beecher | 1904 | Binghamton Bingoes | New York State League | , | |||
| John Beedles | beedle002joh | 1904 | Decatur Commodores | Illinois-Indiana-Iowa League | , | ||
| John Beedles | beedle002joh | 1904 | 5/1 | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| John Beedles | beedle002joh | 1904 | +5/16+ | Umpire | Illinois-Indiana-Iowa League | , | |
| William Beeker | beeker001wil | 1904 | 31 g. | Clarksdale | Delta League | , | |
| James Begley | 1904 | 21 g. | Fort Scott Giants | Missouri Valley League | , | ||
| Billy Belden | belden001wil | 1904 | 4/28-9/11 | Fort Wayne Railroaders | Central League | , | |
| Ira Belden | belden002ira | 1904 | 4/24-9/25 | St. Joseph Saints | Western League | , | |
| George Bell | bell--002geo | 1904 | 5/11-9/11 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Theron Bell | bell--001t-- | 1904 | 46 g. | Canton | Delta League | , | |
| Frank Belt | belt--001fra | 1904 | preseason | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Frank Belt | belt--001fra | 1904 | 4/24-5/9 | Memphis Egyptians | Southern Association | , | |
| Frank Belt | belt--001fra | 1904 | 243 ab | Vicksburg Hill Billies | Cotton States League | , | |
| Harry Belt | belt--001hic | 1904 | 5/8-9/4 | Aberdeen Pippins | Southwest Washington League | , | |
| Oren Beltzer | beltze001buc | 1904-10 | Univ. Nebraska | College | , | ||
| Oren Beltzer | beltze001buc | 1904-10 | Oxford Indians | Independent | , | ||
| Charles Bemiss | bemis-001cha | 1904 | 5/19- | 24 g. | Winnipeg Maroons | Northern League | , |
| Charles Bender | bender001cha | 1904 | Philadelphia | American League | Philadelphia, PA | ||
| John Bender | bender002joh | 1904 | 21 g. | Hartford Senators | Connecticut State League | , | |
| John Bender | bender002joh | 1904 | 29 g. | Fargo | Northern League | , | |
| Eugene Bene | bene--001eug | 1904 | 5 g. | Fort Scott Giants | Missouri Valley League | , | |
| Bennett | bennet001si- | 1904 | 16 g. | Superior Longshoremen | Northern League | , | |
| Bennett | 1904 | 6/3-9/6 | Altoona Mountaineers | Tri-State League | , | ||
| Bennett | 1904 | 7/21 | Paris Parasites/Ardmore Territorians | Texas League | , | ||
| Bennett | 1904 | 7/26+ | Dallas-Elks | Amateur | , | ||
| A. J. Bennett | bennet001a-- | 1904 | Oklahoma City Mets | Southwestern League | , | ||
| Ben Bennett | bennet002ben | 1904 | +7/13-9/27+ | Guthrie Blues | Southwestern League | , | |
| Davy Bennett | 1904 | 6/3-9/6 | Altoona Mountaineers | Tri-State League | , | ||
| Pug Bennett | bennet001jus | 1904 | 4/21-9/24 | Nashville Volunteers | Southern Association | , | |
| Simon Bennett | bennet001si- | 1904 | 16 g. | Superior Longshoremen | Northern League | , | |
| Benson | benson005--- | 1904 | 19 g. | Superior Longshoremen | Northern League | , | |
| Benson | benson005--- | 1904 | 8/14-8/26+ | Lake Linden Lakers | Copper Country League | , | |
| Benson | benson005--- | 1904 | +6/13- | 12 g. | Winnipeg Maroons | Northern League | , |
| Ben Benson | 1904 | Grinnell College | College | , | |||
| Ben Benson | 1904 | Davenport River Rats | Illinois-Indiana-Iowa League | , | |||
| Bentel | 1904 | 14 g. | Alliance OH | Independent | , | ||
| Roy Bentlet | 1904 | Enid Evangelists | Southwestern League | , | |||
| William Bentley | bentle001wil | 1904 | Columbia SC | Independent | , | ||
| James Berber | 1904 | Hudson Marines | Hudson River League | , | |||
| Peter Berg | berg--001pet | 1904 | 22 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Dan Bergen | 1904 | 7/24- | Camden NJ | Independent | , | ||
| Heinie Berger | berger001cha | 1904 | 4/21-5/3 | Columbus Senators | American Association | , | |
| Heinie Berger | berger001cha | 1904 | 6/1-6/7 | Minneapolis Millers | American Association | , | |
| Heinie Berger | berger001cha | 1904 | Mt. Vernon | Independent | , | ||
| Heinie Berger | berger001cha | 1904 | 8/28-9/20 | Columbus Senators | American Association | , | |
| James Berger | berger001jam | 1904 | 129 g. | Hudson Marines | Hudson River League | , | |
| Joseph Berger | 1904 | StL-Indep | Independent | , | |||
| Curt Bernard | bernar001cur | 1904 | 195 g, | Los Angeles Angels | Pacific Coast League | , | |
| Sam Bernard | bernar001sam | 1904 | 5/17-5/26 | Lawrence Colts | New England League | , | |
| Bill Bernhard | bernha001wil | 1904 | 38 g. | Cleveland | American League | Cleveland, OH | |
| Berry | berry-016--- | 1904 | 7/10 | Centralia Midgets | Southwest Washington League | , | |
| Charles Berry | 1904-05 | , | |||||
| Claude Berry | berry-001cla | 1904 | 4/22- | 3 g. | Chicago | American League | Chicago, IL |
| Claude Berry | berry-001cla | 1904 | 5/20-9/20 | Indianapolis Indians | American Association | , | |
| Harry Berry | berry-002har | 1904 | 218 ab | Pine Bluff Lumbermen | Cotton States League | , | |
| Hodge Berry | berry-000hod | 1904 | a college in OH | , | |||
| Hodge Berry | berry-000hod | 1904 | 5/19 | Sioux City Soos | Western League | , | |
| Joe Berry | berry-001jos | 1904 | 5/6-5/14 | Utica Pent-Ups | New York State League | , | |
| Joe Berry | berry-001jos | 1904 | 6/30-7/13+ | Hornellsville Maple Cities | Southern Tier League | , | |
| Bob Berryhill | berryh001rob | 1904 | 4/28-8/1 | Evansville River Rats | Central League | , | |
| Bob Berryhill | berryh001rob | 1904 | Umpire | Central League | , | ||
| Harry Berte | berte-001har | 1904 | 122 g. | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |
| Sidney Berte | berte-000sid | 1904 | no g. | Denver Grizzlies | Western League | , | |
| Sidney Berte | berte-000sid | 1904 | no g. | Columbus Senators | American Association | , | |
| Sidney Berte | berte-000sid | 1904 | 5/20-6/7 | Dayton Veterans | Central League | , | |
| Sidney Berte | berte-000sid | 1904 | 6/9 | Evansville River Rats | Central League | , | |
| James Bertwhistle | bertwh001jam | 1904 | 73 g. | Hartford Senators | Connecticut State League | , | |
| Conrad Best | best--001con | 1904 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | ||
| Conrad Best | best--001con | 1904 | 22 g. | Hattiesburg | Delta League | , | |
| Ed Betch | betch-001ed- | 1904 | +5/21+ | Shawnee Browns/Chickasha Indians | Southwestern League | , | |
| Fred Betts | betts-001fre | 1904 | 5/6-7/10 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Fred Betts | betts-001fre | 1904 | 7/12-9/17 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Harry Betts | betts-002har | 1904 | 5/9-5/13 | Binghamton Bingoes | New York State League | , | |
| Harry Betts | betts-002har | 1904 | Newburgh Taylor-mades | Hudson River League | , | ||
| Carlton Beusse | beusse001car | 1904 | 5/16-5/24 | Anniston | Tennessee-Alabama League | , | |
| Carlton Beusse | beusse001car | 1904 | +6/9-8/23+ | Columbia Skyscrapers | South Atlantic League | , | |
| Beville | bevill001--- | 1904 | 18 g. | Brookhaven | Delta League | , | |
| Burley Beville | 1904 | 5/11- | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | ||
| Monte Beville | bevill001hen | 1904 | New York | American League | New York, NY | ||
| Monte Beville | bevill001hen | 1904 | Detroit | American League | Detroit, MI | ||
| Monte Beville | bevill001hen | 1904 | 5/24-7/7 | Providence Grays | Eastern League | , | |
| Roy Bevis | bevis-001roy | 1904 | 99 g. | Sedalia Goldbugs | Missouri Valley League | , | |
| Roy Bevis | bevis-001roy | 1904 | Topeka Saints | Missouri Valley League | , | ||
| Joseph Bewer | bewer-001jos | 1904 | Ottumwa Standpatters | Iowa League | , | ||
| Ed Biecher | bieche001ed- | 1904 | 4/23-9/24 | Memphis Egyptians | Southern Association | , | |
| Joseph Biehl | biehl-001jos | 1904 | Pottstown PA | Independent | , | ||
| Joseph Biehl | biehl-003--- | 1904 | 8/1- | Elmira | Southern Tier League | , | |
| John Bierkotte | 1904 | rel. 6/4 | 2 g. | Huntsville | Tennessee-Alabama League | , | |
| John Bierkotte | 1904 | +8/17+ | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | ||
| Fred Bierman | bierma001fre | 1904 | 5/16- | Concord Marines | New England League | , | |
| Fred Bierman | bierma001fre | 1904 | -6/27 | Lawrence Colts | New England League | , | |
| Albert Biery | biery-001rob | 1904 | Canton OH | Semi-professional | , | ||
| Albert Biery | biery-001rob | 1904 | no g. | Indianapolis Indians | American Association | , | |
| Albert Biery | biery-001rob | 1904 | 13 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Albert Biery | biery-001rob | 1904 | 6/2-9/11 | Dayton Veterans | Central League | , | |
| George Bigbie | bigbie001geo | 1904 | 4/30-9/17 | Lowell Tigers | New England League | , | |
| Harry Billett | billet001har | 1904 | 5/10-9/30 | York Penn Parks | Tri-State League | , | |
| Ben Bills | 1904 | Schenectady Electricians/Scranton Miners | New York State League | , | |||
| E. Bills | 1904 | Poughkeepsie Colts | Hudson River League | , | |||
| Joseph Bills | bills-001jos | 1904 | 9/19 | Sioux City Soos | Western League | , | |
| Charles Bilyeu | bilyeu000cha | 1904 | 4/30-7/4 | Roseburg Shamrocks | Oregon State League | , | |
| Daniel Binnard | 1904 | , | |||||
| Harry Bird | bird--001har | 1904 | Oakland | California State League | , | ||
| Thomas Bird | bird--001tho | 1904 | Univ. of Michigan | College | , | ||
| Thomas Bird | bird--001tho | 1904 | 8/23 | Rochester Bronchos | Eastern League | , | |
| Joe Birmingham | birmin001jos | 1904-05 | Cornell University | College | , | ||
| Joe Birmingham | birmin001jos | 1904 | 6/29-9/10 | Elmira | Southern Tier League | , | |
| Mike Birmingham | birmin001mic | 1904 | 4/30- | Lawrence Colts | New England League | , | |
| Mike Birmingham | birmin001mic | 1904 | Manchester | New England League | , | ||
| Mike Birmingham | birmin001mic | 1904 | -9/17 | Nashua | New England League | , | |
| Charles Bishop | bishop002cha | 1904 | 18 g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| John Bishop | bishop001joh | 1904 | 5/3 | Montreal Royals | Eastern League | , | |
| Wilbert Bissell | bissel001wil | 1904 | Fort Wayne Railroaders | Central League | , | ||
| Wilbert Bissell | bissel001wil | 1904 | 61 g. | Coshocton OH | Independent | , | |
| Wilbert Bissell | bissel001wil | 1904 | 8/23- | Kent OH | Independent | , | |
| John Bissett | bisset001joh | 1904 | 451 ab | Paterson Intruders | Hudson River League | , | |
| George Bittrolff | bittro001geo | 1904 | 21+ g. | Cairo Champions | Kentucky-Illinois-Tennessee League | , | |
| Black | 1904 | 7/26-7/28 | Fort Worth Panthers | Texas League | , | ||
| Black | black-027--- | 1904 | 4/24-4/27 | Sioux City Soos | Western League | , | |
| Cyrus Black | black-001cyr | 1904 | 5/7-9/5 | Keokuk Indians | Iowa League | , | |
| Harry Black | black-001har | 1904 | Gloucester NJ | Independent | , | ||
| Harry Black | black-001har | 1904 | Cambridge MD | Independent | , | ||
| Harvey Black | 1904 | Umpire | South Atlantic League | , | |||
| Robert Black | black-003bob | 1904 | 5/23-7/6 | Waterloo Microbes | Iowa League | , | |
| Robert Black | black-003bob | 1904 | 7/8-9/5 | Burlington River Rats | Iowa League | , | |
| Robert Black | black-003rob | 1904 | Umpire | South Atlantic League | , | ||
| Robert Black | black-003rob | 1904 | Jacksonville Jays | South Atlantic League | , | ||
| Robert Black | black-003rob | 1904 | 9/5-9/10 | Umpire | South Atlantic League | , | |
| Charles Blackburn | blackb001cha | 1904 | +5/9+ | 55 g. | Galveston Sand Crabs | South Texas League | , |
| Charles Blackburn | blackb001cha | 1904 | +6/11-8/31+ | San Antonio Bronchos | South Texas League | , | |
| George Blackburn | blackb001geo | 1904 | Natchez Indians | Cotton States League | , | ||
| George Blackburn | blackb001geo | 1904 | Greenville Cotton Pickers | Cotton States League | , | ||
| Joe Blackburn | blackb002r-- | 1904 | 5/20-7/14+ | Clarksdale | Delta League | , | |
| Blair | blair-017--- | 1904 | 7/8-8/19 | Wellsville Oil Drillers | Southern Tier League | , | |
| Guy Blair | blair-001guy | 1904 | Rockford Red Sox | Illinois-Indiana-Iowa League | , | ||
| Guy Blair | blair-001guy | 1904 | +5/10+ | Ottumwa Standpatters | Iowa League | , | |
| Walter Blair | blair-001wal | 1904 | Coudersport PA | Independent | , | ||
| Walter Blair | blair-001wal | 1904 | Ardmore IT | Independent | , | ||
| Walter Blair | blair-001wal | 1904 | 8/5-8/14 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Bill Blake | blake-001wil | 1904 | Louisville Colonels | American Association | , | ||
| Bill Blake | blake-001wil | 1904 | 105 g. | Macon Highlanders | South Atlantic League | , | |
| Bill Blake | blake-001wil | 1904 | 9/17-9/24 | Little Rock Travelers | Southern Association | , | |
| Frank Blake | blake-001wil | 1904 | 105 g. | Macon Highlanders | South Atlantic League | , | |
| Frank Blake | blake-001wil | 1904 | 9/17-9/24 | Little Rock Travelers | Southern Association | , | |
| Harry Blake | blake-001har | 1904 | 4/24-9/25/ | Colorado Springs Millionaires | Western League | , | |
| Bill Blakey | blakey001wil | 1904 | 4/30-6/5 | Grand Rapids Orphans | Central League | , | |
| Bill Blakey | blakey001wil | 1904 | 23 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Foster Blanchard | blanch001fos | 1904 | Kingston Colonials | Hudson River League | , | ||
| Ben Blanchette | blanch001ben | 1904 | 5/17-5/23 | Beaumont Millionaires | South Texas League | , | |
| Cliff Blankenship | blanke001cli | 1904 | Seattle Siwashes | Pacific Coast League | , | ||
| Arch Blasingim | blasin001a-- | 1904 | 5/14-8/15 | Corsicana Oil Citys | Texas League | , | |
| John Blass | blass-001joh | 1904 | +3/20-7/3 | N.O.-Gold Bands | New Orleans Commercial League | , | |
| John Blass | blass-001joh | 1904 | 129 ab | Monroe Hill Citys | Cotton States League | , | |
| John Blass | blass-001joh | 1904 | 6/19 | New Orleans Pelicans | Southern Association | , | |
| Alfred Blatchford | blatch001alf | 1904 | 25 g. | New Bedford Whalers | New England League | , | |
| Bledsoe | bledso001--- | 1904 | +5/24+ | 7 g. | Columbia | Tennessee-Alabama League | , |
| Bob Blewett | blewet001rob | 1904 | 4/30-6/1 | Boise Fruit Pickers | Pacific National League | , | |
| Bob Blewett | blewet001rob | 1904 | 9/25 | Spokane Indians | Pacific National League | , | |
| Theodore Blexrud | blexru001mel | 1904 | +7/13+ | Bismarck ND | Independent | , | |
| Elmer Bliss | bliss-001elm | 1904 | 5/11 | New York | American League | New York, NY | |
| Elmer Bliss | bliss-001elm | 1904 | 5/21-5/27 | Baltimore Orioles | Eastern League | , | |
| Elmer Bliss | bliss-001elm | 1904 | 6/4-8/1 | Montreal Royals | Eastern League | , | |
| Elmer Bliss | bliss-001elm | 1904 | 8/9-9/28 | Rochester Bronchos | Eastern League | , | |
| Albert Blough | blough000as- | 1904 | Evansville River Rats | Central League | , | ||
| J. A. Blough | 1904 | Harrisburg PA | Independent | , | |||
| Curley Blount | blount001iow | 1904 | no g. | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Curley Blount | blount001iow | 1904 | 75 g. | Youngstown OH | Independent | , | |
| Bert Blue | blue--001bir | 1904 | 150 ab | Pine Bluff Lumbermen | Cotton States League | , | |
| Bert Blue | blue--001bir | 1904 | 14 g. | Findlay OH | Independent | , | |
| John Blue | blue--003joh | 1904 | 8 ab | Natchez Indians | Cotton States League | , | |
| Fred Bluth | bluth-001god | 1904 | 33 g. | Salt Lake City Elders | Pacific National League | , | |
| Boals | boals-000--- | 1904 | 5/5-5/8 | Des Moines Prohibitionists | Western League | , | |
| George Boardman | boardm001geo | 1904 | 4/30- | Lawrence Colts | New England League | , | |
| George Boardman | boardm001geo | 1904 | -9/17 | Haverhill Hustlers | New England League | , | |
| John Bockstahler | bockst001j-- | 1904 | 6/29-8/12 | Penn Yan Grape Pickers | Southern Tier League | , | |
| Oscar Boettiger | boetti001osc | 1904 | San Francisco | California State League | , | ||
| Oscar Boettiger | boetti001osc | 1904 | 6/26-9/4 | Hoquiam Perfect Gentlemen | Southwest Washington League | , | |
| Richard Boettiger | boetti001ric | 1904 | San Francisco | California State League | , | ||
| Richard Boettiger | boetti001ric | 1904 | +4/23+ | 25 g. | Oakland Oaks | Pacific Coast League | , |
| Richard Boettiger | boetti001ric | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| Luke Bohannon | bohann001l-- | 1904 | Greenville Cotton Pickers | Cotton States League | , | ||
| Luke Bohannon | bohann001l-- | 1904 | 53 g. | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | |
| Patrick Bohannon | bohann001pat | 1904 | 4/24-9/18 | Louisville Colonels | American Association | , | |
| Walter Boles | boles-001wal | 1904 | 4/27-8/15 | Fort Worth Panthers | Texas League | , | |
| John Bolin | bolin-003joh | 1904 | 4/24-9/24 | Little Rock Travelers | Southern Association | , | |
| Charles Bomar | bomar-001cha | 1904 | 32+ g. | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |
| Charles? Bomar | bomar-001--- | 1904 | 6/8-6/26 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Carl Bond | bond--001car | 1904 | Nebraska Indians | Independent | , | ||
| Harold Bond | bond--001har | 1904 | +6/29+ | Bowesmont ND | Independent | , | |
| George Bone | bone--001geo | 1904 | 98 g. | Meriden Silverites | Connecticut State League | , | |
| Doug Bonham | bonham000--- | 1904 | Corning White Ponies | Southern Tier League | , | ||
| Frank Bonner | bonner001fra | 1904 | 4/20-9/20 | Kansas City Blues | American Association | , | |
| Jack Bonner | bonner001joh | 1904 | 5/1-9/30 | Harrisburg Senators | Tri-State League | , | |
| Joseph Bonner | 1904 | Drifton PA | Independent | , | |||
| Frank Bonnett | bonnet001fra | 1904 | no g. | Dayton Veterans | Central League | , | |
| Frank Bonnett | bonnet001fra | 1904 | Youngstown OH | Independent | , | ||
| Gus Bonno | bonno-001gus | 1904 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | ||
| Gus Bonno | bonno-001gus | 1904 | Charleston WV | Independent | , | ||
| Harry Bonthrom | 1904 | 4/22- | ChambersburgPA | Independent | , | ||
| Harry Bonthrom | 1904 | Coatesville | Pennsylvania League | , | |||
| George Booth | booth-001geo | 1904 | 167 ab | Hudson Marines | Hudson River League | , | |
| Vic Borden | borden001vic | 1904 | Addison NY | Independent | , | ||
| Charles Borman | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |||
| Charles Botsford | bottsf001cha | 1904 | 6/2- | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Charles Botsford | bottsf001cha | 1904 | 7/27-8/2 | Burlington River Rats | Iowa League | , | |
| Billy Bottenus | botten001wil | 1904 | 5/14-6/13 | Grand Rapids Orphans | Central League | , | |
| Billy Bottenus | botten001wil | 1904 | 24 g. | Plattsburgh | Northern New York League | , | |
| Jim Bouldin | bouldi001jam | 1904 | +6/10+ | 9 g.? | Leavenworth Orioles | Missouri Valley League | , |
| Jim Bouldin | bouldi001jam | 1904 | +9/25-10/9+ | Geary OT | Independent | , | |
| Bourdon | bourdo000--- | 1904 | 5/11 | Fall River Indians | New England League | , | |
| Victor Bourdon | bosler001edw | 1904 | 4/30- | Haverhill Hustlers | New England League | , | |
| Victor Bourdon | bosler001edw | 1904 | -5/27 | Nashua | New England League | , | |
| Victor Bourdon | bosler001edw | 1904 | 7/27- | Towanda PA | Independent | , | |
| Benny Bowcock | bowcoc001ben | 1904 | 4/20-5/14 | Columbus Senators | American Association | , | |
| Benny Bowcock | bowcoc001ben | 1904 | 6/17-9/19 | Fall River Indians | New England League | , | |
| Bowden | bowden001--- | 1904 | Lodi | California State League | , | ||
| Cy Bowen | bowen-001sut | 1904 | 5/8-9/18 | Ilion Typewriters | New York State League | , | |
| John Bowen | 1904 | Furman | College | , | |||
| Frank Bowerman | bowerm001fra | 1904 | 93 g. | New York | National League | New York, NY | |
| Rube Bowers | bowers001d-- | 1904 | 5/8-8/13 | Albany Senators | New York State League | , | |
| Rube Bowers | bowers001d-- | 1904 | 9/27 | York Penn Parks | Tri-State League | , | |
| Goldie Bowler | bowler001p-- | 1904 | 35 g. | Springfield Ponies | Connecticut State League | , | |
| Frank Bowman | bowman001fra | 1904 | Los Angeles Angels | Pacific Coast League | , | ||
| Martin Bowman | 1904 | no g. | Burlington River Rats | Iowa League | , | ||
| Morgan Bowman | 1904 | Yale University | College | , | |||
| William Bowman | bowman006wil | 1904 | Spokane Indians | Pacific National League | , | ||
| William Bowman | bowman006wil | 1904 | Boise City | , | |||
| August Boxbaum | 1904 | 9/5-9/11 | South Bend Greens | Central League | , | ||
| Boyd | 1904 | Yazoo City Zoos | Delta League | , | |||
| Earl Boyd | boyd--001ear | 1904 | 4/27-7/3 | Dallas Giants | Texas League | , | |
| Earl Boyd | boyd--001ear | 1904 | 7/4-8/15 | Corsicana Oil Citys | Texas League | , | |
| Smith? Boyd | boyd--012--- | 1904 | Natchez Indians | Cotton States League | , | ||
| Tommy Boyd | 1904 | 7/24- | Camden NJ | Independent | , | ||
| C. H.? Boylan | boylan006--- | 1904 | 8/16 | Louisville Colonels | American Association | , | |
| James Boylan | boylan001jam | 1904 | +6/28-8/3+ | Sheffield | Tennessee-Alabama League | , | |
| John Boylan | boylan000joh | 1904 | 21 g. | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |
| Frank Boyle | boyle-001fra | 1904 | 5/18-6/10 | Fort Dodge Gypsum Eaters | Iowa League | , | |
| Frederick Boyle | boyle-001f-- | 1904 | -8/2 | Akron OH | Independent | , | |
| Frederick Boyle | boyle-001f-- | 1904 | 21 g. | Sharon PA | Independent | , | |
| Grover Boyle | boyle-001gro | 1904 | 3 g. | Seattle Siwashes | Pacific Coast League | , | |
| Walter Boyson | boyson000wal | 1904 | +4/30+ | Cambridge MA | Independent | , | |
| Jack Bracken | bracke001joh | 1904 | 4/25-5/19 | Little Rock Travelers | Southern Association | , | |
| Jack Bracken | bracke001joh | 1904 | Baton Rouge Red Sticks | Cotton States League | , | ||
| Jack Bracken | bracke001joh | 1904 | 8/13-8/30 | Little Rock Travelers | Southern Association | , | |
| John Brackenridge | bracke002joh | 1904 | 4/15-5/30 | Philadelphia | National League | Philadelphia, PA | |
| John Brackenridge | bracke002joh | 1904 | 6/21-9/27 | Newark Sailors | Eastern League | , | |
| Bradley | 1904 | 9/10 | Providence Grays | Eastern League | , | ||
| Ernest Bradley | bradle001ern | 1904 | 4.29-6/26+ | Roseburg Shamrocks | Oregon State League | , | |
| Ernest Bradley | bradle001ern | 1904 | +7/19+ | Portland Browns | Pacific Coast League | , | |
| G.W. Bradley | bradle001g-- | 1904 | Bensonhurst | Independent | , | ||
| James Bradley | bradle001jam | 1904 | Plainfield NJ | Independent | , | ||
| James Bradley | bradle001jam | 1904 | 9/17 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Clyde Bradshaw | bradsh001cly | 1904 | 5/6-9/5 | Oskaloosa Quakers | Iowa League | , | |
| Frank Brady | brady-001fra | 1904 | 6+ g. | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |
| George Brady | brady-001geo | 1904 | 18+ g. | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| Thomas Brady | 1904 | 7/18-9/17 | Umpire | New England League | , | ||
| Brage | 1904 | 5/13 exh. | Wilmington Peaches | Tri-State League | , | ||
| Edward Brahic | brahic000edd | 1904 | Nebraska Indians | Independent | , | ||
| Edward Brahic | brahic000edd | 1904 | 8/31- | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | |
| Louis Brahic | brahic000dic | 1904 | 5/11- | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| Edward Brahm | brahm-000edw | 1904 | +8/2-10/14 | Massillon OH | Independent | , | |
| Brand | brand-000--- | 1904 | 7/20- | Hornellsville Maple Cities | Southern Tier League | , | |
| Chick Brandom | brando001che | 1904 | Oklahoma City Mets | Southwestern League | , | ||
| Chick Brandom | brando001che | 1904 | +9/3+ | Pittsburg Coal Diggers | Missouri Valley League | , | |
| Edward Brandon | brando001e-- | 1904 | +9/12+ | Pittsburg Coal Diggers | Missouri Valley League | , | |
| Willis Brandon | brando001e-- | 1904 | 9 g. | Pittsburg Coal Diggers | Missouri Valley League | , | |
| Alvin Brandt | 1904 | 4/30-5/2 | Galveston Sand Crabs | South Texas League | , | ||
| Rumple Brandt | 1904 | Umpire | South Atlantic League | , | |||
| Willie Brandt | brandt002wil | 1904 | 8/6-9/20 | Montgomery Senators | Southern Association | , | |
| Brannon | branno003--- | 1904 | 5/18 | Columbia | Tennessee-Alabama League | , | |
| Bransfield | 1904 | 5 g. | Akron OH | Independent | , | ||
| Kitty Brashear | brashe001nor | 1904 | 150 g. | Seattle Siwashes | Pacific Coast League | , | |
| Kitty Brashear | brashe001nor | 1904 | Los Angeles Angels | Pacific Coast League | , | ||
| Roy Brashear | brashe002roy | 1904 | 4/20-9/19 | Louisville Colonels | American Association | , | |
| Harry Bratton | bratto001har | 1904 | 17 g. | Savannah Pathfinders | South Atlantic League | , | |
| Robert Braun | braun-001rob | 1904 | 2 ab | Vicksburg Hill Billies | Cotton States League | , | |
| Silver Braun | braun-005wil | 1904 | 4/24-9/19 | Denver Grizzlies | Western League | , | |
| William Braun | braun-004wil | 1904 | 15 g. | Hattiesburg | Delta League | , | |
| Bray | 1904 | 8/2-8/7 | Grand Forks Forkers | Northern League | , | ||
| Billy Bray | bray--002wil | 1904 | Grand Forks Forkers | Northern League | , | ||
| Billy Bray | bray--002wil | 1904 | 7/25-8/9 | Grand Forks Forkers | Northern League | , | |
| Otis Brazell | brazze001oti | 1904 | Brookhaven | Delta League | , | ||
| Breckbill | 1904 | Latrobe PA | Independent | , | |||
| Bredemeier | bredem000--- | 1904 | 6/4 | Roseburg Shamrocks | Oregon State League | , | |
| Oscar Breeding | 1904 | 8/22-8/27 | Houston Wanderers | South Texas League | , | ||
| Jimmie Breen | breen-002jam | 1904 | 18 g. | Warren OH | ProtAssn | , | |
| A. J. Breitang | 1904 | Natchez Indians | Cotton States League | , | |||
| Bill Breitenstein | breite001wil | 1904 | Natchez Indians | Cotton States League | , | ||
| Theodore Breitenstein | breite001the | 1904 | 4/23-9/20 | New Orleans Pelicans | Southern Association | , | |
| Brekke | 1904 | +4/22+ | , | ||||
| Frank Brenig | brenig000fra | 1904 | Raleigh BB Asso. | , | |||
| John Brennan | brenna009joh | 1904 | Hartford Senators | Connecticut State League | , | ||
| John Brennan | brenna009joh | 1904 | Plattsburg | Independent | , | ||
| John Brennan | brenna002joh | 1904 | 4/29-5/2 | Dayton Veterans | Central League | , | |
| John Brennan | brenna002joh | 1904 | 5/4 | Grand Rapids Orphans | Central League | , | |
| John Brennan | brenna002joh | 1904 | Piqua OH | Independent | , | ||
| John Brennan | brenna002joh | 1904 | June | Urbana | Independent | , | |
| John Brennan | 1904 | Toro-Wellingtons | Independent | , | |||
| Brennen | 1904 | +6/11+ | Lawrence Colts | New England League | , | ||
| Brennon | 1904 | 5/29 | Schenectady Electricians/Scranton Miners | New York State League | , | ||
| Brent | brent-007--- | 1904 | 4/28-10/3 | Coatesville PA | Chester County | , | |
| James Brent | 1904 | Savannah Pathfinders | South Atlantic League | , | |||
| Rube Bressler | bressl001har | 1904 | 5/20-8/23 | Williamsport Millionaires | Tri-State League | , | |
| Mike Breyette | breyet001mic | 1904 | 5/19- | 48 g. | Crookston Crooks | Northern League | , |
| Mike Breyette | breyet001mic | 1904 | 8/11-8/22 | Sioux City Soos | Western League | , | |
| Harry Breymaier | 1904 | +6/7+ | Zoar OH | Independent | , | ||
| Charles Brice | brice-000cha | 1904 | Saugerties | Hudson River League | , | ||
| Fred Bridges | bridge001fre | 1904 | 5/6-8/23+ | Oskaloosa Quakers | Iowa League | , | |
| Marvin Bridges | bridge002mar | 1904 | +6/21-6/25 | Columbia | Tennessee-Alabama League | , | |
| Marvin Bridges | bridge002mar | 1904 | 6/29-7/4 | Atlanta Crackers | Southern Association | , | |
| Marvin Bridges | bridge002mar | 1904 | +7/12-8/20 | Chattanooga | Tennessee-Alabama League | , | |
| Al Bridwell | bridwe001alb | 1904 | 4/20-9/20 | Columbus Senators | American Association | , | |
| Buttons Briggs | briggs001her | 1904 | 34 g. | Chicago | National League | Chicago, IL | |
| Ollie Bright | bright008--- | 1904 | +4/7-7/6+ | Emporia State U. | College | , | |
| Charles Brinker | brinke000cha | 1904 | 6/13 | Rochester Bronchos | Eastern League | , | |
| Charles Brinker | brinke000cha | 1904 | +9/6+ | Batavia NY | Independent | , | |
| Charles Brinker | brinke000cha | 1904 | Roch.-Naveys | Rochester Indoor League | , | ||
| William Brinker | brinke001wil | 1904 | Sedro-Wooley WA | Independent | , | ||
| Frank Brisbine | brisbi001fra | 1904 | Homestead PA | Independent | , | ||
| Albert Briseno | brisen001alb | 1904 | 4/28-7/4 | Eugene Blues | Oregon State League | , | |
| Albert Briseno | brisen001alb | 1904 | Stockton | California State League | , | ||
| Joseph Briskey | briske001jos | 1904 | 87 g. | Houston Wanderers | South Texas League | , | |
| Joseph Briskey | briske001jos | 1904 | +7/10+ | Galveston Sand Crabs | South Texas League | , | |
| Joseph Briskey | briske001jos | 1904 | +8/17-8/21+ | San Antonio Bronchos | South Texas League | , | |
| Joseph Briskey | briske001jos | 1904 | Umpire | South Texas League | , | ||
| Bristow | 1904 | Newburgh Taylor-mades | Hudson River League | , | |||
| George Bristow | bristo002geo | 1904 | 4 g. | Seattle Siwashes | Pacific Coast League | , | |
| George Bristow | bristo002geo | 1904 | 6/5-9/25 | Spokane Indians | Pacific National League | , | |
| Sherman Bristow | bristo001she | 1904 | 5/6-5/7 | Binghamton Bingoes | New York State League | , | |
| Sherman Bristow | bristo001she | 1904 | no g. | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| Sherman Bristow | bristo001she | 1904 | 7/23-7/24 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Sherman Bristow | bristo001she | 1904 | 7/25 | Wheeling Stogies | Central League | , | |
| Sherman Bristow | bristo001she | 1904 | 7/26-8/13 | Grand Rapids Orphans | Central League | , | |
| Sherman Bristow | bristo001she | 1904 | 8/17-9/6 | Evansville River Rats | Central League | , | |
| Sherman Bristow | bristo001she | 1904 | 9/7-9/11 | Terre Haute Hottentots | Central League | , | |
| William Brittsan | britts001w-- | 1904 | 30 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Broadbent | 1904 | +6/11+ | NCast-Athletics | Independent | , | ||
| William Broadhurst | broadh001wil | 1904 | 5/7-5/23 | Bellingham WA | Independent | , | |
| William Broadhurst | broadh001wil | 1904 | 5/29-9/4 | Aberdeen Pippins | Southwest Washington League | , | |
| King Brockett | brocke001lew | 1904 | 4/30-9/27 | Buffalo Bisons | Eastern League | , | |
| Billy Brockhoff | brockh001wil | 1904 | +5/29+ | Bellingham WA | Independent | , | |
| Billy Brockhoff | brockh001wil | 1904 | Sedro-Woolley | Amateur | , | ||
| Antone Brodahl | brodah001--- | 1904 | 5/8-6/5 | Centralia Midgets | Southwest Washington League | , | |
| Matt Broderick | broder001mat | 1904 | 5/1-9/30 | Harrisburg Senators | Tri-State League | , | |
| William Broderick | broder001wil | 1904 | 7/6-7/9 | New Bedford Whalers | New England League | , | |
| Steve Brodie | brodie001wal | 1904 | 5/14-6/19 | Troy Trojans | New York State League | , | |
| Steve Brodie | brodie001wal | 1904 | 7/8-8/23 | Lebanon | Tri-State League | , | |
| Steve Brodie | brodie001wal | 1904 | 8/5-9/17 | Binghamton Bingoes | New York State League | , | |
| Michael Brophy | brophy000mic | 1904 | Kingston Colonials | Hudson River League | , | ||
| Frederick Broshard | brosha001f-- | 1904 | 5/28- | Cloudersport PA | Independent | , | |
| Frederick Broshard | brosha001f-- | 1904 | 8/24-9/8 | Coudersport | Southern Tier League | , | |
| Art Brouthers | brouth001art | 1904 | 4/20-7/8 | Toledo Mud Hens | American Association | , | |
| Dan Brouthers | brouth001den | 1904 | 117 g. | Poughkeepsie Colts | Hudson River League | , | |
| Dan Brouthers | brouth001den | 1904 | New York | National League | New York, NY | ||
| Brown | brown-219--- | 1904 | 8/27 | Nashua | New England League | , | |
| Brown | brown-248--- | 1904 | 9/16 | Rochester Bronchos | Eastern League | , | |
| Brown | brown-001ric | 1904 | Topeka Saints | Missouri Valley League | , | ||
| Brown | brown-139--- | 1904 | San Francisco | California State League | , | ||
| Brown | brown-264--- | 1904 | 8/21 | Olympia Senators | Southwest Washington League | , | |
| Brown | brown-030--- | 1904 | Johnstown Johnnies | Pennsylvania League | , | ||
| Brown | brown-071--- | 1904 | 6/25 | Anniston | Tennessee-Alabama League | , | |
| Brown | 1904 | 79 g. | Warren OH | Independent | , | ||
| Brown | 1904 | 29 g. | Akron OH | Independent | , | ||
| Brown | 1904 | 5 g. | Niles OH | Independent | , | ||
| Babe Brown | brown-004har | 1904 | 4/26-7/30 | New Orleans Pelicans | Southern Association | , | |
| Babe Brown | brown-004har | 1904 | 8/17-8/27 | Shreveport Pirates | Southern Association | , | |
| Bob Brown | brown-027rob | 1904 | 5/8-9/4 | Aberdeen Pippins | Southwest Washington League | , | |
| Buster Brown | brown-008cha | 1904 | 6/9-9/25 | Omaha Rangers | Western League | , | |
| Clarence Brown | 1904 | 29 g. | Akron OH | Independent | , | ||
| D. D. Brown | brown-002d-- | 1904 | 5/16- | 2 g. | Columbia | Tennessee-Alabama League | , |
| Dick Brown | brown-001ric | 1904 | 5/19- | Grand Forks Forkers | Northern League | , | |
| Dick Brown | brown-001ric | 1904 | 27 g. | Topeka Saints | Missouri Valley League | , | |
| Dick Brown | brown-001ric | 1904 | Grand Forks Forkers | Northern League | , | ||
| Fred Brown | brown-004fre | 1904 | 5/1-5/31 | Jersey City Skeeters | Eastern League | , | |
| Fred Brown | brown-004fre | 1904 | Sacramento | California State League | , | ||
| Fred Brown | brown-004fre | 1904 | 6/4- | Nashua | New England League | , | |
| Fred Brown | brown-004fre | 1904 | -9/17 | Haverhill Hustlers | New England League | , | |
| Gideon Brown | brown-001gid | 1904 | 7/8-7/22 | Lawrence Colts | New England League | , | |
| James Brown | brown-003jam | 1904 | 4/26-8/15 | Memphis Egyptians | Southern Association | , | |
| John Brown | brown-007jac | 1904 | 5/3-6/17 | Camden | Tri-State League | , | |
| Loren Brown | brown-001lor | 1904 | Guthrie Blues | Southwestern League | , | ||
| Mordecai Brown | brown-001mor | 1904-12 | Chicago | National League | Chicago, IL | ||
| Rollo Brown | brown-003rol | 1904 | preseason | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |
| Rollo Brown | brown-003rol | 1904 | +5/11-7/9+ | Ottumwa Standpatters | Iowa League | , | |
| Rollo Brown | brown-003rol | 1904 | +7/28+ | 45 g. | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , |
| Sam Brown | brown-003sam | 1904 | 4/20-9/19 | Toledo Mud Hens | American Association | , | |
| Stub Brown | brown-001stu | 1904 | +7/27+ | Midland MD | Independent | , | |
| Stub Brown | brown-001stu | 1904 | +8/17+ | Cambridge MD | Independent | , | |
| Tom Brown | brown-012tho | 1904 | +8/20+ | Umpire | Pacific Coast League | , | |
| George Brownell | browne003geo | 1904 | 44 g. | Akron OH | Independent | , | |
| Lou Bruce | bruce-001lou | 1904 | 5/3-6/18 | Wilmington Peaches | Tri-State League | , | |
| Lou Bruce | bruce-001lou | 1904 | 6/22-10/10 | Philadelphia | American League | Philadelphia, PA | |
| Lou Bruce | bruce-001lou | 1904 | 8/11-9/12 | Toronto Maple Leafs | Eastern League | , | |
| Frank Bruggeman | brugge001fra | 1904 | 5/7-9/5 | Marshalltown Grays | Iowa League | , | |
| William Bruggeman | brugge001--- | 1904 | Pine Bluff Lumbermen | Cotton States League | , | ||
| Will Bruner | bruner003wil | 1904 | 4/27 | Louisville Colonels | American Association | , | |
| Will Bruner | bruner003wil | 1904 | 5/16-7/14+ | Knoxville | Tennessee-Alabama League | , | |
| Brush | brush-003--- | 1904 | +6/5-6/15+ | Waterloo Microbes | Iowa League | , | |
| Ed Bruyette | bruyet001edw | 1904 | +4/26-9/8+ | Salt Lake City Elders | Pacific National League | , | |
| Bryan | bryan-004--- | 1904 | 1 g. | Sheffield | Tennessee-Alabama League | , | |
| Clarence Bryan | bryan-003cla | 1904 | 5/16-8/20 | Chattanooga | Tennessee-Alabama League | , | |
| Frank Bryan | bryan-001fra | 1904 | 416 ab | Greenville Cotton Pickers | Cotton States League | , | |
| Henry Bryant | bryant001low | 1904 | 5/25- | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |
| Henry Bryant | bryant001low | 1904 | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | ||
| George Bubser | bubser001geo | 1904 | no g. | Duluth White Sox | Northern League | , | |
| George Bubser | bubser001geo | 1904 | Chic.-Indep | Independent | , | ||
| George Bubser | bubser001geo | 1904 | no g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| George Bubser | bubser001geo | 1904 | +8/14+ | Kenosha WI | Semi-professional | , | |
| Frank Buchanan | buchan001fra | 1904 | 5/17- | 3 g. | Decatur | Tennessee-Alabama League | , |
| Jim Buchanan | buchan002jam | 1904 | 56 g. | Oakland Oaks | Pacific Coast League | , | |
| Al Buckenberger | bucken001al- | 1904 | Boston | National League | Boston, MA | ||
| Buckner | 1904 | +6/12+ | CubanXGiants | Independent | , | ||
| Michael Bucks | bucks-001mic | 1904 | Fort Scott Giants | Missouri Valley League | , | ||
| Percy Buckwalter | buckwa001per | 1904 | +7/13+ | Lisbon ND | Independent | , | |
| Percy Buckwalter | buckwa001per | 1904 | 7/18-8/13 | Fargo | Northern League | , | |
| Charlie Buelow | buelow001cha | 1904 | 122 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| Fritz Buelow | buelow001fre | 1904 | 42 g. | Detroit | American League | Detroit, MI | |
| Fritz Buelow | buelow001fre | 1904 | 42 g. | Cleveland | American League | Cleveland, OH | |
| Jack Bufka | bufka-001joh | 1904 | 5/14-7/18 | Grand Rapids Orphans | Central League | , | |
| Jack Bufka | bufka-001joh | 1904 | 8/15-9/11 | Grand Rapids Orphans | Central League | , | |
| Buhmaier | buhmai000--- | 1904 | +6/27+ | Massillon OH | Independent | , | |
| Ellerslie Bullard | bullar001--- | 1904 | Anni.-So RR | Independent | , | ||
| Ellerslie Bullard | bullar001--- | 1904 | 6/6-6/10+ | Anniston | Tennessee-Alabama League | , | |
| Ellerslie Bullard | bullar001--- | 1904 | Anniston | Tennessee-Alabama League | , | ||
| John Bunton | bunton001joh | 1904 | 65 g. | Sedalia Goldbugs | Missouri Valley League | , | |
| John Bunyan | bunyan001joh | 1904 | Hartford Senators | Connecticut State League | , | ||
| John Bunyan | bunyan001joh | 1904 | Meriden Silverites | Connecticut State League | , | ||
| Thomas Burbage | burbag001tho | 1904 | 4/30-9/2 | Lowell Tigers | New England League | , | |
| Burch | burch-008--- | 1904 | 5 g. | Springfield Midgets | Missouri Valley League | , | |
| Al Burch | burch-001alb | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| J. Burch | 1904 | Wheeling Stogies | Central League | , | |||
| Fred Burchell | burche001fre | 1904 | 4/29-9/27 | Baltimore Orioles | Eastern League | , | |
| Peter Burg | burg--001pet | 1904 | 4/30-7/31 | Grand Rapids Orphans | Central League | , | |
| Peter Burg | burg--001pet | 1904 | Chic.-Gunther | Independent | , | ||
| Peter Burg | burg--001pet | 1904 | 8/- | 22 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , |
| Burham | burham002--- | 1904 | 8/17 | Wellsville Oil Drillers | Southern Tier League | , | |
| Burke | 1904 | 18 g. | Findlay OH | Independent | , | ||
| Frank Burke | burke-002fra | 1904 | Meriden Silverites | Connecticut State League | , | ||
| James Burke | burke-101--- | 1904 | Coatesville PA | Independent | , | ||
| James Burke | burke-101--- | 1904 | 8/- | Elmira | Southern Tier League | , | |
| James Burke | 1904 | +8/3-9/5 | Umpire | South Atlantic League | , | ||
| Jimmy Burke | burke-004jam | 1904 | 118 g. | St. Louis | National League | St. Louis, MO | |
| John Burke | burke-004joh | 1904 | St. Bonaventure | College | , | ||
| John Burke | burke-004joh | 1904 | 6/10-9/28 | Newark Sailors | Eastern League | , | |
| Joseph Burke | burke-003jos | 1904 | 6/22-7/10 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Joseph Burke | burke-003jos | 1904 | 8/5-8/15 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Joseph Burke | burke-001jos | 1904 | +6/17+ | 5 g. | Bessemer | Tennessee-Alabama League | , |
| Patrick Burke | burke-001pat | 1904 | Brooklyn-s-p | Semi-professional | , | ||
| Patrick Burke | burke-001pat | 1904 | 8/25-9/17 | Utica Pent-Ups | New York State League | , | |
| Thomas Burke | 1904 | Montpelier-Barre | Northern New York League | , | |||
| Burkett | burket005--- | 1904 | 9/27 | Rochester Bronchos | Eastern League | , | |
| Jesse Burkett | burket001jes | 1904 | St. Louis | American League | St. Louis, MO | ||
| Luther Burleson | burles002lut | 1904 | +4/22-5/25+ | Trinity Univ. | College | , | |
| Luther Burleson | burles002lut | 1904 | 7/28-8/15 | Corsicana Oil Citys | Texas League | , | |
| Arthur Burman | burman001art | 1904 | 5/7-9/5 | Keokuk Indians | Iowa League | , | |
| Fred Burnam | burnam001fre | 1904 | no g. | Nashville Volunteers | Southern Association | , | |
| Fred Burnam | burnam001fre | 1904 | Natchez Indians | Cotton States League | , | ||
| Fred Burnam | burnam001fre | 1904 | 29 g. | Canton | Delta League | , | |
| Walter Burnham | burnha002wal | 1904 | 4/29-9/28 | Newark Sailors | Eastern League | , | |
| Burns | 1904 | 5 g. | Findlay OH | Independent | , | ||
| Burns | 1904 | +5/17+ | Hartford Senators | Connecticut State League | , | ||
| Burns | burns-034--- | 1904 | 52 g. | Meriden Silverites | Connecticut State League | , | |
| Billy Burns | burns-001wil | 1904 | 17 g. | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Edward Burns | burns-001edw | 1904 | 58 g. | Kingston Colonials | Hudson River League | , | |
| Gene Burns | burns-001eug | 1904 | 5/2-6/9 | Houston Wanderers | South Texas League | , | |
| Gene Burns | burns-001eug | 1904 | 6/28-7/10 | San Antonio Bronchos | South Texas League | , | |
| Gene Burns | burns-001eug | 1904 | 7/12-9/2 | Galveston Sand Crabs | South Texas League | , | |
| Jack Burns | burns-007joh | 1904 | - 4/22 | 4 g. | Detroit | American League | Detroit, MI |
| Jack Burns | burns-007joh | 1904 | 4/26-9/19 | Toledo Mud Hens | American Association | , | |
| Jack Burns | burns-010joh | 1904 | +6/19+ | Fargo | Northern League | , | |
| James Burns | 1904 | 5/6-6/20+ | Umpire | New York State League | , | ||
| James Burns | 1904 | Umpire | Hudson River League | , | |||
| James Burns | 1904 | Umpire | Western League | , | |||
| John Burns | burns-001joh | 1904 | 51 g. | Clarksdale | Delta League | , | |
| Mike Burns | burns-001mic | 1904 | 19 g. | San Antonio Bronchos | South Texas League | , | |
| Frank Burrell | burrel001bus | 1904 | 4/30-9/19 | New Bedford Whalers | New England League | , | |
| Harry Burrell | burrel001har | 1904 | Alexandria SD | Independent | , | ||
| Harry Burrell | burrel001har | 1904 | 7/21-8/21 | Umpire | Iowa League | , | |
| Leland Burrell | burrel000lel | 1904 | 4/30-5/21 | Houston Wanderers | South Texas League | , | |
| Leland Burrell | burrel000lel | 1904 | 5/22-9/2 | San Antonio Bronchos | South Texas League | , | |
| Lennius Burrell | burrel001len | 1904 | 6/29-9/10 | Elmira | Southern Tier League | , | |
| Lennius Burrell | burrel001len | 1904 | Syracuse Univ | College | , | ||
| Burrill | 1904 | Syracuse Univ. | College | , | |||
| Burrill | 1904 | Elmira NY | Independent | , | |||
| William Burroughs | 1904 | W. L. Waldrons NJ | Independent | , | |||
| Frank Burson | burson001fra | 1904 | +5/11-9/5 | Fort Dodge Gypsum Eaters | Iowa League | , | |
| Burt | burt--006--- | 1904 | +7/30-8/20 | Chattanooga | Tennessee-Alabama League | , | |
| Danny Burt | burt--001dan | 1904 | 120 g. | Savannah Pathfinders | South Atlantic League | , | |
| Harry Burton | burton007--- | 1904 | Butte MT | Independent | , | ||
| Harry Burton | burton007--- | 1904 | 15 g. | Crookston Crooks | Northern League | , | |
| Earl Burwell | burwel001ear | 1904 | 5/9 | Ottumwa Standpatters | Iowa League | , | |
| Earl Burwell | burwel001ear | 1904 | 5/27-6/17 | Keokuk Indians | Iowa League | , | |
| Henry Busch | busch-001hen | 1904 | 4/26-9/25 | Montgomery Senators | Southern Association | , | |
| Platt Bush | bush--000pla | 1904 | Sault Ste. Marie | Independent | , | ||
| Alfred Bushey | bushey001alf | 1904 | 5/2-9/17 | Lowell Tigers | New England League | , | |
| Fred Businsky | 1904 | 19 g. | Warren OH | Independent | , | ||
| Charley Busse | busse-001car | 1904 | Kingston Colonials | Hudson River League | , | ||
| Harry Bussey | bussey001har | 1904 | 81 g. | Augusta Tourists | South Atlantic League | , | |
| Harry Bussey | bussey001har | 1904 | 8/9-9/24 | Nashville Volunteers | Southern Association | , | |
| Harvey Bussey | bussey002har | 1904 | 5/6-6/3 | Binghamton Bingoes | New York State League | , | |
| Ike Butler | butler001isa | 1904 | Portland Browns | Pacific Coast League | , | ||
| J. W. Butler | butler001j-- | 1904 | 71 g. | Clarksdale | Delta League | , | |
| Joe Butler | butler018--- | 1904 | +6/3+ | So Boston HS | High School | , | |
| John Butler | butler002joh | 1904 | 4/20-9/17 | Kansas City Blues | American Association | , | |
| John Butler | butler002joh | 1904 | 12 g. | St. Louis | National League | St. Louis, MO | |
| Peck Butler | butler001o-- | 1904 | 27 g. | Augusta Tourists | South Atlantic League | , | |
| Peck Butler | butler001o-- | 1904 | 9/6-9/24 | Memphis Egyptians | Southern Association | , | |
| Will Butler | butler004wil | 1904 | 4/27-8/2 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Will Butler | butler004wil | 1904 | 8/10-8/15 | Dallas Giants | Texas League | , | |
| Edward Butman | butman001edw | 1904 | 93 ab | Newburgh Taylor-mades | Hudson River League | , | |
| Edward Butman | butman001edw | 1904 | 7/1-8/4 | Hornellsville Maple Cities | Southern Tier League | , | |
| Edward Butman | butman001edw | 1904 | 8/6-8/15 | Binghamton Bingoes | New York State League | , | |
| John Buttermore | butter001joh | 1904 | Kingston Colonials | Hudson River League | , | ||
| Bill Byers | byers-002jam | 1904 | 4/15-6/4 | St. Louis | National League | St. Louis, MO | |
| Bill Byers | byers-002jam | 1904 | 7/4-9/28 | Baltimore Orioles | Eastern League | , | |
| Herbert Byram | 1904 | Princeton Univ. | College | , | |||
| Bobby Byrne | byrne-003rob | 1904 | 26 g. | Fort Scott Giants | Missouri Valley League | , | |
| Jim Byrnes | byrnes002jam | 1904 | San Francisco | California State League | , | ||
| Jim Byrnes | byrnes002jam | 1904 | Oakland Oaks | Pacific Coast League | , | ||
| Cabaniss | 1904 | 7/26-8/2 | Paris Parasites/Ardmore Territorians | Texas League | , | ||
| Frank Cable | cable-001fra | 1904 | 4/27-9/24 | Denver Grizzlies | Western League | , | |
| Ralph Cadwalader | cadwal001ral | 1904 | 4/29-9/23 | Sioux City Soos | Western League | , | |
| Ben Caffyn | caffyn001ben | 1904 | 120 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| James Cahill | cahill004--- | 1904 | 7/18- | 3 g. | Chattanooga | Tennessee-Alabama League | , |
| John Cahill | cahill001joh | 1904 | Galena IL | , | |||
| Ralph Caldwell | caldwe002ral | 1904 | 9/10- | 6 g. | Philadelphia | National League | Philadelphia, PA |
| Jack Calhoun | calhou002joh | 1904 | 4/30-9/17 | Haverhill Hustlers | New England League | , | |
| Evelyn Califf | califf001elm | 1904 | 4/29-6/23+ | Salem Raglands | Oregon State League | , | |
| Callahan | 1904 | 5/20 | Dayton Veterans | Central League | , | ||
| Jack Callahan | callah025--- | 1904 | 8/12-9/28 | Rochester Bronchos | Eastern League | , | |
| Jim Callahan | callah004jam | 1904 | 17 g. | Niles OH | Independent | , | |
| Jimmy Callahan | callah002jam | 1904 | Chicago | American League | Chicago, IL | ||
| Eugene? Calloway | callow002--- | 1904 | +5/30+ | Waterloo Microbes | Iowa League | , | |
| Camden | 1904 | 8/5 | Wheeling Stogies | Central League | , | ||
| Dan Cameron | camero001dan | 1904 | +6/27-8/18 | Decatur | Tennessee-Alabama League | , | |
| Don Cameron | camero003don | 1904 | 5/19- | Superior Longshoremen | Northern League | , | |
| Don Cameron | camero003don | 1904 | 50 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| Louis Cameron | camero001lou | 1904 | 5/27 | Knoxville | Tennessee-Alabama League | , | |
| Howie Camnitz | camnit001sam | 1904 | 19 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Howie Camnitz | camnit001sam | 1904 | 4/22- | 10 g. | Pittsburgh | National League | Pittsburgh, PA |
| Camp | camp--011--- | 1904 | Centralia HS | High School | , | ||
| Camp | camp--011--- | 1904 | 7/3-8/21 | Centralia Midgets | Southwest Washington League | , | |
| Count Campau | campau001cha | 1904 | 5/6-9/8 | Binghamton Bingoes | New York State League | , | |
| A. B. Campbell | 1904 | Oswego-s-pro | Semi-professional | , | |||
| A. B. Campbell | 1904 | 8/18 | Utica Pent-Ups | New York State League | , | ||
| Bill Campbell | campbe001wil | 1904 | 5/8-6/26 | Aberdeen Pippins | Southwest Washington League | , | |
| Bill Campbell | campbe001wil | 1904 | Tacoma Tigers | Pacific Coast League | , | ||
| Billy Campbell | campbe004wil | 1904 | 4/20-9/19 | Louisville Colonels | American Association | , | |
| C. A. Campbell | 1904 | Juneau | , | ||||
| Chester Campbell | campbe001che | 1904 | Sacramento | California State League | , | ||
| Chester Campbell | campbe001che | 1904 | Portland Browns | Pacific Coast League | , | ||
| Frank Campbell | 1904 | , | |||||
| Freemont Campbell | 1904 | Juneau | , | ||||
| Jack Campbell | campbe005jac | 1904 | Vermont League | , | |||
| Jack Campbell | campbe005jac | 1904 | 9/8-9/17 | Nashua | New England League | , | |
| Sullivan Campbell | campbe001sul | 1904 | Fredonia KS | Independent | , | ||
| Tom Campbell | 1904 | Augusta Tourists | South Atlantic League | , | |||
| Tommy Campbell | campbe000tom | 1904 | 5/3-9/10 | Wilmington Peaches | Tri-State League | , | |
| John Campion | campio001--- | 1904 | 5/21-6/1 | Minneapolis Millers | American Association | , | |
| Jim Canavan | canava001jim | 1904 | 100 g. | New Haven Blues | Connecticut State League | , | |
| Winburn Cannell | cannel000win | 1904 | 6/24-7/4 | Nashua | New England League | , | |
| Wirt Cannell | cannel001vir | 1904 | 4/14- | 100 g. | Boston | National League | Boston, MA |
| George Cannon | cannon001elm | 1904 | 5/8-9/8 | Wheeling Stogies | Central League | , | |
| Joe Cantillon | cantil001jos | 1904 | 4/20-9/20 | Milwaukee Brewers | American Association | , | |
| Arthur Carbiener | carbie001art | 1904 | 4/29-9/11 | Fort Wayne Railroaders | Central League | , | |
| George Carey | carey-002geo | 1904 | 4/29-9/28 | Rochester Bronchos | Eastern League | , | |
| Chick Cargo | cargo-001cha | 1904 | 5/6-9/18 | Albany Senators | New York State League | , | |
| Fred Carisch | carisc001fre | 1904 | 5/31-7/15 | Jersey City Skeeters | Eastern League | , | |
| Fred Carisch | carisc001fre | 1904 | 37 g. | Pittsburgh | National League | Pittsburgh, PA | |
| Carleton | carlet004--- | 1904 | 9/7 | Nashua | New England League | , | |
| Edwin Carlin | 1904 | Dickinson Col | College | , | |||
| Carline | carlin006--- | 1904 | 7/23 | Providence Grays | Eastern League | , | |
| Walter Carlisle | carlis001wal | 1904 | 48 g. | Crookston Crooks | Northern League | , | |
| Walter Carlisle | carlis001wal | 1904 | +6/26-8/11+ | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Carney | carney019--- | 1904 | 7/8 | Concord Marines | New England League | , | |
| Bill Carney | carney002wil | 1904 | 9 g. | Fort Scott Giants | Missouri Valley League | , | |
| Bill Carney | carney002wil | 1904 | 86 g. | Spokane Indians | Pacific National League | , | |
| Bill Carney | carney002wil | 1904 | 8/22 | Chicago | National League | Chicago, IL | |
| Jack Carney | carney002joh | 1904 | 4/30-7/6 | Nashua | New England League | , | |
| Carpenter | 1904 | Saugerties | Hudson River League | , | |||
| William Carpenter | 1904 | 55 g. | MLB Umpire | American League | , | ||
| William Carpenter | 1904 | 87 g. | MLB Umpire | National League | , | ||
| Charlie Carr | carr--001cha | 1904 | 92 g. | Detroit | American League | Detroit, MI | |
| Charlie Carr | carr--001cha | 1904 | 32 g. | Cleveland | American League | Cleveland, OH | |
| Hart Carr | carr--001ham | 1904 | 5/6-5/7 | Ilion Typewriters | New York State League | , | |
| Hart Carr | carr--001ham | 1904 | 7/1-8/19 | Hornellsville Maple Cities | Southern Tier League | , | |
| John Carr | 1904 | +6/8+ | Durh.-Doctors | Independent | , | ||
| John Carr | carr--003joh | 1904 | 4/20-9/20 | Indianapolis Indians | American Association | , | |
| Lew Carr | carr--001lew | 1904 | 4/29-9/28 | Toronto Maple Leafs | Eastern League | , | |
| Sidney Carr | carr--001sid | 1904 | 7/8-7/29+ | Wellsville Oil Drillers | Southern Tier League | , | |
| Carrick | carric001wil | 1904 | 5/1+ | Williamsport Millionaires | Tri-State League | , | |
| Bill Carrick | carric001wil | 1904 | 4/30- | Haverhill Hustlers | New England League | , | |
| Bill Carrick | carric001wil | 1904 | Manchester | New England League | , | ||
| Bill Carrick | carric001wil | 1904 | -9/19 | Fall River Indians | New England League | , | |
| Bill Carrigan | carrig001wil | 1904 | Holy Cross Col. | College | , | ||
| Frank Carriveau | carriv001fra | 1904 | 5/19- | Grand Forks Forkers | Northern League | , | |
| Frank Carriveau | carriv001fra | 1904 | Rutland | Northern New York League | , | ||
| Frank Carroll | carrol001fra | 1904 | 4/30- | Nashua | New England League | , | |
| Frank Carroll | carrol001fra | 1904 | -6/9 | Lawrence Colts | New England League | , | |
| Joseph Carroll | 1904 | Paterson Intruders | Hudson River League | , | |||
| Fred Carson | 1904 | U. Michigan | College | , | |||
| Fred Carson | 1904 | Grand Rapids Orphans | Central League | , | |||
| Bobby Carter | carter003rob | 1904 | 4/24-9/25 | Omaha Rangers | Western League | , | |
| Charles Carter | carter005cha | 1904 | 4/21-7/14 | Montgomery Senators | Southern Association | , | |
| Charles Carter | carter005cha | 1904 | 9/5-9/6 | Montgomery Senators | Southern Association | , | |
| Curtis Carter | carter004cha | 1904 | 51 g. | Topeka Saints | Missouri Valley League | , | |
| Nick Carter | carter002con | 1904 | Syracuse Stars | New York State League | , | ||
| Cartwright | 1904 | 5/15 | Fort Worth Panthers | Texas League | , | ||
| Walter Cartwright | cartwr001wal | 1904 | +5/15+ | 7 g. | Portland Browns | Pacific Coast League | , |
| Walter Cartwright | cartwr001wal | 1904 | 6/2-7/4 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Bob Caruthers | caruth001bob | 1904 | 4/24-9/25 | Umpire | Western League | , | |
| Charlie Case | case--001cha | 1904 | 16 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Charlie Case | case--001cha | 1904 | 18 g. | Pittsburgh | National League | Pittsburgh, PA | |
| W. H. Case | case--002w-- | 1904 | 5/9-8/31 | Burlington River Rats | Iowa League | , | |
| James Casey | casey-002jam | 1904 | 136 g. | Chicago | National League | Chicago, IL | |
| Patrick Casey | casey-001pat | 1904 | 6 ab | Pine Bluff Lumbermen | Cotton States League | , | |
| Pearl Casey | casey-001pea | 1904 | Tacoma Tigers | Pacific Coast League | , | ||
| Harry Cassady | cassad001har | 1904 | 84 g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| Harry Cassady | cassad001har | 1904 | 15 g. | Youngstown OH | Independent | , | |
| Harry Cassady | cassad001har | 1904 | 8/8- | 12 g. | Pittsburgh | National League | Pittsburgh, PA |
| Charles Cassell | 1904 | +6/10+ | Wellington OH | Independent | , | ||
| Charles Cassell | 1904 | +8/25+ | Chardon OH | Independent | , | ||
| Howdy Cassiboine | cassib001how | 1904 | preseason | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Howdy Cassiboine | cassib001how | 1904 | Davenport River Rats | Illinois-Indiana-Iowa League | , | ||
| Howdy Cassiboine | cassib001how | 1904 | +6/21-9/5 | Oskaloosa Quakers | Iowa League | , | |
| Cassidy | 1904 | 5/1 | Camden | Tri-State League | , | ||
| Cassidy | cassid007--- | 1904 | 31 g. | Springfield Ponies | Connecticut State League | , | |
| Cassidy | 1904 | 15 g. | Youngstown OH | Independent | , | ||
| Benny Cassidy | cassid001ber | 1904 | 31 g. | Springfield Ponies | Connecticut State League | , | |
| Benny Cassidy | cassid001ber | 1904 | 7/2-9/17 | Nashua | New England League | , | |
| Joe Cassidy | cassid001jos | 1904 | 4/18- | 152 g. | Washington | American League | Washington, DC |
| Pete Cassidy | cassid003pet | 1904 | 4/29-8/23 | Jersey City Skeeters | Eastern League | , | |
| Benjamin Castle | castle001ben | 1904 | Clev.-Castle AC | Independent | , | ||
| Benjamin Castle | castle001ben | 1904 | +8/21+ | Forest City | Independent | , | |
| Roy Castleton | castle002roy | 1904 | 7/30 | Salt Lake City Elders | Pacific National League | , | |
| Lou Castro | castro001lou | 1904 | 112 g. | Portland Browns | Pacific Coast League | , | |
| Eli Cates | cates-002eli | 1904 | 84 g. | Leavenworth Orioles | Missouri Valley League | , | |
| Tom Catterson | catter001tho | 1904 | Greenfield MA | Independent | , | ||
| Tom Catterson | catter001tho | 1904 | +7/2+ | Olneyville | Independent | , | |
| Dred Cavender | cavend001dre | 1904 | 442 ab | Pine Bluff Lumbermen | Cotton States League | , | |
| Ed Cermak | cermak001edw | 1904 | 4/30-9/2 | Galveston Sand Crabs | South Texas League | , | |
| Chadwick | chadwi001--- | 1904 | 2 g. | Decatur | Tennessee-Alabama League | , | |
| Charles Chalkley | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |||
| Chamberlain | 1904 | 5/22 | Dayton Veterans | Central League | , | ||
| Champlin | 1904 | 5/-6/15 | Kent OH | Independent | , | ||
| Champlin | 1904 | 9 g. | Chic. Junction OH | Independent | , | ||
| Chuck Chandler | chandl001cha | 1904 | 5/19- | 13 g. | Superior Longshoremen | Northern League | , |
| Robert Chandler | chandl002rob | 1904 | 74 g. | Charleston Sea Gulls | South Atlantic League | , | |
| Robert Chandler | chandl002rob | 1904 | Augusta Tourists | South Atlantic League | , | ||
| Robert Chandler | chandl002rob | 1904 | Macon Highlanders | South Atlantic League | , | ||
| Arthur Chapin | chapin001a-- | 1904 | Paterson Intruders | Hudson River League | , | ||
| Arthur Chapin | chapin001a-- | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| Charles Chapman | chapma001cha | 1904 | Tufts College | College | , | ||
| Charles Chapman | chapma001cha | 1904 | 7/11-9/17 | Manchester | New England League | , | |
| Robert Chappelle | chappe001rob | 1904 | 79 g. | Jacksonville Jays | South Atlantic League | , | |
| William Chappelle | chappe002wil | 1904 | Ilion Typewriters | New York State League | , | ||
| Robert Charnier | charni001rob | 1904 | preseason | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Robert Charnier | charni001rob | 1904 | Burlington River Rats | Iowa League | , | ||
| Robert Charnier | charni001rob | 1904 | 7/1-8/31+ | Keokuk Indians | Iowa League | , | |
| Chase | chase-020--- | 1904 | 7/1-8/18 | Addison White Sox | Southern Tier League | , | |
| Hal Chase | chase-002har | 1904 | 190 g. | Los Angeles Angels | Pacific Coast League | , | |
| Harry Chase | chase-003har | 1904 | 5/7- | Manchester | New England League | , | |
| Harry Chase | chase-003har | 1904 | -9/17 | Lowell Tigers | New England League | , | |
| Cheatham | cheath000--- | 1904 | +5/14-9/17+ | Rich.-Brownies | Twin City League | , | |
| Gib Cheatum | cheatu001--- | 1904 | +5/11+ | Kingman KS | Independent | , | |
| Charlie Chech | chech-001cha | 1904 | 4/20-9/13 | St. Paul Saints | American Association | , | |
| Harry Cheek | cheek-001har | 1904 | 5/19- | 38 g. | Grand Forks Forkers | Northern League | , |
| Harry Cheek | cheek-001har | 1904 | 38 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Robert Chellew | chelle001r-- | 1904 | Carlisle | Pennsylvania League | , | ||
| Robert Chellew | chelle001r-- | 1904 | 8/9 | Harrisburg Senators | Tri-State League | , | |
| William Cherry | cherry000bil | 1904 | 6/23-6/24 | Evansville River Rats | Central League | , | |
| William Cherry | cherry000bil | 1904 | FtWa-Shamrocks | Independent | , | ||
| Walter Chilcott | chilco001wal | 1904 | Pottsville PA | Independent | , | ||
| Walter Chilcott | chilco001wal | 1904 | 6/16-8/17 | Lawrence Colts | New England League | , | |
| Cupid Childs | childs001cla | 1904 | 6/27-7/10 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Cupid Childs | childs001cla | 1904 | 7/12-9/17 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Louis Childs | childs002lou | 1904 | 44 g. | Charleston Sea Gulls | South Atlantic League | , | |
| Louis Childs | childs002lou | 1904 | 9/14-9/21 | Atlanta Crackers | Southern Association | , | |
| Pete Childs | childs001geo | 1904 | 4/20-4/24 | Kansas City Blues | American Association | , | |
| Pete Childs | childs001geo | 1904 | 5/6-9/17 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Thomas Chinn | chinn-001tho | 1904 | 4/24-8/7 | St. Joseph Saints | Western League | , | |
| John Christian | christ003j-- | 1904 | 5/17 | Fort Wayne Railroaders | Central League | , | |
| John Christian | christ003j-- | 1904 | 8/20-9/11 | South Bend Greens | Central League | , | |
| Harold Christman | christ005har | 1904 | 4/27-8/13 | Fort Worth Panthers | Texas League | , | |
| Harold Christman | christ005har | 1904 | 8/16-9/2 | Galveston Sand Crabs | South Texas League | , | |
| Church | church007--- | 1904 | U. of Illinois | College | , | ||
| Church | church007--- | 1904 | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | ||
| Church | church007--- | 1904 | 7 g. | Topeka Saints | Missouri Valley League | , | |
| A. M. Church | 1904 | Colorado Springs Millionaires | Western League | , | |||
| Eddie Cicotte | cicott001edw | 1904 | Sault Ste. Marie | Northern Copper League | , | ||
| Bill Clancy | clancy002wil | 1904 | 5/6-9/28 | Montreal Royals | Eastern League | , | |
| Bill Clancy | clancy002wil | 1904 | 10 g. | Oakland Oaks | Pacific Coast League | , | |
| Charles Clancy | clancy001cha | 1904 | 23 g. | Holyoke Paperweights | Connecticut State League | , | |
| Clapp | clapp-001--- | 1904 | 5/16-5/24+ | Columbia | Tennessee-Alabama League | , | |
| Clapp | clapp-001--- | 1904 | +6/16+ | 7 g. | Bessemer | Tennessee-Alabama League | , |
| Clark | clark-001ler | 1904 | St. Paul Saints | American Association | , | ||
| Dad Clark | clark-002alf | 1904 | 127 g. | Salt Lake City Elders | Pacific National League | , | |
| Dick Clark | clark-001ric | 1904 | 34 g. | Dallas Giants | Texas League | , | |
| Dick Clark | clark-001ric | 1904 | 8/24-9/21 | Birmingham Barons | Southern Association | , | |
| George Clark | clark-002geo | 1904 | 5/9-9/25 | Des Moines Prohibitionists | Western League | , | |
| Ginger Clark | clark-006har | 1904 | 4/23-9/17 | Birmingham Barons | Southern Association | , | |
| Harry Clark | clark-004har | 1904 | 4/20-9/20 | Milwaukee Brewers | American Association | , | |
| James Clark | clark-014jam | 1904-05 | , | ||||
| John Clark | clark-128--- | 1904 | 7/3-7/17 | Centralia Midgets | Southwest Washington League | , | |
| John Clark | clark-001jl- | 1904 | 17 g. | Augusta Tourists | South Atlantic League | , | |
| Leroy Clark | clark-001ler | 1904 | 4/22-5/23 | St. Paul Saints | American Association | , | |
| Leroy Clark | clark-001ler | 1904 | 5/30- | Winnipeg Maroons | Northern League | , | |
| Leroy Clark | clark-001ler | 1904 | 8/20-9/19 | Toledo Mud Hens | American Association | , | |
| Ned Clark | clark-000ned | 1904 | Peddie Institute | Academy | , | ||
| Ned Clark | clark-000ned | 1904 | 5/28- | Cloudersport PA | Independent | , | |
| Ned Clark | clark-000ned | 1904 | 8/29-9/8 | Coudersport | Southern Tier League | , | |
| Orel Clark | clark-001ore | 1904 | 5/18-5/30 | Colorado Springs Millionaires | Western League | , | |
| Orel Clark | clark-001ore | 1904 | 7/9-9/25 | St. Joseph Saints | Western League | , | |
| Roy Clark | clark-002roy | 1904 | 115 g. | Bridgeport Orators | Connecticut State League | , | |
| Wilkie Clark | clark-001wil | 1904 | 4/21-9/25 | Montgomery Senators | Southern Association | , | |
| William Clark | clark-016wil | 1904 | 5/17-5/30 | Concord Marines | New England League | , | |
| William Clark | clark-016wil | 1904 | 47 g. | Meriden Silverites | Connecticut State League | , | |
| William Clark | clark-016wil | 1904 | Norwich Reds | Connecticut State League | , | ||
| Win Clark | clark-012wil | 1904 | 4/29-6/3 | Toronto Maple Leafs | Eastern League | , | |
| Win Clark | clark-012wil | 1904 | 6/7- | Concord Marines | New England League | , | |
| Win Clark | clark-012wil | 1904 | -9/17 | New Bedford Whalers | New England League | , | |
| Clarke | clark-001jl- | 1904 | 17 g. | Augusta Tourists | South Atlantic League | , | |
| Dad Clarke | clarke001dad | 1904 | Butte Miners/Fruit Pickers | Pacific National League | , | ||
| Dad Clarke | clarke001dad | 1904 | Salt Lake City Elders | Pacific National League | , | ||
| Dad Clarke | clarke001dad | 1904 | Springfield Hustlers | Illinois-Indiana-Iowa League | , | ||
| James Clarke | clarke002jam | 1904 | Hudson Marines | Hudson River League | , | ||
| Jay Clarke | clarke001jay | 1904 | 4/21-9/24 | Atlanta Crackers | Southern Association | , | |
| Josh Clarke | clarke002jos | 1904 | 4/24-9/25 | Des Moines Prohibitionists | Western League | , | |
| LeRoy Clarke | 1904-06 | , | |||||
| Walter Clarkson | clarks001wal | 1904 | 13 g. | New York | American League | New York, NY | |
| Bill Clay | clay--002fre | 1904 | 5/10-9/27 | York Penn Parks | Tri-State League | , | |
| Waldo Clay | clay--001wal | 1904 | 5/5-5/14 | Rochester Bronchos | Eastern League | , | |
| Waldo Clay | clay--001wal | 1904 | 5/27-6/18 | Newark Sailors | Eastern League | , | |
| Waldo Clay | clay--001wal | 1904 | 6/24-9/16 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Clayson | clayso000--- | 1904 | 21 g. | Kane OH | Independent | , | |
| Clayson | clayso000--- | 1904 | Sharon PA | Independent | , | ||
| Clayson | clayso000--- | 1904 | 8/18-8/19 | Wellsville Oil Drillers | Southern Tier League | , | |
| Harry Clayton | clayto001har | 1904 | 417 ab | Pine Bluff Lumbermen | Cotton States League | , | |
| Mark Clayton | clayto001mar | 1904 | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | ||
| William Clayton | clayto001wil | 1904 | Ardmore IT | Independent | , | ||
| William Clayton | clayto001wil | 1904 | 8/5-8/15 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Harry Claytor | clayto002hen | 1904 | +5/27+ | Winnipeg Maroons | Northern League | , | |
| James Cleary | cleary001jam | 1904 | 19 g. | Sharon PA | Independent | , | |
| James Cleary | cleary001jam | 1904 | 9/6-9/27 | Rochester Bronchos | Eastern League | , | |
| Wally Clement | clemen001wal | 1904 | 4/29-7/4 | Jersey City Skeeters | Eastern League | , | |
| Wally Clement | clemen001wal | 1904 | 8/6-9/28 | Jersey City Skeeters | Eastern League | , | |
| Clemons | clemon007--- | 1904 | 5/8-5/15 | Aberdeen Pippins | Southwest Washington League | , | |
| Zora Clevenger | 1904-06 | Univ. of Indiana | College | , | |||
| Billy Clingman | clingm001wil | 1904 | 4/23-7/7 | St. Paul Saints | American Association | , | |
| Billy Clingman | clingm001wil | 1904 | 7/9-9/19 | Toledo Mud Hens | American Association | , | |
| Matthew Cloonin | clooni000m-- | 1904 | 5/2 | New Bedford Whalers | New England League | , | |
| W. R. Cloyd | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |||
| Bill Clymer | clymer001wil | 1904 | 4/20-9/20 | Columbus Senators | American Association | , | |
| Otis Clymer | clymer001oti | 1904 | 4/30-9/28 | Buffalo Bisons | Eastern League | , | |
| John Clynes | clynes001jos | 1904 | +2/13-3/12+ | Santa Clara | College | , | |
| John Clynes | clynes001jos | 1904 | 4/30-5/1 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| John Clynes | clynes001jos | 1904 | 5/5-7/4 | Eugene Blues | Oregon State League | , | |
| John Clynes | clynes001jos | 1904 | San Jose | California State League | , | ||
| John Clynes | clynes001jos | 1904 | +9/4-9/25 | Portland Browns | Pacific Coast League | , | |
| Joseph Clynes | clynes001jos | 1904 | San Jose | California State League | , | ||
| Andy Coakley | coakle001and | 1904 | 8 g. | Philadelphia | American League | Philadelphia, PA | |
| Floyd Coates | coates001f-- | 1904 | Grand Forks Forkers | Northern League | , | ||
| Floyd Coates | coates001f-- | 1904 | 5/30-6/14 | Waterloo Microbes | Iowa League | , | |
| Floyd Coates | coates001f-- | 1904 | 6/27-9/5 | Oskaloosa Quakers | Iowa League | , | |
| Ty Cobb | cobb--001tyr | 1904 | 4/19- | 2 g.? | Augusta Tourists | South Atlantic League | , |
| Ty Cobb | cobb--001tyr | 1904 | 5/16-7/8 | Anniston | Tennessee-Alabama League | , | |
| Ty Cobb | cobb--001tyr | 1904 | +7/21+ | Sheffield | Tennessee-Alabama League | , | |
| Ty Cobb | cobb--001tyr | 1904 | 35 g. | Augusta Tourists | South Atlantic League | , | |
| Samuel Cobean | cobean001sam | 1904 | 4/30-9/20 | Grand Rapids Orphans | Central League | , | |
| Samuel Cobean | cobean001sam | 1904 | 8/28-9/6 | Evansville River Rats | Central League | , | |
| Jim Cockman | cockma001jam | 1904 | 4/29-9/23 | Newark Sailors | Eastern League | , | |
| E.E. Codding | coddin000ee- | 1904 | Sedalia Goldbugs | Missouri Valley League | , | ||
| Charles Coe | coe---002cha | 1904 | Hot Springs AR | Independent | , | ||
| Charles Coe | coe---002cha | 1904 | 8/9-8/10 | Sioux City Soos | Western League | , | |
| Charles Coe | coe---002cha | 1904 | +9/4-9/25+ | Grand Isl. NB | Independent | , | |
| Edward Coffey | coffey001edw | 1904 | 4/28- | South Bend Greens | Central League | , | |
| Edward Coffey | coffey001edw | 1904 | 7/18- | Coatesville | Pennsylvania League | , | |
| Edward Coffey | coffey001edw | 1904 | 9/10-9/15 | Louisville Colonels | American Association | , | |
| Edward Coffey | coffey001edw | 1904 | -9/28 | South Bend Greens | Central League | , | |
| Dick Cogan | cogan-001dic | 1904 | 415 ab | Paterson Intruders | Hudson River League | , | |
| Allan Coggins | coggin009--- | 1904 | +7/13-8/9+ | Asheville | Carolina Interstate League | , | |
| Charles Cogswell | cogswe003cha | 1904 | 4/28-8/18 | South Bend Greens | Central League | , | |
| Charles Cogswell | cogswe003cha | 1904 | 8/22-9/30 | Harrisburg Senators | Tri-State League | , | |
| Bernard Colburn | colbur001ber | 1904 | 4/30- | Lawrence Colts | New England League | , | |
| Bernard Colburn | colbur001ber | 1904 | Haverhill Hustlers | New England League | , | ||
| Bernard Colburn | colbur001ber | 1904 | -9/17 | Concord Marines | New England League | , | |
| Charles Cole | cole--003cha | 1904 | 5/19- | 43 g. | Grand Forks Forkers | Northern League | , |
| Charles Cole | cole--003cha | 1904 | +7/30-/9/5 | Waterloo Microbes | Iowa League | , | |
| Clarence Cole | cole--002cla | 1904 | 126 g. | Topeka Saints | Missouri Valley League | , | |
| James Coleman | colema004jam | 1904 | 60 g. | Brookhaven | Delta League | , | |
| James Coleman | colema004jam | 1904 | 46 g. | Jackson Senators | Delta League | , | |
| Cad Coles | coles-001cad | 1904 | Mt | , | |||
| Cap Collars | collar001cap | 1904 | +7/3+ | FW-Shamrocks | Independent | , | |
| Collester | 1904 | 6/8-6/10 | Utica Pent-Ups | New York State League | , | ||
| Jack Colligan | 1904 | 12 g. | Bridgeport Orators | Connecticut State League | , | ||
| Jack/Eddie? Colligan | collig002--- | 1904 | 104 ab | Poughkeepsie Colts | Hudson River League | , | |
| Collins | collin008--- | 1904 | +6/18-8/15 | Columbia | Tennessee-Alabama League | , | |
| Collins | 1904 | 6/24-8/1 | Binghamton Bingoes | New York State League | , | ||
| Collins | 1904 | 8/20-9/8 | Marion Oilworkers/Peoria Distillers | Central League | , | ||
| Eddie Collins | collin003edw | 1904-07 | Columbia Univ. | College | , | ||
| Edward Collins | collin002e-- | 1904 | +5/11-9/5 | Fort Dodge Gypsum Eaters | Iowa League | , | |
| John Collins | collin002joh | 1904 | 5/11- | 47+ g. | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , |
| John C.? Collins | 1904 | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |||
| Orth Collins | collin001ort | 1904 | 4/29-8/15 | Rochester Bronchos | Eastern League | , | |
| Orth Collins | collin001ort | 1904 | 6/1- | 5 g. | New York | American League | New York, NY |
| Jim Collopy | collop001jam | 1904 | 5/6-6/18 | Binghamton Bingoes | New York State League | , | |
| Jim Collopy | collop001jam | 1904 | Burlington VT | Independent | , | ||
| Paul Companion | compan001pau | 1904 | 4/26-7/10 | Omaha Rangers | Western League | , | |
| Paul Companion | compan001pau | 1904 | 9/8 | Omaha Rangers | Western League | , | |
| Edward Conahan | 1904 | +9/10+ | Umpire | Eastern League | , | ||
| James Conan | conan-000jam | 1904 | Jackson NY | Independent | , | ||
| Edward Conboy | conboy000edw | 1904 | 7/1- | Wellsville Oil Drillers | Southern Tier League | , | |
| William Condon | condon000bil | 1904 | +7/24+ | Helena MT | Independent | , | |
| James Conevery | conave001j-- | 1904 | Coudersport PA | Independent | , | ||
| James Conevery | conave001j-- | 1904 | 7/27-8/10 | Wellsville Oil Drillers | Southern Tier League | , | |
| James Conevery | conave001j-- | 1904 | 9/1-9/8 | Coudersport | Southern Tier League | , | |
| James Conevery | conave001j-- | 1904-05 | Syracuse Univ. | College | , | ||
| Bunk Congalton | congal001wil | 1904 | 4/24-9/25 | Colorado Springs Millionaires | Western League | , | |
| Charles Conklin | conkli002cha | 1904 | 5/16-6/1+ | Knoxville | Tennessee-Alabama League | , | |
| Charles Conklin | conkli002cha | 1904 | Greensburg IN | Independent | , | ||
| Frank Conlin | conlin001fra | 1904 | Leavenworth KS | Independent | , | ||
| Bert Conn | conn--001alb | 1904 | 4/30-9/28 | Providence Grays | Eastern League | , | |
| Frank Connaughton | connau001fra | 1904 | 4/20-4/24 | Toledo Mud Hens | American Association | , | |
| Frank Connaughton | connau001fra | 1904 | 5/2-9/16 | Haverhill Hustlers | New England League | , | |
| Jerry Connell | connel001jer | 1904 | New Haven Blues | Connecticut State League | , | ||
| Ralph Connell | connel039--- | 1904 | Herington KS | Independent | , | ||
| Florence Connelly | connel000flo | 1904 | 6/29-8/ | Elmira | Southern Tier League | , | |
| Harry Connelly | connel001har | 1904 | Hartford Senators | Connecticut State League | , | ||
| Harry Connelly | connel001har | 1904 | Norwich Reds | Connecticut State League | , | ||
| Conners | 1904 | Dayton Veterans | Central League | , | |||
| Conners | 1904 | 5/27- | 37 g. | Urbana OH | Independent | , | |
| Conners | 1904 | Coshocton OH | Independent | , | |||
| Robert Connery | conner001rob | 1904 | 4/24-9/25 | Des Moines Prohibitionists | Western League | , | |
| D. B. Connett | connet001d-- | 1904 | 31 g. | Columbia Skyscrapers | South Atlantic League | , | |
| Harry Connolly | 1904 | Norwich Reds | Connecticut State League | , | |||
| Harry Connolly | 1904 | Holyoke Paperweights | Connecticut State League | , | |||
| Patrick Connolly | connol001pat | 1904 | 5/2- | 1390 g. | New Bedford Whalers | New England League | , |
| Patrick Connolly | connol001pat | 1904 | -9/16 | Haverhill Hustlers | New England League | , | |
| Connor | connor045--- | 1904 | 4/29-5/1 | Montreal Royals | Eastern League | , | |
| Jim Connor | connor001jim | 1904 | 4/30-7/27 | Providence Grays | Eastern League | , | |
| Jim Connor | connor001jim | 1904 | 8/30-9/28 | Providence Grays | Eastern League | , | |
| Joe Connor | connor002jos | 1904 | 118 g. | Springfield Ponies | Connecticut State League | , | |
| John Connor | connor001joh | 1904 | Kingston Colonials | Hudson River League | , | ||
| O. G. Connor | 1904 | Dayton Veterans | Central League | , | |||
| Thomas Connor | 1904 | 4/26- | Umpire | South Atlantic League | , | ||
| Thomas Connor | 1904 | Umpire | Tri-State League | , | |||
| Connors | connor002joh | 1904 | 4/29-7/17 | South Bend Greens | Central League | , | |
| Connors | connor002joh | 1904 | 7/24-9/12 | Grand Rapids Orphans | Central League | , | |
| Connors | connor022--- | 1904 | 5/16-5/17+ | Columbia | Tennessee-Alabama League | , | |
| Bill Connors | connor001wil | 1904 | 115 g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| Bill Connors | connor002wil | 1904 | 4/30-9/17 | Lowell Tigers | New England League | , | |
| Ed Connors | connor002edw | 1904 | 61 g. | Springfield Ponies | Connecticut State League | , | |
| James Connors | connor002jam | 1904 | 4/28-5/17 | Dayton Veterans | Central League | , | |
| Harlan Conover | conove001har | 1904 | Springfield Hustlers | Illinois-Indiana-Iowa League | , | ||
| John Conrad | conrad002joh | 1904 | 14 g. | Galveston Sand Crabs | South Texas League | , | |
| John Conrad | conrad002joh | 1904 | San Antonio Bronchos | South Texas League | , | ||
| Joe Conroy | conroy000joe | 1904 | Wilkes-Barre PA | Semi-professional | , | ||
| Joe Conroy | conroy000joe | 1904 | 6/7 | Des Moines Prohibitionists | Western League | , | |
| Joe Conroy | conroy000joe | 1904 | 21 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| John Conroy | 1904 | Umpire | Connecticut State League | , | |||
| Pat Conroy | conroy001pat | 1904 | 4/30-7/16 | New Bedford Whalers | New England League | , | |
| Leroy Converse | conver001ler | 1904 | 5/21-5/30 | Winnipeg Maroons | Northern League | , | |
| Leroy Converse | conver001ler | 1904 | 6/23-7/9 | Ottumwa Standpatters | Iowa League | , | |
| David Convey | convey001dav | 1904 | 4/28-5/20 | Evansville River Rats | Central League | , | |
| Robert Conway | 1904 | 8/30-9/6 | Evansville River Rats | Central League | , | ||
| Dan Coogan | coogan003dan | 1904 | U. Pennsylvania | College | , | ||
| Dan Coogan | coogan003dan | 1904 | West Chester-Brandywines | Independent | , | ||
| George Cook | 1904 | Topeka Saints | Missouri Valley League | , | |||
| Herbert Cook | cook--043--- | 1904 | 5/8-9/4 | Olympia Senators | Southwest Washington League | , | |
| Jim Cook | cook--002jam | 1904 | 4/27 | Salt Lake City Elders | Pacific National League | , | |
| Jim Cook | cook--002jam | 1904 | 4/29-5/19 | Boise Fruit Pickers | Pacific National League | , | |
| Jim Cook | cook--002jam | 1904 | 6/3-6/26 | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Manny Cook | 1904 | Hattiesburg | Delta League | , | |||
| Paul Cook | cook--001pau | 1904 | 31 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| Warren Cook | 1904 | KS State Normal | College | , | |||
| Warren Cook | 1904 | Herington | Central Kansas State League | , | |||
| Cooke | cook--052--- | 1904 | +5/24-8/18 | Columbia | Tennessee-Alabama League | , | |
| Cab Cooke | cook--002c-- | 1904 | Columbia | Tennessee-Alabama League | , | ||
| Cab Cooke | cook--002c-- | 1904 | Macon Highlanders | South Atlantic League | , | ||
| Duff Cooley | cooley001duf | 1904 | 122 g. | Boston | National League | Boston, MA | |
| Mel Cooley | cooley001mel | 1904 | +9/24-9/27+ | Enid Evangelists | Southwestern League | , | |
| William Cooley | cooley001wil | 1904 | 4/28-5/29 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| William Cooley | cooley001wil | 1904 | 5/30-6/20 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| William Cooley | cooley001wil | 1904 | 7/31-9/9 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| William Cooley | cooley001wil | 1904 | 7/31-9/9 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| George Coombs | 1904 | preseason | Houston Wanderers | South Texas League | , | ||
| Cooney | cooney014--- | 1904 | 7/2 | New Bedford Whalers | New England League | , | |
| Edward? Cooney | cooney017--- | 1904 | 8/20-8/29 | Rochester Bronchos | Eastern League | , | |
| James Cooney | 1904 | Princeton Univ | College | , | |||
| Phil Cooney | cooney001phi | 1904 | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | ||
| Phil Cooney | cooney001phi | 1904 | Paterson Intruders | Hudson River League | , | ||
| Perry Coons | coons-001per | 1904 | 4/25-6/4 | Colorado Springs Millionaires | Western League | , | |
| Perry Coons | coons-001per | 1904 | 6/13-7/10 | Evansville River Rats | Central League | , | |
| Cooper | cooper045--- | 1904 | Hudson River League | , | |||
| Frank Cooper | cooper001ike | 1904 | Sedalia Goldbugs | Missouri Valley League | , | ||
| George Cooper | cooper004geo | 1904 | Lodi | California State League | , | ||
| George Cooper | cooper004geo | 1904 | Oakland | California State League | , | ||
| George Cooper | cooper004geo | 1904 | Oakland Oaks | Pacific Coast League | , | ||
| Henry Cooper | cooper001hen | 1904 | Charleston WV | Independent | , | ||
| Jimmy Cooper | cooper002jam | 1904 | +7/8+ | Zanesville OH | ProtAssn | , | |
| T. Cope | cope--000t-- | 1904 | 4/30-5/12 | Manchester | New England League | , | |
| Tommy Cope | cope--001tho | 1904 | 94 g. | Pittsburg Coal Diggers | Missouri Valley League | , | |
| Copeland | 1904 | 8/25 | Evansville River Rats | Central League | , | ||
| Tommy Copeland | copela001tho | 1904 | Savannah Pathfinders | South Atlantic League | , | ||
| Tommy Copeland | copela001tho | 1904 | 65 g. | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | |
| Jack Corbett | corbet001jac | 1904 | Wausau WI | Independent | , | ||
| Joe Corbett | corbet001jos | 1904 | -7/29 | 14 g. | St. Louis | National League | St. Louis, MO |
| Joe Corbett | corbet001jos | 1904 | 30 g. | Los Angeles Angels | Pacific Coast League | , | |
| John Corbett | corbet001joh | 1904 | 5/7-8/4+ | Burlington River Rats | Iowa League | , | |
| John Corbett | corbet001joh | 1904 | +8/28-9/5 | Oskaloosa Quakers | Iowa League | , | |
| Ted Corbett | corbet001the | 1904 | 4/22-9/19 | St. Paul Saints | American Association | , | |
| Edward Corbin | corbin000edd | 1904 | MT School Mines | College | , | ||
| Corcoran | corcor004--- | 1904 | 4/27-6/24 | Dallas Giants | Texas League | , | |
| Corcoran | corcor007--- | 1904 | 26 g. | San Antonio Bronchos | South Texas League | , | |
| Phil Corcoran | corcor001phi | 1904 | 38 g. | New Haven Blues | Connecticut State League | , | |
| Frank Cordes | 1904 | 4/29 | Fort Wayne Railroaders | Central League | , | ||
| Robert Corkill | corkil001rob | 1904 | 23 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Robert Corkill | corkil001rob | 1904 | Rock Island Islanders | Illinois-Indiana-Iowa League | , | ||
| Harry Cornen | cornen001har | 1904 | 2 g. | Bridgeport Orators | Connecticut State League | , | |
| Harry Corns | corns-002har | 1904 | 5/7-9/5 | Boone Coal Miners | Iowa League | , | |
| Corr | conn--000gra | 1904 | 19 g. | Topeka Saints | Missouri Valley League | , | |
| Frank Corridon | corrid001fra | 1904 | 19 g. | Chicago | National League | Chicago, IL | |
| Frank Corridon | corrid001fra | 1904 | 12 g. | Philadelphia | National League | Philadelphia, PA | |
| Francis Corrigan | corrig001f-- | 1904 | , | ||||
| Jack Corrigan | corrig002joh | 1904 | 5/19- | 65 g. | Duluth White Sox | Northern League | , |
| Thomas Cosgrove | cosgro001tho | 1904 | 5/1-5/7 | Montreal Royals | Eastern League | , | |
| Cosky | cosky-001--- | 1904 | 1 g. | Columbia | Tennessee-Alabama League | , | |
| Costello | costel028--- | 1904 | 8/11-8/18 | Addison White Sox | Southern Tier League | , | |
| Henry Cote | cote--002hen | 1904 | 4/30-9/17 | Manchester | New England League | , | |
| John Cotter | cotter001joh | 1904 | +7/7-8/8+ | Towanda PA | Independent | , | |
| John Cotter | cotter001joh | 1904 | 9/9 | Elmira | Southern Tier League | , | |
| William Cotter | 1904 | +7/11-8/5+ | Umpire | New York State League | , | ||
| William Cotter | 1904 | +8/24+ | Umpire | Northern New York League | , | ||
| Cottingham | cottin001--- | 1904 | 5/21-7/3 | Chattanooga | Tennessee-Alabama League | , | |
| Cottingham | cottin001--- | 1904 | +7/8-7/26+ | Dalton GA | Independent | , | |
| Cotton | cotton007--- | 1904 | Iowa State Univ. | College | , | ||
| Cotton | cotton007--- | 1904 | 6/3 | Ames IA | Independent | , | |
| Cotton | cotton007--- | 1904 | 6/15-6/17 | Oskaloosa Quakers | Iowa League | , | |
| Bill Coughlin | coughl001wil | 1904-08 | Detroit | American League | Detroit, MI | ||
| Dan Coughlin | coughl002dan | 1904 | +7/23+ | Bristol CT | Independent | , | |
| Jerry Coughlin | 1904 | Roch.-Naveys | Rochester Indoor League | , | |||
| John Coughlin | coughl001joh | 1904 | 4/22-5/4 | Toledo Mud Hens | American Association | , | |
| John Coughlin | coughl001joh | 1904 | 5/14- | Nashua | New England League | , | |
| John Coughlin | coughl001joh | 1904 | -7/21 | Haverhill Hustlers | New England League | , | |
| John Coughlin | coughl001joh | 1904 | 10 g. | Holyoke Paperweights | Connecticut State League | , | |
| William Coughlin | coughl002wil | 1904 | no g. | Montreal Royals | Eastern League | , | |
| William Coughlin | coughl002wil | 1904 | 4/30-5/18 | Nashua | New England League | , | |
| Cy Coulter | coulte001art | 1904 | 4/20-9/20 | Minneapolis Millers | American Association | , | |
| Joe Courneen | courne001jos | 1904 | 5/2-9/10 | Fall River Indians | New England League | , | |
| J.E. Coursey | course000je- | 1904 | 6/29-8/10 | Penn Yan Grape Pickers | Southern Tier League | , | |
| J.E. Coursey | course000je- | 1904 | 8/12-8/19 | Hornellsville Maple Cities | Southern Tier League | , | |
| Ernie Courtney | courtn001edw | 1904 | 4/30-9/28 | Buffalo Bisons | Eastern League | , | |
| Jack Coveney | covene001joh | 1904 | 4/30- | Lawrence Colts | New England League | , | |
| Jack Coveney | covene001joh | 1904 | -9/17 | New Bedford Whalers | New England League | , | |
| George Cowan | cowan-001geo | 1904 | Newark Sailors | Eastern League | , | ||
| Cox | cox---004--- | 1904 | Natchez Indians | Cotton States League | , | ||
| Cox | 1904 | Jackson Senators | Delta League | , | |||
| Chesty Cox | cox---002eug | 1904 | 10 g. | Duluth White Sox | Northern League | , | |
| James Cox | cox---001jam | 1904 | Bowdoin College | College | , | ||
| Jim Cox | 1904 | Wheeling Stogies | Central League | , | |||
| Joseph Cox | cox---001jos | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| Coy | 1904 | 9 g. | Findlay OH | Independent | , | ||
| James Coykendall | 1904 | 5/4-5/25 | Corsicana Oil Citys | Texas League | , | ||
| Frank Coyle | coyle-001fra | 1904 | 4/27-7/21 | Corsicana Oil Citys | Texas League | , | |
| Frank Coyle | coyle-001fra | 1904 | 30 g. | Beaumont Millionaires | South Texas League | , | |
| Frank Coyle | coyle-001fra | 1904 | Umpire | South Texas League | , | ||
| Leech Cracraft | cracra000lee | 1904 | +4/9+ | U. of Virginia | College | , | |
| Edward Craig | craig-001edw | 1904 | Denver Grizzlies | Western League | , | ||
| Edward Craig | craig-001edw | 1904 | 5/7-6/2 | Dallas Giants | Texas League | , | |
| Edward Craig | craig-001edw | 1904 | 44 g. | Springfield Midgets | Missouri Valley League | , | |
| Crane | 1904 | 8/3 | Binghamton Bingoes | New York State League | , | ||
| James Crangle | crangl001jam | 1904 | Springfield Hustlers | Illinois-Indiana-Iowa League | , | ||
| James Crangle | crangl001jam | 1904 | 18+ g. | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | |
| James Crangle | crangl001jam | 1904 | Cairo Champions | Kentucky-Illinois-Tennessee League | , | ||
| Cranston | cranst000--- | 1904 | 8/2- | Wellsville Oil Drillers | Southern Tier League | , | |
| Gavvy Cravath | cravat001cli | 1904 | Los Angeles Angels | Pacific Coast League | , | ||
| Birdie Cree | cree--001wil | 1904 | Washington | Ohio Pennsylvania League | , | ||
| Creech | creech002--- | 1904 | 6/6-8/16 | Burlington River Rats | Iowa League | , | |
| Creech | creech002--- | 1904 | +8/31-9/3 | Oskaloosa Quakers | Iowa League | , | |
| Harold Cribbins | cribbi001har | 1904 | preseason | Atlanta Crackers | Southern Association | , | |
| Harold Cribbins | cribbi001har | 1904 | 5/17 | Knoxville | Tennessee-Alabama League | , | |
| Pat Crisham | crisha002pat | 1904 | 5/6-9/17 | Syracuse Stars | New York State League | , | |
| Pat Crisham | crisha002pat | 1904 | 9/28 | Altoona Mountaineers | Tri-State League | , | |
| Harry Criss | 1904 | Umpire | Northern League | , | |||
| Charles Crist | crist-000cha | 1904 | Helena MT | Independent | , | ||
| Bill Cristall | crista001wil | 1904 | 4/21-7/9 | Toledo Mud Hens | American Association | , | |
| Bill Cristall | crista001wil | 1904 | +7/14-8/24+ | Burlington | Northern New York League | , | |
| Sam Criswell | criswe001sam | 1904 | +5/19+ | 5 g. | Sheffield | Tennessee-Alabama League | , |
| Crocket | 1904 | Newburgh Taylor-mades | Hudson River League | , | |||
| Davey Crockett | crocke001dan | 1904 | 121 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Fred Crolius | croliu001fre | 1904 | 114 g. | Norwich Reds | Connecticut State League | , | |
| Fred Crolius | croliu001fre | 1904 | Coatesville PA | Independent | , | ||
| George Croll | croll-001geo | 1904 | Oakland | California State League | , | ||
| Lyle Cromley | cromle001lyl | 1904 | Georgetown Univ | College | , | ||
| Lyle Cromley | cromle001lyl | 1904 | 5/14-9/20 | Indianapolis Indians | American Association | , | |
| Jack Cronin | cronin001joh | 1904 | - 10/3 | 40 g. | Brooklyn | National League | Brooklyn, NY |
| Tom Crooke | crooke001tho | 1904 | 82 g. | Springfield Ponies | Connecticut State League | , | |
| Cross | cross-021--- | 1904 | 5/5 | Providence Grays | Eastern League | , | |
| Cross | 1904 | 7/13-7/14 | Wheeling Stogies | Central League | , | ||
| A. C. Cross | cross-001a-- | 1904 | 62 g. | Hartford Senators | Connecticut State League | , | |
| Frank Cross | cross-001fra | 1904 | 4/28-8/24 | Evansville River Rats | Central League | , | |
| James Cross | cross-001jam | 1904 | 5/26- | Concord Marines | New England League | , | |
| James Cross | cross-001jam | 1904 | Fall River Indians | New England League | , | ||
| James Cross | cross-001jam | 1904 | -9/16 | Haverhill Hustlers | New England League | , | |
| Lave Cross | cross-001laf | 1904 | 155 g. | Philadelphia | American League | Philadelphia, PA | |
| Lem Cross | cross-001lem | 1904 | 4/30-9/17 | Lowell Tigers | New England League | , | |
| W. C. Cross | 1904 | Joplin Miners | Missouri Valley League | , | |||
| Dan Crotty | crotty001dan | 1904 | +5/22-7/2+ | Umpire | Southwestern League | , | |
| Dan Crotty | crotty001dan | 1904 | 7/24-8/15 | Umpire | Texas League | , | |
| Dan Crotty | crotty001dan | 1904 | +8/24-9/5 | Umpire | Southwestern League | , | |
| Francis Crotty | crotty000fra | 1904 | +5/27-6/28+ | Cairo Champions | Kentucky-Illinois-Tennessee League | , | |
| Francis Crotty | crotty000fra | 1904 | +8/30+ | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| Leo Croughn | crough001--- | 1904 | 8/9-8/16+ | Hornellsville Maple Cities | Southern Tier League | , | |
| Edward Crowder | crowde001ned | 1904 | +7/24+ | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | |
| Charles Crowe | crowe-001cha | 1904 | Niles OH | Independent | , | ||
| Billy Crowell | crowel001bil | 1904 | Umpire | South Texas League | , | ||
| Billy Crowell | crowel001bil | 1904 | Umpire | Texas League | , | ||
| Croze | croze-000--- | 1904 | Calumet Aristocrats | Copper Country League | , | ||
| Crozier | 1904 | 6/23 | Binghamton Bingoes | New York State League | , | ||
| Dick Crozier | crozie001j-- | 1904 | 4/21-9/24 | Atlanta Crackers | Southern Association | , | |
| Charles Crum | crum--001cha | 1904 | 125 g. | Joplin Miners | Missouri Valley League | , | |
| Walter Crum | crum--001wal | 1904 | no g. | Dayton Veterans | Central League | , | |
| Walter Crum | crum--001wal | 1904 | +7/25+ | 43 g. | Sharon PA | Independent | , |
| Otto Crump | crump-004--- | 1904 | +8/15-8/20 | Chattanooga | Tennessee-Alabama League | , | |
| Richard Crutcher | 1904 | Southwestern League | , | ||||
| Joseph Cuddy | cuddy-001joh | 1904 | 421 ab | Saugerties | Hudson River League | , | |
| Joseph Cuddy | cuddy-001joh | 1904 | Saugerties | Hudson River League | , | ||
| Cummings | 1904 | 8/24- | Camden NJ | Independent | , | ||
| Cy Cummings | cummin012--- | 1904 | Wheaton MD | Independent | , | ||
| Bert Cunningham | cunnin001ell | 1904 | 5/6-9/17 | Umpire | New York State League | , | |
| Cupp | cupp--001--- | 1904 | Maryville College | College | , | ||
| Cupp | cupp--001--- | 1904 | +7/12-8/18 | Knoxville | Tennessee-Alabama League | , | |
| George Cuppy | cuppy-001geo | 1904 | Elkhart IN | Independent | , | ||
| Edward Curley | curley000edd | 1904 | 9/12 | Haverhill Hustlers | New England League | , | |
| Walter Curley | curley001doc | 1904 | U. Virginia | College | , | ||
| Walter Curley | curley001doc | 1904 | 6/17-6/19 | Toronto Maple Leafs | Eastern League | , | |
| Walter Curley | curley001doc | 1904 | 7/9-9/25 | Sioux City Soos | Western League | , | |
| Jack Curran | curran001joh | 1904 | 112 g. | Jacksonville Jays | South Atlantic League | , | |
| Clarence Currie | currie001cla | 1904 | 5/3-9/22 | Toronto Maple Leafs | Eastern League | , | |
| Jack Curry | curry-001joh | 1904 | 6/1- | Owosso MI | Independent | , | |
| Jack Curry | curry-001joh | 1904 | 6/13-8/17 | Crookston Crooks | Northern League | , | |
| Jack Curry | curry-001joh | 1904 | Flint-Indep | Independent | , | ||
| Thomas Curtin | curtin001tho | 1904 | Tufts College | College | , | ||
| Thomas Curtin | curtin001tho | 1904 | 7/8-7/29 | Wellsville Oil Drillers | Southern Tier League | , | |
| Thomas Curtin | curtin001tho | 1904 | 8/7-8/12 | Penn Yan Grape Pickers | Southern Tier League | , | |
| Thomas Curtin | curtin001tho | 1904 | 8/5-9/6 | Rochester Bronchos | Eastern League | , | |
| Cliff Curtis | curtis001cli | 1904 | 4/27-9/20 | Milwaukee Brewers | American Association | , | |
| Clyde Curtis | curtis001cly | 1904 | +5/11-9/5 | Ottumwa Standpatters | Iowa League | , | |
| Don Curtis | curtis002don | 1904 | 4/30-5/10 | Wheeling Stogies | Central League | , | |
| Don Curtis | curtis002don | 1904 | 6/12-7/8 | South Bend Greens | Central League | , | |
| Don Curtis | curtis002don | 1904 | 7/10-7/30 | Wheeling Stogies | Central League | , | |
| Gene Curtis | curtis002eug | 1904 | 4/30-7/6 | Wheeling Stogies | Central League | , | |
| Gene Curtis | curtis002eug | 1904 | 7/18 | Wilmington Peaches | Tri-State League | , | |
| Harry Curtis | curtis001har | 1904-05 | Univ. Syracuse | College | , | ||
| Harry Curtis | curtis001har | 1904 | 6/29-9/10 | Elmira | Southern Tier League | , | |
| Joe Curtis | curtis001jos | 1904 | 114 g. | New London Whalers | Connecticut State League | , | |
| Paul Curtis | curtis001pau | 1904 | 38 g. | Sedalia Goldbugs | Missouri Valley League | , | |
| Paul Curtis | curtis001pau | 1904 | 10 g. | Augusta Tourists | South Atlantic League | , | |
| Tom Curtis | curtis001tom | 1904 | 5/28 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Tom Curtis | curtis001tom | 1904 | 5/31-7/30 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Tom Curtis | curtis001tom | 1904 | 7/31-9/9 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Tommy Curvin | curvin000tom | 1904 | 7/8-7/29 | Wellsville Oil Drillers | Southern Tier League | , | |
| Tommy Curvin | curvin000tom | 1904 | 8/7-8/12 | Penn Yan Grape Pickers | Southern Tier League | , | |
| Stephen Cusack | 1904 | 4/24-6/9 | Umpire | Western League | , | ||
| Harvey Cushman | cushma001har | 1904 | 4/24-8/17 | Des Moines Prohibitionists | Western League | , | |
| Harvey Cushman | cushma001har | 1904 | 9/2-9/10+ | Williamsport Millionaires | Tri-State League | , | |
| Win Cutter | cutter002win | 1904 | San Jose | California State League | , | ||
| Win Cutter | cutter002win | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| William Dahlquist | dahlqu001wil | 1904 | 5/20-6/14 | Winnipeg Maroons | Northern League | , | |
| William Dahlquist | dahlqu001wil | 1904 | 7/18-8/1 | Ottumwa Standpatters | Iowa League | , | |
| William Dahlquist | dahlqu001wil | 1904 | +8/24-9/11 | 17 g. | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , |
| William Dahlquist | dahlqu001wil | 1904 | +9/13+ | Williamsburg IA | Independent | , | |
| Con Daily | daily-001con | 1904 | Hudson River League | , | |||
| Daley | 1904 | 5/6-5/10 | Binghamton Bingoes | New York State League | , | ||
| Eddie Daley | daley-001edw | 1904 | 5/6-7/2 | Syracuse Stars | New York State League | , | |
| James Daley | daley-002jam | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| James Daley | daley-002jam | 1904 | 88 g. | Columbia Skyscrapers | South Atlantic League | , | |
| Joe Daley | 1904 | Fall River Indians | New England League | , | |||
| Joe Daley | 1904 | Kingston Colonials | Hudson River League | , | |||
| George Dalrymple | dalrym001geo | 1904 | 52 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| George Dalrymple | dalrym001geo | 1904 | +7/19-8/28+ | Oskaloosa Quakers | Iowa League | , | |
| Bert Daly | daly--001alb | 1904 | Hartford Senators | Connecticut State League | , | ||
| Joseph Daly | daly--000jos | 1904 | 5/10 | Fall River Indians | New England League | , | |
| Tom Daly | daly--002tho | 1904 | 4/30-9/28 | Providence Grays | Eastern League | , | |
| Bill Dammann | damman001bil | 1904 | 46 g. | Spokane Indians | Pacific National League | , | |
| Daniels | daniel019--- | 1904 | 16 g. | Jackson Senators | Delta League | , | |
| Daniels | 1904 | +6/27-6/29+ | Columbia Skyscrapers | South Atlantic League | , | ||
| Daniels | daniel022--- | 1904 | Coatesville | Pennsylvania League | , | ||
| Harry Dannehower | danneh001j-- | 1904 | 4/26-9/9 | Little Rock Travelers | Southern Association | , | |
| Walter Dashwood | dashwo001wal | 1904 | , | ||||
| Augustus Daum | daum--001aug | 1904 | 4/30-9/16 | Nashua | New England League | , | |
| James Davey | davey-002jam | 1904 | Troy-GodsonAC | Amateur | , | ||
| James Davey | davey-002jam | 1904 | 5/9-24, 6/20, | Troy Trojans | New York State League | , | |
| James Davey | davey-002jam | 1904 | 7/3, 7/25 | Troy Trojans | New York State League | , | |
| Robert Davidson | davids001pau | 1904 | 109 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| Davie | davie-002--- | 1904 | 4/24-4/25 | Sioux City Soos | Western League | , | |
| Davies | 1904 | Homestead PA | Independent | , | |||
| Dan Davies | davies001dan | 1904 | 46 g. | Hattiesburg | Delta League | , | |
| W. J. Davies | 1904 | , | |||||
| Davis | davis-001ben | 1904 | 30 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Ben Davis | davis-001ben | 1904 | 122 g. | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |
| Daniel Davis | davis-002dan | 1904 | 9 g. | Newark OH | Independent | , | |
| Elmer Davis | davis-002elm | 1904 | 5/11-8/13+ | Altoona Mountaineers | Tri-State League | , | |
| Elmer Davis | davis-002elm | 1904 | Birmingham Barons | Southern Association | , | ||
| Elmer? Davis | davis-149--- | 1904 | 8/20-8/22 | Rochester Bronchos | Eastern League | , | |
| George Davis | davis-015geo | 1904-09 | Chicago | American League | Chicago, IL | ||
| Gerald Davis | davis-004ger | 1904 | 94 g. | Sedalia Goldbugs | Missouri Valley League | , | |
| Ira Davis | davis-008j-- | 1904 | Portland Browns | Pacific Coast League | , | ||
| Ira Davis | davis-008j-- | 1904 | 12 g. | Butte or Spok | Pacific National League | , | |
| John Davis | 1904 | Penn Yan NY | Independent | , | |||
| Lefty Davis | davis-001alf | 1904 | 5/1-9/20 | Columbus Senators | American Association | , | |
| Paul Davis | davis-002pau | 1904 | 45 g. | New London Whalers | Connecticut State League | , | |
| Si Davis | davis-000si- | 1904 | 4/29-7/4 | Salem Raglands | Oregon State League | , | |
| William Davis | davis-030wil | 1904 | 5/17-10/1 | Harrisburg Senators | Tri-State League | , | |
| Nicholas Daviscourt | davisc000nic | 1904 | 8/7-8/28 | Olympia Senators | Southwest Washington League | , | |
| Lee Dawkins | dawkin001lev | 1904 | 325 ab | Pine Bluff Lumbermen | Cotton States League | , | |
| Fred Dawson | 1904 | 5 g. | Niles OH | Independent | , | ||
| Bill Day | day---001bil | 1904 | 5/3- | New Bedford Whalers | New England League | , | |
| Bill Day | day---001bil | 1904 | Lowell Tigers | New England League | , | ||
| Bill Day | day---001bil | 1904 | -9/15 | Fall River Indians | New England League | , | |
| Henry Daye | daye--001hen | 1904 | Dallas Giants | Texas League | , | ||
| James De Pree | depree000jim | 1904-05 | U. Michigan | College | , | ||
| Snake Deal | deal--002joh | 1904 | 5/1-9/30 | Harrisburg Senators | Tri-State League | , | |
| Dean | dean--010--- | 1904 | +5/25-6/28+ | Sheffield | Tennessee-Alabama League | , | |
| Beach Dean | dean--001bea | 1904 | Oakland | California State League | , | ||
| Homer Dean | dean--000hom | 1904 | Fairhaven HS | High School | , | ||
| Homer Dean | dean--000hom | 1904 | +5/18+ | Bellingham WA | Independent | , | |
| Charlie DeArmond | dearmo002cha | 1904 | 6 g. | Findlay OH | Independent | , | |
| Charlie DeArmond | dearmo002cha | 1904 | Umpire | Central League | , | ||
| Walter Deaver | deaver001wal | 1904 | 4/22-6/13 | Montgomery Senators | Southern Association | , | |
| Walter Deaver | deaver001wal | 1904 | Pine Bluff Lumbermen | Cotton States League | , | ||
| Archie DeBaker | debake001art | 1904 | +5/22+ | Muskegon MI | Independent | , | |
| Decker | 1904 | 7/11 | Grand Rapids Orphans | Central League | , | ||
| Albert Decker | decker001alb | 1904 | 4/28-9/5 | Terre Haute Hottentots | Central League | , | |
| Alonzo DeCosta | decost001a-- | 1904 | Clarksdale | Delta League | , | ||
| John Deering | deerin001joh | 1904 | 4/24-8/16 | Toledo Mud Hens | American Association | , | |
| John Deering | deerin001joh | 1904 | New Haven Blues | Connecticut State League | , | ||
| Rube DeGroff | degrof001edw | 1904 | 4/29-9/28 | Rochester Bronchos | Eastern League | , | |
| Otto Deininger | deinin001ott | 1904 | 4/20-7/8 | Toledo Mud Hens | American Association | , | |
| Henry Deisel | deisel001c-- | 1904 | +6/9-7/16 | Fargo | Northern League | , | |
| Jacob Deisel | deisel001jac | 1904 | Charleston Sea Gulls | South Atlantic League | , | ||
| Charles Deiters | deiter001cha | 1904 | 4/30-9/12 | Wheeling Stogies | Central League | , | |
| Leroy Dekin | dekin-001ler | 1904 | 8/11-8/15 | Utica Pent-Ups | New York State League | , | |
| Frank Delahanty | delaha001fra | 1904 | 4/21-9/23 | Montgomery Senators | Southern Association | , | |
| Jim Delahanty | delaha001jam | 1904 | 142 g. | Boston | National League | Boston, MA | |
| Joe Delahanty | delaha001jos | 1904 | 4/30-9/28 | Buffalo Bisons | Eastern League | , | |
| Tom Delahanty | delaha001tho | 1904 | 205 g. | Seattle Siwashes | Pacific Coast League | , | |
| William Delahanty | deleha001wil | 1904 | no g. | Haverhill Hustlers | New England League | , | |
| William Delahanty | deleha001wil | 1904 | Homestead PA | Independent | , | ||
| William Delahanty | deleha001wil | 1904 | 6/29-8/12 | Penn Yan Grape Pickers | Southern Tier League | , | |
| William Delahanty | deleha001wil | 1904 | 8/16-8/19 | Hornellsville Maple Cities | Southern Tier League | , | |
| Bill Delaney | delane001bil | 1904 | Canton OH | Independent | , | ||
| Charles Delaney | delane014--- | 1904 | 9/4 | Boise Fruit Pickers | Pacific National League | , | |
| William Dell | dell--001wil | 1904 | +7/3+ | Butte MT | Independent | , | |
| Phil Deller | deller001phi | 1904 | 5/6-6/13+ | Boone Coal Miners | Iowa League | , | |
| Phil Deller | deller001phi | 1904 | 11 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Phil Deller | deller001phi | 1904 | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | ||
| Del Delmas | delmas001ber | 1904 | 18 g. | Tacoma Tigers | Pacific Coast League | , | |
| Del Delmas | delmas001ber | 1904 | Seattle Siwashes | Pacific Coast League | , | ||
| Del Delmas | delmas001ber | 1904 | 130 g. | Salt Lake City Elders | Pacific National League | , | |
| Charles Demong | demong001cha | 1904 | +5/13+ | Oneonta NY | Independent | , | |
| Charles Demong | demong001cha | 1904 | 6/30-8/19 | Wellsville Oil Drillers | Southern Tier League | , | |
| Gene DeMontreville | demont001eug | 1904 | St. Louis | American League | St. Louis, MO | ||
| Gene DeMontreville | demont001eug | 1904 | 5/6-9/21 | Atlanta Crackers | Southern Association | , | |
| Lee DeMontreville | demont002leo | 1904 | 4/20-4/26 | Minneapolis Millers | American Association | , | |
| Lee DeMontreville | demont002leo | 1904 | 5/2-5/20 | Indianapolis Indians | American Association | , | |
| Lee DeMontreville | demont002leo | 1904 | 56 g. | Fargo | Northern League | , | |
| Lee DeMontreville | demont002leo | 1904 | 8/15- | Corning White Ponies | Southern Tier League | , | |
| Charles DeMoss | demoss001cha | 1904 | 4/30 | Haverhill Hustlers | New England League | , | |
| St. Julian Dendy | 1904 | Mt | , | ||||
| Ernest Denning | dennin000ern | 1904 | 17 g. | Kent OH | Independent | , | |
| Joseph Denning | 1904 | 9 g. | Kent OH | Independent | , | ||
| Bert Dennis | dennis002ber | 1904 | 4/28-9/11 | Fort Wayne Railroaders | Central League | , | |
| James Denton | denton010--- | 1904 | +4/22+ | U. of Tennessee | College | , | |
| James Denton | denton010--- | 1904 | 5/25 | Knoxville | Tennessee-Alabama League | , | |
| James Denton | denton010--- | 1904 | 7/7 | Chattanooga | Tennessee-Alabama League | , | |
| Owen Depew | depew-001o-- | 1904 | 5/7-9/5 | Boone Coal Miners | Iowa League | , | |
| A. H. Depray | 1904 | Umpire | Pacific Coast League | , | |||
| William Derby | derby-001--- | 1904 | 5/2- | Lawrence Colts | New England League | , | |
| William Derby | derby-001--- | 1904 | Lowell Tigers | New England League | , | ||
| William Derby | derby-001--- | 1904 | -6/18 | Nashua | New England League | , | |
| William Derby | derby-001--- | 1904 | 8/24 | Providence Grays | Eastern League | , | |
| Floyd Derham | derham001f-- | 1904 | Sault Ste. Marie | Northern Copper League | , | ||
| Bert DeRoehn | deroeh001alb | 1904 | 5/4- | Fall River Indians | New England League | , | |
| Bert DeRoehn | deroeh001alb | 1904 | Haverhill Hustlers | New England League | , | ||
| Bert DeRoehn | deroeh001alb | 1904 | -9/17 | Nashua | New England League | , | |
| George Derrick | 1904 | 4/30-6/26 | Umpire | Oregon State League | , | ||
| Billy Derwin | derwin001wil | 1904 | Johnstown Johnnies | Pennsylvania League | , | ||
| Billy Derwin | derwin001wil | 1904 | 8/11-8/26 | Harrisburg Senators | Tri-State League | , | |
| Nick Deshon | denton010--- | 1904 | Stiles Prep | High School | , | ||
| Nick Deshon | denton010--- | 1904-06 | +5/30-6/2+ | Cornell Univ | College | , | |
| Nick Deshon | denton010--- | 1904 | 6/29-8/19 | Wellsville | Independent | , | |
| Sam Deskin | deskin001sam | 1904 | 4/27-8/2 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Sam Deskin | deskin001sam | 1904 | 8/5-8/15 | Corsicana Oil Citys | Texas League | , | |
| John Desmond | desmon000jac | 1904 | Trolley League | , | |||
| Rube Dessau | dessau001fra | 1904 | Elwood OH | Independent | , | ||
| Rube Dessau | dessau001fra | 1904 | 8/1- | 16 g. | Akron OH | Independent | , |
| Devanney | devane001--- | 1904 | 5/16-7/8 | Anniston | Tennessee-Alabama League | , | |
| Devanney | devane001--- | 1904 | +7/15-8/20 | Huntsville | Tennessee-Alabama League | , | |
| Charles Deveaux | 1904 | +6/8+ | 19 g. | Findlay OH | Independent | , | |
| William Devereaux | devere001wil | 1904 | Oakland Oaks | Pacific Coast League | , | ||
| Thomas Devine | devine001tho | 1904 | 8/17-9/17 | Concord Marines | New England League | , | |
| Art Devlin | devlin001art | 1904-11 | New York | National League | New York, NY | ||
| James Dewey | dewey-001jam | 1904 | Lodi | California State League | , | ||
| James Dewey | dewey-001jam | 1904 | Stockton | California State League | , | ||
| Charles Dexter | dexter001cha | 1904 | 4/29-7/6 | Dallas Giants | Texas League | , | |
| Charles Dexter | dexter001cha | 1904 | 7/11-9/10 | Columbia Skyscrapers | South Atlantic League | , | |
| Charlie Dexter | dexter002cha | 1904 | 4/20-9/18 | Louisville Colonels | American Association | , | |
| Diaz | 1904 | Hattiesburg | Delta League | , | |||
| Guy Dickey | dickey001guy | 1904 | 4/20-9/18 | Indianapolis Indians | American Association | , | |
| Charles Diebold | 1904 | Johnstown PA | Independent | , | |||
| Charles Diebold | 1904 | 6 g. | Niles OH | Independent | , | ||
| Charles Diebold | 1904 | Pittsburgh AC | Independent | , | |||
| Ernie Diehl | diehl-001ern | 1904 | 12 g. | Pittsburgh | National League | Pittsburgh, PA | |
| Ernie Diehl | diehl-001ern | 1904 | Avondale OH | Independent | , | ||
| Harry Diehl | diehl-001har | 1904 | 4/25-9/25 | St. Joseph Saints | Western League | , | |
| Edward Diestelkamp | diesel001e-- | 1904 | 5/16-6/1+ | Bessemer | Tennessee-Alabama League | , | |
| Edward Diestelkamp | diesel001e-- | 1904 | 34 g. | Chattanooga | Tennessee-Alabama League | , | |
| Edward Diestelkamp | diesel001e-- | 1904 | Sheffield | Tennessee-Alabama League | , | ||
| Edward Diestelkamp | diesel001e-- | 1904 | 43 g. | Fort Scott Giants | Missouri Valley League | , | |
| George Diggins | diggin000geo | 1904 | 6/25 | Concord Marines | New England League | , | |
| William Diggins | diggin001wil | 1904 | 5/20- | Concord Marines | New England League | , | |
| William Diggins | diggin001wil | 1904 | -9/17 | Lowell Tigers | New England League | , | |
| Milton Dillard | dillar001mil | 1904 | 80 g. | Yazoo City Zoos | Delta League | , | |
| Pat Dillard | dillar002pat | 1904 | 4/29-9/28 | Newark Sailors | Eastern League | , | |
| Ed Dillon | dillon001edw | 1904 | 5/20- | Grand Forks Forkers | Northern League | , | |
| Ed Dillon | dillon001edw | 1904 | +6/13 | Winnipeg Maroons | Northern League | , | |
| Ed Dillon | dillon001edw | 1904 | 59 ab | Greenville Cotton Pickers | Cotton States League | , | |
| Ed Dillon | dillon001edw | 1904 | 38 g. | Yazoo City Zoos | Delta League | , | |
| Frank Dillon | dillon001fra | 1904 | 135 g. | Brooklyn | National League | Brooklyn, NY | |
| Jack Dillon | dillon002joh | 1904 | 4/29-7/22 | Jersey City Skeeters | Eastern League | , | |
| Jack Dillon | dillon002joh | 1904 | 9/10 | Jersey City Skeeters | Eastern League | , | |
| Tom Dillon | dillon001tho | 1904 | 4/30-6/1 | Lawrence Colts | New England League | , | |
| Fred Dingle | dingle001fre | 1904 | 112 g. | Jacksonville Jays | South Atlantic League | , | |
| George Disch | disch-001geo | 1904 | St. Edwards Col. | College | , | ||
| George Disch | disch-001geo | 1904 | 5/31-9/5 | Marshalltown Grays | Iowa League | , | |
| William Disch | disch-001wil | 1904 | St. Edwards | College | , | ||
| William Disch | disch-001wil | 1904 | 6/30-8/13 | Fort Worth Panthers | Texas League | , | |
| William Disch | disch-001wil | 1904 | 17 g. | Galveston Sand Crabs | South Texas League | , | |
| William Dithridge | dithri001wil | 1904 | +7/8+ | Zanesville OH | ProtAssn | , | |
| Clyde Dixon | dixon-001cly | 1904 | Umpire | South Texas League | , | ||
| John Dobbins | dobbin001j-- | 1904 | 7/24- | Camden NJ | Independent | , | |
| John Dobbs | dobbs-001joh | 1904 | Brooklyn | National League | Brooklyn, NY | ||
| Dodson | dodson010--- | 1904 | 4 g. | Burlington River Rats | Iowa League | , | |
| Fred Doe | doe---002fre | 1904 | 7/4 | New Bedford Whalers | New England League | , | |
| William Doerr | doerr-001wil | 1904 | Leavenworth Orioles | Missouri Valley League | , | ||
| James Doherty | dohert004jam | 1904 | 5/11-5/17 | Altoona Mountaineers | Tri-State League | , | |
| Mike Doherty | dohert001mic | 1904 | 5/6-9/18 | Albany Senators | New York State League | , | |
| Cozy Dolan | dolan-001pat | 1904 | Cincinnati | National League | Cincinnati, OH | ||
| Joe Dolan | dolan-001jos | 1904 | 4/24-9/25 | Omaha Rangers | Western League | , | |
| John Dolan | dolan-002joh | 1904 | 23 g. | Youngstown OH | Independent | , | |
| John Dolan | dolan-004joh | 1904 | 9/10-9/25 | Wilmington Peaches | Tri-State League | , | |
| Fred Doll | doll--001fre | 1904 | +5/28-6/12 | Superior Longshoremen | Northern League | , | |
| Fred Doll | doll--001fre | 1904 | 6/13 | Duluth White Sox | Northern League | , | |
| Fred Doll | doll--001fre | 1904 | 6/14-7/24+ | Superior Longshoremen | Northern League | , | |
| Fred Doll | doll--001fre | 1904 | 8/24-9/5 | Ottumwa Standpatters | Iowa League | , | |
| Lewis Doll | 1904 | Sheffield | Tennessee-Alabama League | , | |||
| Louis Doll | 1904 | Cairo Champions | Kentucky-Illinois-Tennessee League | , | |||
| Louis Doll | 1904 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |||
| Louis Doll | 1904 | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |||
| Ralph Doll | 1904 | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | |||
| Ralph Doll | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |||
| Ralph Doll | 1904 | 8/20-8/30 | Evansville River Rats | Central League | , | ||
| Dom | dom---000--- | 1904 | 5/8-5/15 | Olympia Senators | Southwest Washington League | , | |
| Dombrosky | 1904 | 3 g. | Findlay OH | Independent | , | ||
| Donahue | 1904 | Columbia College | College | , | |||
| Donahue | 1904 | Newburgh Taylor-mades | Hudson River League | , | |||
| Donahue | donahu017--- | 1904 | 6/21- | Waterloo Microbes | Iowa League | , | |
| C. Donahue | donahu003pat | 1904 | 9/1-9/6 | Utica Pent-Ups | New York State League | , | |
| Dennis Donahue | donahu001den | 1904 | 5/28- | Coudersport PA | Independent | , | |
| Dennis Donahue | donahu001den | 1904 | 8/24-8/30 | Coudersport | Southern Tier League | , | |
| Dennis Donahue | donahu003pat | 1904 | 9/1-9/6 | Utica Pent-Ups | New York State League | , | |
| Jiggs Donahue | donahu001joh | 1904 | Chicago | American League | Chicago, IL | ||
| Pat Donahue | donahu003pat | 1904 | 5/8-9/11 | Utica Pent-Ups | New York State League | , | |
| Red Donahue | donahu001fra | 1904 | Cleveland | American League | Cleveland, OH | ||
| She Donahue | donahu002cha | 1904 | 4/19- | 4 g. | St. Louis | National League | St. Louis, MO |
| She Donahue | donahu002cha | 1904 | - 10/3 | 58 g. | Philadelphia | National League | Philadelphia, PA |
| Thomas Donahue | donahu001tho | 1904 | 17 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Thomas Donahue | donahu001tho | 1904 | 6/17-9/5 | Oskaloosa Quakers | Iowa League | , | |
| Edward Donnelly | donnel001edw | 1904 | 9/3-9/13 | Troy Trojans | New York State League | , | |
| Frank Donnelly | donnel002fra | 1904 | 118 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Frank Donnelly | donnel004fra | 1904 | Kingston Colonials | Hudson River League | , | ||
| John Donnelly | donnel001joh | 1904 | 79 g. | Charleston Sea Gulls | South Atlantic League | , | |
| August Donohoo | 1904 | Talladega AL | , | ||||
| Donovan | donova048--- | 1904 | 6/20- | 4 g. | Nashua | New England League | , |
| Donovan | donova048--- | 1904 | -8/31 | Fall River Indians | New England League | , | |
| Donovan | 1904 | 6/30-7/2 | Wheeling Stogies | Central League | , | ||
| Billy Donovan | donova006--- | 1904 | 5/12-5/15 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Billy Donovan | donova006--- | 1904 | 5/18-7/4 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Dan Donovan | donova050--- | 1904 | Deadwood | , | |||
| Dan Donovan | donova050--- | 1904 | 6/21-6/25 | Sioux City Soos | Western League | , | |
| Fred Donovan | donova002fre | 1904 | 120 g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| James Donovan | donova001jam | 1904 | U. of Tennessee | College | , | ||
| James Donovan | donova001jam | 1904 | +6/27-6/30+ | Chattanooga | Tennessee-Alabama League | , | |
| Jerry Donovan | donova001jer | 1904 | Williamsport Millionaires | Tri-State League | , | ||
| Jerry Donovan | donova003jer | 1904-05 | Tufts University | College | , | ||
| Martin Donovan | donova002mar | 1904 | 5/3-5/5 | Lawrence Colts | New England League | , | |
| Mike Donovan | donova002mic | 1904 | 5/29- | 2 g. | Cleveland | American League | Cleveland, OH |
| Mike Donovan | donova002mic | 1904 | 6/22-8/2 | Toledo Mud Hens | American Association | , | |
| Mike Donovan | donova002mic | 1904 | 8/9-9/24 | Shreveport Pirates | Southern Association | , | |
| Tom Donovan | donova002tho | 1904 | 5/6-9/18 | Albany Senators | New York State League | , | |
| Dooley | 1904 | 4/28-5/17 | Marion Oilworkers/Peoria Distillers | Central League | , | ||
| Dooley | 1904 | 5/25-6/19 | Grand Rapids Orphans | Central League | , | ||
| Mickey Doolin | doolan001mic | 1904 | 4/29-9/28 | Jersey City Skeeters | Eastern League | , | |
| Frank Doran | doran-001fra | 1904 | 53 g. | Hartford Senators | Connecticut State League | , | |
| Tom Doran | doran-002tho | 1904 | 4/29-5/22 | Montreal Royals | Eastern League | , | |
| Tom Doran | doran-002tho | 1904 | 4/19- | 12 g. | Boston | American League | Boston, MA |
| Connie Doremus | doremu001con | 1904 | Greenville Cotton Pickers | Cotton States League | , | ||
| William Dorgan | dorgan001wil | 1904 | 4/30- | Concord Marines | New England League | , | |
| William Dorgan | dorgan001wil | 1904 | -9/17 | Lowell Tigers | New England League | , | |
| Johnny Dorman | dorman001joh | 1904 | Georgetown | College | , | ||
| Johnny Dorman | dorman001joh | 1904 | +7/14-8/24+ | Montpelier-Barre | Northern New York League | , | |
| Peter Dorn | dorn--001pet | 1904 | Birmingham Barons | Southern Association | , | ||
| Peter Dorn | dorn--001pet | 1904 | 4 g. | Findlay OH | Independent | , | |
| Gus Dorner | dorner001aug | 1904 | 4/22-9/20 | Columbus Senators | American Association | , | |
| Hugh Dorrance | 1904 | Kent OH | Independent | , | |||
| Hugh Dorrance | 1904 | +7/4+ | Akron-Barberton | Independent | , | ||
| Joseph Dorsa | dorsey001joe | 1904 | +5/15+ | Dallas-Eagles | Amateur | , | |
| Joseph Dorsa | dorsey001joe | 1904 | 7/4-7/17 | Corsicana Oil Citys | Texas League | , | |
| Joseph Dorsa | dorsey001joe | 1904 | +10/2+ | Dall-K.ofColumbus | Amateur | , | |
| Luke Dorsey | dorsey001luk | 1904 | 5/20-6/3 | New Bedford Whalers | New England League | , | |
| Jack Doscher | dosche001joh | 1904 | 2 g. | Brooklyn | National League | Brooklyn, NY | |
| Jack Doscher | dosche001joh | 1904 | 7/11-9/16 | Troy Trojans | New York State League | , | |
| Doss | 1904 | Newburgh Taylor-mades | Hudson River League | , | |||
| John Doubles | double001j-- | 1904 | 37 g. | Sharon PA | Independent | , | |
| Dougherty | doughe017--- | 1904 | 6/29-8/10 | Penn Yan Grape Pickers | Southern Tier League | , | |
| James Dougherty | doughe001jam | 1904 | Ardmore IT | Independent | , | ||
| James Dougherty | doughe001jam | 1904 | 8/5-8/15 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Patsy Dougherty | doughe002pat | 1904 | 49 g. | Boston | American League | Boston, MA | |
| Patsy Dougherty | doughe002pat | 1904 | 106 g. | New York | American League | New York, NY | |
| Tom Dougherty | doughe001tho | 1904 | 4/24 | Chicago | American League | Chicago, IL | |
| Tom Dougherty | doughe001tho | 1904 | 6/10-9/18 | Milwaukee Brewers | American Association | , | |
| Archibald Douglas | dougla000hug | 1904 | Columbia | Tennessee-Alabama League | , | ||
| Archibald Douglas | dougla000hug | 1904 | USNA | College | , | ||
| Archibald Douglas | dougla000hug | 1904 | Columbia | Tennessee-Alabama League | , | ||
| Archibald Douglas | dougla000hug | 1904 | USNA | College | , | ||
| Klondike Douglass | dougla004wil | 1904 | -4/16 | 3 g. | Philadelphia | National League | Philadelphia, PA |
| Doutelle | 1904 | 13 g. | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | ||
| Doutelle | 1904 | +7/28+ | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | ||
| George Dovey | dovey-001geo | 1904 | 5/3-6/12 | Camden | Tri-State League | , | |
| George Dovey | dovey-001geo | 1904 | Utica Pent-Ups | New York State League | , | ||
| George Dovey | dovey-001geo | 1904 | 14 g. | Jacksonville Jays | South Atlantic League | , | |
| George Dovey | dovey-001geo | 1904 | 7/4-7/11 | Atlantic City NJ | Independent | , | |
| Tommy Dowd | dowd--001tho | 1904 | 4/27-5/29 | New Orleans Pelicans | Southern Association | , | |
| Tommy Dowd | dowd--001tho | 1904 | Holyoke Paperweights | Connecticut State League | , | ||
| Roy Dowers | dowers001roy | 1904 | 5/7-9/5 | Keokuk Indians | Iowa League | , | |
| Joe Dowie | dowie-001joe | 1904 | 4/30-9/2 | Houston Wanderers | South Texas League | , | |
| Patrick Dowling | dowlin001pat | 1904 | Georgetown Col. | College | , | ||
| Patrick Dowling | dowlin001pat | 1904 | 6/1-9/10 | Wilmington Peaches | Tri-State League | , | |
| Pete Dowling | dowlin001hen | 1904 | 29 g. | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Jim Downey | downey002jam | 1904 | 5/11-9/17 | Memphis Egyptians | Southern Association | , | |
| Thomas Downey | downey002tho | 1904 | 4/29-7/4 | Salem Raglands | Oregon State League | , | |
| Thomas Downey | downey002tho | 1904 | 7/10-9/4 | Centralia Midgets | Southwest Washington League | , | |
| Tom Downey | downey003tho | 1904 | 115 g. | Bridgeport Orators | Connecticut State League | , | |
| Downing | downin007--- | 1904 | 4/28-6/26+ | Eugene Blues | Oregon State League | , | |
| Patrick Downing | downin002pat | 1904 | 22 ab | Greenville Cotton Pickers | Cotton States League | , | |
| Patrick Downing | downin002pat | 1904 | -9/4 | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | |
| Red Downs | downs-001jer | 1904 | 4/24-4/25 | Omaha Rangers | Western League | , | |
| Red Downs | downs-001jer | 1904 | 117 g. | Fort Scott Giants | Missouri Valley League | , | |
| Charles Doyle | doyle-002cha | 1904 | Tacoma Tigers | Pacific Coast League | , | ||
| Charles Doyle | doyle-004cha | 1904 | 4/29-5/4 | Montreal Royals | Eastern League | , | |
| F. Doyle | 1904 | 37 g. | Newark OH | Independent | , | ||
| F. Doyle | 1904 | Coshocton OH | Independent | , | |||
| J. Doyle | 1904 | 38 g. | Ashland | Independent | , | ||
| J. Doyle | 1904 | Newark OH | Independent | , | |||
| Jack Doyle | doyle-002joh | 1904 | 8 g. | Brooklyn | National League | Brooklyn, NY | |
| Jack Doyle | doyle-002joh | 1904 | 66 g. | Philadelphia | National League | Philadelphia, PA | |
| Jack Doyle | 1904 | Little Rock Travelers | Southern Association | , | |||
| James Doyle | doyle-001jam | 1904 | San Jose | California State League | , | ||
| Slow Joe Doyle | doyle-001jud | 1904 | Baton Rouge Red Sticks | Cotton States League | , | ||
| Slow Joe Doyle | doyle-001jud | 1904 | 8/4-9/12 | Wheeling Stogies | Central League | , | |
| Thomas Doyle | doyle-005tho | 1904 | 5/13 | Lawrence Colts | New England League | , | |
| William Doyle | doyle-008wil | 1904 | 4/27-8/15 | Dallas Giants | Texas League | , | |
| Delos Drake | drake-002del | 1904 | 16 g. | Findlay OH | Independent | , | |
| Herbert Drake | drake-002har | 1904 | 4/13-5/30+ | Bucknell Univ. | College | , | |
| Herbert Drake | drake-002har | 1904 | 8/30-9/8 | Coudersport | Southern Tier League | , | |
| Jack Drennan | drenna001kir | 1904 | Portland Browns | Pacific Coast League | , | ||
| Mike Drennan | drenna001mik | 1904 | Providence Grays | Eastern League | , | ||
| Mike Drennan | drenna001mik | 1904 | 7/23-8/8 | Lebanon | Tri-State League | , | |
| Mike Drennan | drenna001mik | 1904 | +9/2+ | Umpire | Tri-State League | , | |
| Bob Dresser | dresse001rob | 1904 | Montpelier-Barre | Northern New York League | , | ||
| Dressler | dressl000--- | 1904 | 9 g. | Oskaloosa Quakers | Iowa League | , | |
| Drew | drew--007--- | 1904 | 5/8-5/12+ | Olympia Senators | Southwest Washington League | , | |
| Bobby Drew | drew--001edw | 1904 | 5/11-5/17+ | Altoona Mountaineers | Tri-State League | , | |
| Bobby Drew | drew--001edw | 1904 | New London Whalers | Connecticut State League | , | ||
| Bobby Drew | drew--001edw | 1904 | Norwich Reds | Connecticut State League | , | ||
| Frank Drill | drill-000fra | 1904 | 5/6 | Haverhill Hustlers | New England League | , | |
| Frank Drill | drill-000fra | 1904 | 7/29-8/2 | Colorado Springs Millionaires | Western League | , | |
| Lew Drill | drill-001lew | 1904 | 46 g. | Washington | American League | Washington, DC | |
| Lew Drill | drill-001lew | 1904 | 51 g. | Detroit | American League | Detroit, MI | |
| Vianello Drinkwater | drinkw001via | 1904 | 17 g. | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Vianello Drinkwater | drinkw001via | 1904 | Spokane Indians | Pacific National League | , | ||
| Vianello Drinkwater | drinkw001via | 1904 | Salt Lake City Elders | Pacific National League | , | ||
| Driscoll | drisco012--- | 1904 | 8/9-8/10 | Sioux City Soos | Western League | , | |
| Charles Driscoll | drisco002wil | 1904 | 5/28-7/7 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Charles Driscoll | drisco002wil | 1904 | 7/12-9/17 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Jimmy Driscoll | drisco004jam | 1904 | 7/27-9/17 | Lawrence Colts | New England League | , | |
| James Drohan | drohan001jam | 1904 | Pawt.-Conants | Independent | , | ||
| Carl Druhot | druhot001car | 1904 | 20 g. | Portland Browns | Pacific Coast League | , | |
| Ferd Drumm | drumm-001fer | 1904 | Zanesville OH | ProtAssn | , | ||
| Tom Drummy | drummy001tom | 1904 | +6/8+ | Topeka Saints | Missouri Valley League | , | |
| Bob Drury | drury-001rob | 1904 | 5/7-9/17 | Binghamton Bingoes | New York State League | , | |
| Edward Drury | drury-000edw | 1904 | Greenville Cotton Pickers | Cotton States League | , | ||
| Frank DuChien | duchie001fra | 1904 | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | ||
| Frank DuChien | duchie001fra | 1904 | 5/15- | Oshkosh WI | Independent | , | |
| Frank DuChien | duchie001fra | 1904 | -8/ | Green Bay WI | Independent | , | |
| Duck | 1904 | 9/11 | South Bend Greens | Central League | , | ||
| Duff | 1904 | Brookhaven | Delta League | , | |||
| Pat Duff | duff--001pat | 1904 | +7/14-8/24+ | Rutland | Northern New York League | , | |
| Pat Duff | duff--001pat | 1904 | 9/16-9/28 | Jersey City Skeeters | Eastern League | , | |
| Hugh Duffy | duffy-001hug | 1904-06 | Philadelphia | National League | Philadelphia, PA | ||
| Jim Duffy | duffy-001jam | 1904 | 4/30-6/15 | Lawrence Colts | New England League | , | |
| John Duffy | duffy-003joh | 1904 | 4/21-9/24 | Birmingham Barons | Southern Association | , | |
| Luke Duffy | duffy-001luk | 1904 | no g. | Evansville River Rats | Central League | , | |
| Luke Duffy | duffy-001luk | 1904 | Springfield Hustlers | Illinois-Indiana-Iowa League | , | ||
| Luke Duffy | duffy-001luk | 1904 | 58+ g. | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | |
| Tom Dugan | dugan-001tho | 1904 | 4/27-8/2 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Tom Dugan | dugan-001tho | 1904 | 8/5-9/15 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Dan Dugdale | dugdal001dan | 1904 | Portland Browns | Pacific Coast League | , | ||
| Daniel Duggan | duggan001dan | 1904 | 5/1-5/21 | Providence Grays | Eastern League | , | |
| Daniel Duggan | duggan001dan | 1904 | 6/14- | Nashua | New England League | , | |
| Daniel Duggan | duggan001dan | 1904 | -9/17 | Concord Marines | New England League | , | |
| Clarence Dunbar | dunbar000har | 1904 | no g. | Indianapolis Indians | American Association | , | |
| Fred Dunbar | dunbar000fre | 1904 | 5/2-5/13 | New Bedford Whalers | New England League | , | |
| Gus Dundon | dundon001aug | 1904 | 4/14- | 108 g. | Chicago | American League | Chicago, IL |
| Sam Dungan | dungan001sam | 1904 | 4/23-9/24 | Memphis Egyptians | Southern Association | , | |
| Turk Dunham | 1904 | +9/18+ | Coffeyville KS | Independent | , | ||
| Wiley Dunham | dunham001hen | 1904 | 4/27-7/12 | New Orleans Pelicans | Southern Association | , | |
| Wiley Dunham | dunham001hen | 1904 | 7/18-9/23 | Birmingham Barons | Southern Association | , | |
| Davy Dunkle | dunkle001edw | 1904 | Washington | American League | Washington, DC | ||
| Davy Dunkle | dunkle001edw | 1904 | 8/11-8/30 | Williamsport Millionaires | Tri-State League | , | |
| Ernest Dunlap | dunlap001e-- | 1904 | 5/16-8/20 | Decatur | Tennessee-Alabama League | , | |
| Ernest Dunlap | dunlap001e-- | 1904 | 22 g. | Augusta Tourists | South Atlantic League | , | |
| Ernest Dunlap | dunlap001e-- | 1904 | 9/24 | Memphis Egyptians | Southern Association | , | |
| George Dunlap | dunlap008--- | 1904 | +5/26+ | Coe University | College | , | |
| George Dunlap | dunlap008--- | 1904 | 6/14-8/16 | Ottumwa Standpatters | Iowa League | , | |
| Jack Dunleavy | dunlea001joh | 1904 | 51 g. | St. Louis | National League | St. Louis, MO | |
| Dunn | dunn--037--- | 1904 | Carlisle | Pennsylvania League | , | ||
| Bert Dunn | dunn--005ber | 1904 | 4/27-8/15 | Fort Worth Panthers | Texas League | , | |
| Bert Dunn | dunn--003ber | 1904 | 4/26-5/12 | Sioux City Soos | Western League | , | |
| Bert Dunn | dunn--003ber | 1904 | 5/19-7/24+ | Grand Forks Forkers | Northern League | , | |
| Bert Dunn | dunn--003ber | 1904 | 33 g. | Topeka Saints | Missouri Valley League | , | |
| Jack Dunn | dunn--005joh | 1904 | 64 g. | New York | National League | New York, NY | |
| William Dunn | dunn--001wil | 1904 | 5/7-5/14 | Syracuse Stars | New York State League | , | |
| William Dunn | dunn--001wil | 1904 | 5/20-6/6 | Utica Pent-Ups | New York State League | , | |
| William Dunn | dunn--001wil | 1904 | 8/1-9/10 | Corning White Ponies | Southern Tier League | , | |
| Frank Dunne | dunne-001f-- | 1904 | 52 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Frank Dupee | dupee-001fra | 1904 | New Haven Blues | Connecticut State League | , | ||
| John Duplaine | duplai001joh | 1904 | 57 g. | Jackson Senators | Delta League | , | |
| John Duplaine | duplai001joh | 1904 | 34 g. | Macon Highlanders | South Atlantic League | , | |
| Dupre | dupre-000--- | 1904 | +8/25+ | Easthampton MA | Independent | , | |
| Alexander Dupree | dupree001ale | 1904 | 5/2-9/27+ | Oklahoma City Mets | Southwestern League | , | |
| George Duquette | duquet001geo | 1904 | Rochester Bronchos | Eastern League | , | ||
| George Duquette | duquet001geo | 1904 | Paterson Intruders | Hudson River League | , | ||
| George Duquette | duquet001geo | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| Dan Durand | durand001h-- | 1904 | Pittsburg Coal Diggers | Missouri Valley League | , | ||
| Dan Durand | durand001h-- | 1904 | Sedalia Goldbugs | Missouri Valley League | , | ||
| Dan Durand | durand001h-- | 1904 | Topeka Saints | Missouri Valley League | , | ||
| Blaine Durbin | durbin001bla | 1904 | 33 g. | Fort Scott Giants | Missouri Valley League | , | |
| Durfee | durfee000--- | 1904 | 6/29-7/4 | Addison White Sox | Southern Tier League | , | |
| Durfee | durfee000--- | 1904 | 6/29-7/4 | Addison White Sox | Southern Tier League | , | |
| Durham | durham010--- | 1904 | 8/11-8/18 | Wellsville Oil Drillers | Southern Tier League | , | |
| Bull Durham | durham001lou | 1904 | no g. | Buffalo Bisons | Eastern League | , | |
| Bull Durham | durham001lou | 1904 | 34 g. | Augusta Tourists | South Atlantic League | , | |
| Bull Durham | durham001lou | 1904 | 9/15- | 2 g. | Brooklyn | National League | Brooklyn, NY |
| James Durham | durham003jam | 1904 | 4/20-9/19 | 41 g. | Kansas City Blues | American Association | , |
| Earl Durkee | durkee001ear | 1904 | 122 g. | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |
| Earl Durkee | durkee001ear | 1904 | Rock Island Islanders | Illinois-Indiana-Iowa League | , | ||
| Earl Durkee | durkee001ear | 1904 | Springfield Hustlers | Illinois-Indiana-Iowa League | , | ||
| Robert Durnbaugh | durnba001rob | 1904 | Springfield Ponies | Connecticut State League | , | ||
| Ike Durrett | durret001isa | 1904 | 4/21-9/2 | Montgomery Senators | Southern Association | , | |
| Frank DuShane | dushan001fra | 1904 | 4/28- | Eugene Blues | Oregon State League | , | |
| Charles Dwyer | dwyer-003jam | 1904 | 9/7-9/9 | Atlanta Crackers | Southern Association | , | |
| Charles Dwyer | dwyer-003jam | 1904 | 9/19-9/22 | Little Rock Travelers | Southern Association | , | |
| James Dwyer | dwyer-004jam | 1904 | 9/7-9/9 | Atlanta Crackers | Southern Association | , | |
| James Dwyer | dwyer-004jam | 1904 | 9/19-9/22 | Little Rock Travelers | Southern Association | , | |
| Timothy Dwyer | dwyer-001tim | 1904 | 4/30- | Lowell Tigers | New England League | , | |
| Timothy Dwyer | dwyer-001tim | 1904 | -9/19 | Fall River Indians | New England League | , | |
| Arthur Dye | dye---009--- | 1904 | 5/8-9/4 | Olympia Senators | Southwest Washington League | , | |
| Billy Dyer | dyer--001wil | 1904 | Worcester | , | |||
| Billy Dyer | dyer--001wil | 1904 | 52 g. | Norwich Reds | Connecticut State League | , | |
| Billy Dyer | dyer--001wil | 1904 | 7/12-9/28 | Montreal Royals | Eastern League | , | |
| Jimmy Dygert | dygert001jam | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| Wesley Eads | 1904 | +7/19+ | Shawnee Browns/Chickasha Indians | Southwestern League | , | ||
| William Eads | eads--000wil | 1904 | Fremont NE | Independent | , | ||
| Pete Eagan | eagan-001pat | 1904 | 5/6-9/17 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Truck Eagan | eagan-001cha | 1904 | 200 g. | Tacoma Tigers | Pacific Coast League | , | |
| Bobby Eager | eager-001rob | 1904 | Los Angeles Angels | Pacific Coast League | , | ||
| Howard Earl | earl--002how | 1904 | 5/6-9/17 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Billy Earle | earle-001bil | 1904 | 227 ab | Vicksburg Hill Billies | Cotton States League | , | |
| Carl Easley | easley001--- | 1904 | 5/8-7/3 | Centralia Midgets | Southwest Washington League | , | |
| Mal Eason | eason-001mal | 1904 | 5/1-9/28 | Jersey City Skeeters | Eastern League | , | |
| Walter East | east--002wal | 1904 | 65 g. | Shanon PA | Independent | , | |
| Walter East | east--002wal | 1904 | Akron OH | Independent | , | ||
| Frank Eastley | eastle001fra | 1904 | Pitt.-Collegians | Independent | , | ||
| Frank Eastley | eastle001fra | 1904 | 8/4-8/5 | Altoona Mountaineers | Tri-State League | , | |
| Chris Eastman | eastma001chr | 1904 | 31 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| Chris Eastman | eastma001chr | 1904 | Winona MN | , | |||
| DeWorth Easton | easton001dew | 1904 | 5/7-8/25 | Fort Dodge Gypsum Eaters | Iowa League | , | |
| George Eaton | eaton-001geo | 1904 | 4/30- | Concord Marines | New England League | , | |
| George Eaton | eaton-001geo | 1904 | -9/17 | Lawrence Colts | New England League | , | |
| Hi Ebright | ebrigh001hi- | 1904 | Lincoln | , | |||
| Mills Ebright | ebrigh001a-- | 1904 | Baker Univ. | College | , | ||
| Mills Ebright | ebrigh001a-- | 1904 | 101 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Walter Eckersall | 1904 | Chicago U. | College | , | |||
| Andrew Ecklund | ecklun001and | 1904 | +7/10+ | Bonner MT | Independent | , | |
| Sydney Eckstone | ecksto001sid | 1904 | +6/2-7/2+ | Sheffield | Tennessee-Alabama League | , | |
| Bob Edmondson | edmond002rob | 1904 | 4/30-9/2 | Houston Wanderers | South Texas League | , | |
| Otis Edmondson | edmond001oti | 1904 | 2 g. | Sheffield | Tennessee-Alabama League | , | |
| David Edmunds | edmund002dav | 1904 | no g. | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| David Edmunds | edmund002dav | 1904 | 4/26-5/3+ | Augusta Tourists | South Atlantic League | , | |
| Pearl Edmunds | edmond001pea | 1904 | 36 g. | Hattiesburg | Delta League | , | |
| Pearl Edmunds | edmond001pea | 1904 | 5/16-6/14 | Anniston | Tennessee-Alabama League | , | |
| Mays Edmundson | edmund001may | 1904 | 4/29-5/5 | Montreal Royals | Eastern League | , | |
| Mays Edmundson | edmund001may | 1904 | +9/5+ | Homestead PA | Independent | , | |
| Edwards | 1904 | +4/28+ | Augusta Tourists | South Atlantic League | , | ||
| Edwards | 1904 | 5/10 | Wheeling Stogies | Central League | , | ||
| Edwards | edward048--- | 1904 | 9/7-9/8 | Concord Marines | New England League | , | |
| Edwards | edward060--- | 1904 | Lafayette College | College | , | ||
| Edwards | edward060--- | 1904 | 6/30-9/6 | Corning White Ponies | Southern Tier League | , | |
| Dave Edwards | edward007dav | 1904 | 5/15-9/4 | Olympia Senators | Southwest Washington League | , | |
| Jack Edwards | edward023--- | 1904 | 11 g. | Sedalia Goldbugs | Missouri Valley League | , | |
| Joseph Edwards | edward001gil | 1904 | 24 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| Ralph Edwards | 1904 | Charleston Sea Gulls | South Atlantic League | , | |||
| W. Edwards | edward004w-- | 1904 | 6/30- | Wellsville Oil Drillers | Southern Tier League | , | |
| W. A. Edwards | edward002w-- | 1904 | 64 g. | Fargo | Northern League | , | |
| Walter Edwards | 1904 | Hartford Senators | Connecticut State League | , | |||
| Harry Eells | eells-001har | 1904 | 50 g. | Joplin Miners | Missouri Valley League | , | |
| Harry Eells | eells-001har | 1904 | 8/28-9/18 | Kansas City Blues | American Association | , | |
| Dick Egan | egan--001ric | 1904 | , | ||||
| Dick Egan | egan--001ric | 1904 | 43 g. | Superior Longshoremen | Northern League | , | |
| Dick Egan | egan--001ric | 1904 | Bismarck ND | Independent | , | ||
| Jack Egan | egan--001rip | 1904 | 4/29-9/28 | Umpire | Eastern League | , | |
| Ned Egan | egan--001edw | 1904 | no g. | Winnipeg Maroons | Northern League | , | |
| Wish Egan | egan--001alo | 1904 | 4/21-9/18 | Louisville Colonels | American Association | , | |
| Friedrich Eggers | eggers001fre | 1904 | Vicksburg Hill Billies | Cotton States League | , | ||
| Friedrich Eggers | eggers001fre | 1904 | Yazoo City Zoos | Delta League | , | ||
| Charles Eggert | eggert001cha | 1904 | Piqua OH | Independent | , | ||
| Charles Eggert | eggert001cha | 1904 | Lima OH | Independent | , | ||
| Charles Eggert | eggert001cha | 1904 | 10 g. | Savannah Pathfinders | South Atlantic League | , | |
| Ray Egner | egner-001ray | 1904 | Tren-YMCA | Independent | , | ||
| Fred Ehman | ehman-001fre | 1904 | Little Rock Travelers | Southern Association | , | ||
| Fred Ehman | ehman-001fre | 1904 | 37 g. | Akron OH | Independent | , | |
| Red Ehret | ehret-001phi | 1904 | 4/28-9/20 | Memphis Egyptians | Southern Association | , | |
| Charles Eichberger | eichbe001cha | 1904 | Hobart College | College | , | ||
| Charles Eichberger | eichbe001cha | 1904 | 5/28- | Cloudersport PA | Independent | , | |
| Charles Eichberger | eichbe001cha | 1904 | 8/24-9/8 | Coudersport | Southern Tier League | , | |
| John Eicherly | eicher000joh | 1904 | York Penn Parks | Tri-State League | , | ||
| Harry Eichler | eichle001har | 1904 | 76 g. | Warren PA | Independent | , | |
| Joseph Eisenloh | 1904 | Chambersburg | Independent | , | |||
| Henry Eldred | eldred001hen | 1904 | 26 g. | Brookhaven | Delta League | , | |
| Aaron Eldridge | eldrid000aar | 1904 | Umpire | South Texas League | , | ||
| Frank Eley | eley--001fra | 1904 | 421 ab | Hudson Marines | Hudson River League | , | |
| Charles Ellinor | 1904 | +9/6+ | FtSm-Devils | Independent | , | ||
| Claude Elliott | elliot001cla | 1904 | 4/16- | 9 g. | Cincinnati | National League | Cincinnati, OH |
| Claude Elliott | elliot001cla | 1904 | 3 g. | New York | National League | New York, NY | |
| Edwin Elliott | elliot005cha | 1904 | 5/2-5/17 | Concord Marines | New England League | , | |
| L. A. Elliott | elliot001l-- | 1904 | 7/23-7/30 | Corsicana Oil Citys | Texas League | , | |
| Ben Ellis | ellis-003ben | 1904 | 5/6-7/4 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Ben Ellis | ellis-003ben | 1904 | 7/6-9/17 | Troy Trojans | New York State League | , | |
| Eli Ellis | ellis-001eli | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| Elmer | elmer-001--- | 1904 | 43 g. | Brookhaven | Delta League | , | |
| Charles Elsey | elsey-001cha | 1904 | 123 g. | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Charles Elsey | elsey-001cha | 1904 | Boise Fruit Pickers | Pacific National League | , | ||
| Charles Elston | elston001cur | 1904 | 43 g. | Newark OH | Independent | , | |
| Charles Elston | elston001cur | 1904 | +7/8+ | Zanesville OH | ProtAssn | , | |
| Bert Eltom | eltom-001alb | 1904 | +6/9-6/16+ | Dollar Bay | Copper Country League | , | |
| William Elwert | elwert001wil | 1904 | Toledo Mud Hens | American Association | , | ||
| Ely | 1904 | Joplin Miners | Missouri Valley League | , | |||
| Bones Ely | ely---001wil | 1904 | Portland Browns | Pacific Coast League | , | ||
| Jack Ely | ely---001joh | 1904 | 4/22-9/15 | Atlanta Crackers | Southern Association | , | |
| Thomas Embleton | 1904 | Burlington | Northern New York League | , | |||
| Elmer Emerson | emerso002elm | 1904 | San Jose | California State League | , | ||
| Elmer Emerson | emerso002elm | 1904 | 6/12-7/4 | Salem Raglands | Oregon State League | , | |
| Elmer Emerson | emerso002elm | 1904 | 1 g. | Oakland Oaks | Pacific Coast League | , | |
| Elmer Emerson | emerso002elm | 1904 | +7/1-7/7+ | Tacoma Tigers | Pacific Coast League | , | |
| Elmer Emerson | emerso002elm | 1904 | 7/24-9/4 | Hoquiam Perfect Gentlemen | Southwest Washington League | , | |
| Ernest Endres | 1904 | Lea.-Brandon | Independent | , | |||
| Gustave Eng | eng---001gus | 1904 | RoIsl-Independents | Independent | , | ||
| George Engel | engel-002geo | 1904 | 79 g. | Columbia Skyscrapers | South Atlantic League | , | |
| Arthur Engle | engle-001art | 1904 | 4/28-5/17 | Dayton Veterans | Central League | , | |
| Arthur Engle | engle-001art | 1904 | 5/20-5/26 | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |
| Arthur Engle | engle-001art | 1904 | 94 g. | Augusta Tourists | South Atlantic League | , | |
| Clyde Enslow | enslow001cly | 1904 | +6/25+ | Shelby OH | Independent | , | |
| Clyde Enslow | enslow001cly | 1904 | +7/4+ | Chic. Junction OH | Independent | , | |
| Eonghesgy | eonghe000--- | 1904 | 8/11 | Penn Yan Grape Pickers | Southern Tier League | , | |
| Edward Erickson | ericks002edw | 1904 | Winnipeg Maroons | Northern League | , | ||
| Albert Erle | erle--002alb | 1904 | San Jose | California State League | , | ||
| Albert Erle | erle--002alb | 1904 | San Francisco | California State League | , | ||
| Albert Erle | erle--002alb | 1904 | 3 g. | Tacoma Tigers | Pacific Coast League | , | |
| John Ernst | ernst-001j-- | 1904 | 6/29-9/10 | Corning White Ponies | Southern Tier League | , | |
| John Ernst | ernst-001j-- | 1904 | Steelton YMCA | , | |||
| Joseph Erwin | erwin-001jos | 1904 | Oklahoma City Mets | Southwestern League | , | ||
| Joseph Erwin | erwin-001jos | 1904 | +5/19-8/3+ | Sheffield | Tennessee-Alabama League | , | |
| Joseph Erwin | erwin-001jos | 1904 | 17 g. | Houston Wanderers | South Texas League | , | |
| Ross/Joe? Erwin | 1904 | 7/8-8/4 | Corsicana Oil Citys | Texas League | , | ||
| Tex Erwin | erwin-001ros | 1904 | g. ? | Galveston Sand Crabs | South Texas League | , | |
| Joseph Essenter | 1904 | , | |||||
| Bill Essick | essick002wil | 1904 | 48 g. | Salt Lake City Elders | Pacific National League | , | |
| Elmer Essler | essler001elm | 1904 | 5/3-6/17 | Camden | Tri-State League | , | |
| John Eubank | eubank001joh | 1904 | +5/10-9/5 | Fort Dodge Gypsum Eaters | Iowa League | , | |
| Jacob Eul | eul---001jac | 1904 | Davenport River Rats | Illinois-Indiana-Iowa League | , | ||
| Frank Eustace | eustac003fra | 1904 | Concord Marines | New England League | , | ||
| Frank Eustace | eustac003fra | 1904 | 5/10-9/27 | York Penn Parks | Tri-State League | , | |
| Evans | 1904 | 7 g. | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | ||
| Bruce Evans | evans-001bru | 1904 | 5/6-5/22+ | Oskaloosa Quakers | Iowa League | , | |
| Roy Evans | evans-001roy | 1904 | 5/11-8/4 | Williamsport Millionaires | Tri-State League | , | |
| Roy Evans | evans-001roy | 1904 | 8/8-8/11 | Wilmington Peaches | Tri-State League | , | |
| Roy Evans | evans-001roy | 1904 | 9/6 | York Penn Parks | Tri-State League | , | |
| Will Evans | evans-004wil | 1904 | 5/17 | Shreveport Pirates | Southern Association | , | |
| Will Evans | evans-004wil | 1904 | 5/24-9/24 | Little Rock Travelers | Southern Association | , | |
| William Evans | 1904 | Umpire | Pennsylvania Ohio League | , | |||
| William Everett | everet002wil | 1904 | 41 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| William Everett | everet002wil | 1904 | +6/21-9/5 | Ottumwa Standpatters | Iowa League | , | |
| Frank Everhart | everha001fra | 1904 | 4/30-9/2 | Beaumont Millionaires | South Texas League | , | |
| Bill Everitt | everet001wil | 1904 | , | ||||
| Jack Evers | evers-001joh | 1904 | 5/6-9/19 | Albany Senators | New York State League | , | |
| Bert Everson | everso001a-- | 1904 | 5/5-8/4 | Wilmington Peaches | Tri-State League | , | |
| Elwood Eyler | eyler-001elw | 1904 | 4/24-9/25 | Denver Grizzlies | Western League | , | |
| Jim Fairbank | fairba001jam | 1904 | 4/30-9/5 | Providence Grays | Eastern League | , | |
| Jim Fairbank | fairba001jam | 1904 | -10/8 | 3 g. | Philadelphia | American League | Philadelphia, PA |
| Cy Falkenberg | falken001fre | 1904 | 40 g. | Toronto Maple Leafs | Eastern League | , | |
| Patrick Fallon | fallon000pat | 1904 | 6/29-7/24 | Elmira | Southern Tier League | , | |
| Patrick Fallon | fallon000pat | 1904 | Kane PA | Independent | , | ||
| Leonard Fanning | fannin002l-- | 1904 | Leavenworth Orioles | Missouri Valley League | , | ||
| Andrew Farley | farley001and | 1904 | Kingston Colonials | Hudson River League | , | ||
| Ed Farley | farley001edw | 1904 | 5/9-6/20 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Ed Farley | farley001edw | 1904 | 7/1-9/17 | Binghamton Bingoes | New York State League | , | |
| Alex Farmer | farmer001ale | 1904 | 7/15-8/1 | Utica Pent-Ups | New York State League | , | |
| Alex Farmer | farmer001ale | 1904 | 8/8-8/15 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| T.? Farmer | farmer002--- | 1904 | 19 g. | Jackson Senators | Delta League | , | |
| Farrell | farrel005--- | 1904 | 9 g. | Springfield Midgets | Missouri Valley League | , | |
| Farrell | 1904 | 38 g. | Ashland | Independent | , | ||
| Farrell | 1904 | Newark OH | Independent | , | |||
| Bernard Farrell | farrel001ber | 1904 | 5/1-9/10 | Grand Rapids Orphans | Central League | , | |
| Charles Farrell | farrel005--- | 1904 | 9 g. | Springfield Midgets | Missouri Valley League | , | |
| Charles Farrell | farrel005--- | 1904 | Springdale Ark | Independent | , | ||
| Frank Farrell | farrel002fra | 1904 | 5/1-5/11 | Harrisburg Senators | Tri-State League | , | |
| Frank Farrell | farrel002fra | 1904 | 6/17-9/10 | Wilmington Peaches | Tri-State League | , | |
| Jack Farrell | 1904 | 5/14- | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | ||
| John Farrell | farrel006joh | 1904 | St. Louis | National League | St. Louis, MO | ||
| Albert Farris | farris001law | 1904 | 5/16-8/20 | Huntsville | Tennessee-Alabama League | , | |
| Frank Farris | farris001fra | 1904 | Denton TX | Independent | , | ||
| Fassett | fasset001--- | 1904 | 1 g. | Columbia | Tennessee-Alabama League | , | |
| Paul Faucett | faucet001--- | 1904 | 6/30-7/4 | Nashville Volunteers | Southern Association | , | |
| Paul Faucett | faucet001--- | 1904 | Greenville Cotton Pickers | Cotton States League | , | ||
| J. W. Faulkner | 1904 | Southwestern League | , | ||||
| J. W. Faulkner | 1904 | Guthrie Blues | Southwestern League | , | |||
| Oliver Faulkner | faulkn001oli | 1904 | 5/2-8/12 | Rochester Bronchos | Eastern League | , | |
| Oliver Faulkner | faulkn001oli | 1904 | 8/26-8/31 | Wilmington Peaches | Tri-State League | , | |
| Henry Faust | 1904 | 49 g. | Warren OH | Independent | , | ||
| Fawcett | 1904 | +9/7+ | Grinnell College | College | , | ||
| Edward Fay | fay---001edw | 1904 | Kingston Colonials | Hudson River League | , | ||
| Joe Fay | fay---001jos | 1904 | 4/29-7/4 | Salem Raglands | Oregon State League | , | |
| Jim Feeney | feeney002jam | 1904 | Oakland | , | |||
| Jim Feeney | feeney002jam | 1904 | 4/28-9/9 | Terre Haute Hottentots | Central League | , | |
| L. Feeney | feeney001l-- | 1904 | Lodi | California State League | , | ||
| Feeny | 1904 | 8 g. | Findlay OH | Independent | , | ||
| William Fehl | fehl--001--- | 1904 | 8/13-9/1 | Terre Haute Hottentots | Central League | , | |
| Homer Feild | 1904 | 7/18-7/30 | Dallas Giants | Texas League | , | ||
| Homer Feild | 1904 | 8/1-8/14 | Corsicana Oil Citys | Texas League | , | ||
| Feine | 1904 | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |||
| Harry Feldhaus | feldha001har | 1904 | 4/28-9/24 | Nashville Volunteers | Southern Association | , | |
| Harry Felix | felix-001har | 1904 | Louisville Colonels | American Association | , | ||
| Matthias Fennell | fennel001mat | 1904 | U. of Pennsylvania | College | , | ||
| Matthias Fennell | fennel001mat | 1904 | 7/1-9/8 | Elmira | Southern Tier League | , | |
| Roy Fennell | 1904 | Purdue Univ. | College | , | |||
| Roy Fennell | 1904 | +7/1+ | Altoona PA | Independent | , | ||
| Cecil Ferguson | fergus002geo | 1904 | 4/29-9/7 | South Bend Greens | Central League | , | |
| Cecil Ferguson | fergus002geo | 1904 | 9/11-9/15 | Louisville Colonels | American Association | , | |
| Charlie Ferguson | fergus002cha | 1904 | 5/3-9/5 | St. Paul Saints | American Association | , | |
| Frank Ferguson | fergus001fra | 1904 | Stockton | California State League | , | ||
| James Ferguson | fergus006jam | 1904 | Chester | Pennsylvania League | , | ||
| James Ferguson | fergus006jam | 1904 | 56 g. | Hartford Senators | Connecticut State League | , | |
| Jack Ferrell | ferrel001jac | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | ||
| Robert Ferrell | ferrel003rob | 1904 | 26 g. | Coshocton OH | Independent | , | |
| Robert Ferrell | ferrel003rob | 1904 | Lancaster OH | Independent | , | ||
| Emanuel Ferrias | ferria001e-- | 1904 | 4/30-9/10 | South Bend Greens | Central League | , | |
| Win Ferrin | ferrin001win | 1904 | 10 g. | Salt Lake City Elders | Pacific National League | , | |
| George Ferris | ferris001geo | 1904 | 127 g. | Spokane Indians | Pacific National League | , | |
| James Ferris | ferris001jam | 1904 | 7/15-9/17 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Cy Ferry | ferry-001alf | 1904 | 5/12- | 3 g. | Detroit | American League | Detroit, MI |
| Cy Ferry | ferry-001alf | 1904 | 6/13-9/20 | Minneapolis Millers | American Association | , | |
| Ed Fertsch | fertsc001edw | 1904 | 5/1-9/28 | Rochester Bronchos | Eastern League | , | |
| H. Claude Fetz | fetz--002cla | 1904 | -6/30 | Enid Evangelists | Southwestern League | , | |
| H. Claude Fetz | fetz--002cla | 1904 | 7/1-7/6 | Dallas Giants | Texas League | , | |
| H. Claude Fetz | fetz--002cla | 1904 | 7/11-7/26 | Corsicana Oil Citys | Texas League | , | |
| H. Claude Fetz | fetz--002cla | 1904 | 7/29-7/31 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Willy Fetzer | fetzer001--- | 1904 | Asheville NC | Independent | , | ||
| Fewrguson | 1904 | 15 ab | Monroe Hill Citys | Cotton States League | , | ||
| George Feye | feye--001geo | 1904 | Monroe Hill Citys | Cotton States League | , | ||
| George Feye | feye--001geo | 1904 | 6/5-9/14 | Shreveport Pirates | Southern Association | , | |
| Fields | 1904 | Meriden Silverites | Connecticut State League | , | |||
| Fields | 1904 | 9/5 | Albany Senators | New York State League | , | ||
| Homer Fields | fields001hom | 1904 | 25 g. | Dallas Giants | Texas League | , | |
| Homer Fields | fields001hom | 1904 | Corsicana Oil Citys | Texas League | , | ||
| Meyer Fields | fields000mey | 1904 | 5/2-5/7 | Fall River Indians | New England League | , | |
| Meyer Fields | fields000mey | 1904 | Norwich Reds | Connecticut State League | , | ||
| Lou Fiene | fiene-001lou | 1904 | 31 g. | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |
| Jack Fifield | fifiel001jac | 1904 | 5/9-9/13 | Syracuse Stars | New York State League | , | |
| Frank Figgemeier | figgem002fra | 1904 | +5/30+ | Umpire | American Association | , | |
| Jack Fillman | fillma001joh | 1904 | 122 g. | Joplin Miners | Missouri Valley League | , | |
| Jack Fillman | fillma001joh | 1904 | 9/17-9/18 | Kansas City Blues | American Association | , | |
| Fillmore | fillmo003--- | 1904 | +6/27-6/29+ | Oskaloosa Quakers | Iowa League | , | |
| Milton Fink | fink--001mil | 1904 | 5/8-7/31 | Olympia Senators | Southwest Washington League | , | |
| Billy Finn | finn--001wil | 1904 | +8/11-8/13+ | Harrisburg Senators | Tri-State League | , | |
| Billy Finn | finn--001wil | 1904 | New London Whalers | Connecticut State League | , | ||
| Mickey Finn | finn--001duk | 1904 | 4/21-9/25 | Little Rock Travelers | Southern Association | , | |
| Patrick Finnigan | 1904 | Winnipeg Maroons | Northern League | , | |||
| Al. Fischer | 1904 | Logansport IN | , | ||||
| William Fischman | fischm001wil | 1904 | 5/3-6/17 | Camden | Tri-State League | , | |
| Fish | 1904 | 6 g. | Coshocton OH | Independent | , | ||
| Fiske? Fish | 1904 | 22 g. | Fort Dodge Gypsum Eaters | Iowa League | , | ||
| Leslie Fish | fish--002les | 1904 | Hudson Marines | Hudson River League | , | ||
| Fisher | fisher042--- | 1904 | +5/18+ | 2 g. | Knoxville | Tennessee-Alabama League | , |
| Fisher | fisher059--- | 1904 | 9/10 | Rochester Bronchos | Eastern League | , | |
| Charles Fisher | fisher009cha | 1904 | Newburgh Taylor-mades | Hudson River League | , | ||
| Harry Fisher | fisher004har | 1904 | 5/17-9/10 | Altoona Mountaineers | Tri-State League | , | |
| Harry Fisher | fisher004har | 1904 | no g. | Evansville River Rats | Central League | , | |
| Ike Fisher | fisher001ike | 1904 | 4/21-9/7 | Nashville Volunteers | Southern Association | , | |
| John Fisher | fisher007joh | 1904 | 4/23-9/19 | Indianapolis Indians | American Association | , | |
| Michael Fisher | fisher001mic | 1904 | Tacoma Tigers | Pacific Coast League | , | ||
| Tom Fisher | fisher002tho | 1904 | 4/17-10/3 | Boston | National League | Boston, MA | |
| Tom Fisher | fisher001tho | 1904 | 5/16-7/29 | Huntsville | Tennessee-Alabama League | , | |
| Walter Fisher | fisher001bat | 1904 | 5/-8/20 | Chattanooga | Tennessee-Alabama League | , | |
| Roy Fiske | fiske-001roy | 1904 | 5/19-7/29 | Des Moines Prohibitionists | Western League | , | |
| Roy Fiske | fiske-001roy | 1904 | 8/4-8/9 | Marshalltown Grays | Iowa League | , | |
| Roy Fiske | fiske-001roy | 1904 | 8/30-9/5 | Fort Dodge Gypsum Eaters | Iowa League | , | |
| Roy Fiske | fiske-001roy | 1904 | 9/16-9/25 | Des Moines Prohibitionists | Western League | , | |
| Roy? Fiske | 1904 | +7/22-7/24+ | Rock Island Islanders | Illinois-Indiana-Iowa League | , | ||
| John Fitzgerald | fitzge004joh | 1904 | 39 g. | Tacoma Tigers | Pacific Coast League | , | |
| John Fitzhenry | fitzhe004--- | 1904 | 6/8- | Corning NY | Independent | , | |
| John Fitzhenry | fitzhe004--- | 1904 | -6/17 | Elmira NY | Independent | , | |
| John Fitzhenry | fitzhe004--- | 1904 | 8/23-8/31 | Rochester Bronchos | Eastern League | , | |
| Billy Fitzmaurice | fitzma001wil | 1904 | 112 g. | New Haven Blues | Connecticut State League | , | |
| Fitzpatrick | 1904 | 5/20-5/25 | Dayton Veterans | Central League | , | ||
| Frank Fitzpatrick | fitzpa001fra | 1904 | 106 g. | Holyoke Paperweights | Connecticut State League | , | |
| Pat Flaherty | flaher005pat | 1904 | 5/1-5/23+ | Oklahoma City Mets | Southwestern League | , | |
| Pat Flaherty | flaher005pat | 1904 | Guthrie Blues | Southwestern League | , | ||
| Pat Flaherty | flaher005pat | 1904 | postseason | Coffeyville KS | Independent | , | |
| Patsy Flaherty | flaher004pat | 1904 | 5 g. | Chicago | American League | Chicago, IL | |
| Patsy Flaherty | flaher004pat | 1904 | 36 g. | Pittsburgh | National League | Pittsburgh, PA | |
| Peter Flaherty | flaher000pet | 1904 | 5/20-6/1 | Lawrence Colts | New England League | , | |
| Flanagan | flanag011--- | 1904 | 5/1 | Rochester Bronchos | Eastern League | , | |
| Flanagan | 1904 | 8/20-8/25 | Binghamton Bingoes | New York State League | , | ||
| Steamer Flanagan | flanag003jam | 1904 | Meriden Silverites | Connecticut State League | , | ||
| Steamer Flanagan | flanag003jam | 1904 | 119 g. | Springfield Ponies | Connecticut State League | , | |
| Stephen Flanagan | flanag001ste | 1904 | 4/30-9/19 | Lawrence Colts | New England League | , | |
| Jack Flannery | flanne001joh | 1904 | 4/30-5/10 | Grand Rapids Orphans | Central League | , | |
| Jack Flannery | flanne001joh | 1904 | 6/8- | 29 g. | Boise Fruit Pickers | Pacific National League | , |
| Jack Flannery | flanne001joh | 1904 | +7/30- | Umpire | Pacific National League | , | |
| Jack Flater | flater001joh | 1904 | 5/6-9/16 | Albany Senators | New York State League | , | |
| William Fleet | fleet-001wil | 1904 | 5/3-9/11 | Terre Haute Hottentots | Central League | , | |
| Ikey Fleischman | 1904-05 | U. Georgia | College | , | |||
| Fleming | 1904 | 5/25 | Wilmington Peaches | Tri-State League | , | ||
| Chuck Fleming | flemin002cha | 1904 | 5/7-9/11 | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| Ed. Fleming | flemin001e-- | 1904 | 5/7-9/5 | Burlington River Rats | Iowa League | , | |
| Harry Fleming | flemin002har | 1904 | 90 g. | Clarksdale | Delta League | , | |
| Harry Fleming | flemin002har | 1904 | 9/5- | Cairo Champions | Kentucky-Illinois-Tennessee League | , | |
| Patrick Fleming | flemin000pat | 1904 | 7/6-7/7 | Haverhill Hustlers | New England League | , | |
| Ralph Fleming | 1904 | 7/25-7/27 | Marion Oilworkers/Peoria Distillers | Central League | , | ||
| Ralph Fleming | 1904 | 7/29-8/15 | Evansville River Rats | Central League | , | ||
| Tom Fleming | flemin003tho | 1904 | -5/4 | 3 g. | Philadelphia | National League | Philadelphia, PA |
| Tom Fleming | flemin003tho | 1904 | 5/30-9/25 | Sioux City Soos | Western League | , | |
| Flick | 1904 | 21 g. | Newark OH | Independent | , | ||
| Flick | 1904 | 9 g. | Akron OH | Independent | , | ||
| Arnold Flint | 1904 | Evansville River Rats | Central League | , | |||
| Tim Flood | flood-001tim | 1904 | 209 g. | Los Angeles Angels | Pacific Coast League | , | |
| Jack Flournoy | flourn001joh | 1904 | 4/29-7/4 | Rochester Bronchos | Eastern League | , | |
| Jack Flournoy | flourn001joh | 1904 | 7/9-9/20 | St. Paul Saints | American Association | , | |
| Flynn | 1904 | 6/2-6/3 | Schenectady Electricians/Scranton Miners | New York State League | , | ||
| John Flynn | 1904 | 5/6-7/6 | Umpire | Iowa League | , | ||
| John Flynn | 1904 | Umpire | Missouri Valley League | , | |||
| John Flynn | 1904-06 | Holy Cross Col | College | , | |||
| Michael Flynn | flynn-003mic | 1904 | 4/26 | Salt Lake City Elders | Pacific National League | , | |
| Michael Flynn | flynn-003mic | 1904 | 6/30-7/1 | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Michael Flynn | flynn-003mic | 1904 | Evanstown | Utah Wyoming | , | ||
| Mickey Flynn | flynn-006mic | 1904 | Springfield Ponies | Connecticut State League | , | ||
| Mike Flynn | flynn-002mic | 1904 | 5/6-8/19 | Umpire | Iowa League | , | |
| Fogarty | 1904 | 9/16 | Utica Pent-Ups | New York State League | , | ||
| Thomas Fogarty | fogart001tho | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| Thomas Fogarty | fogart001tho | 1904 | 6/20-7/8 | Binghamton Bingoes | New York State League | , | |
| Thomas Fogarty | fogart001tho | 1904 | 8/18-9/17 | Binghamton Bingoes | New York State League | , | |
| Lee Fohl | fohl--001leo | 1904 | 111 g. | Homestead PA | Independent | , | |
| Patrick Foley | foley-002pat | 1904 | 7/29-9/17 | Lawrence Colts | New England League | , | |
| Forbes | forbes003--- | 1904 | 5/5-6/3 | Lawrence Colts | New England League | , | |
| Ford | ford--037--- | 1904 | 4/30 | New Bedford Whalers | New England League | , | |
| Ford | ford--041--- | 1904 | 5/12 | Eugene Blues | Oregon State League | , | |
| Bud Ford | 1904 | Macon Highlanders | South Atlantic League | , | |||
| Eddie Ford | ford--001edw | 1904 | 5/8-5/29 | Centralia Midgets | Southwest Washington League | , | |
| Eddie Ford | ford--001edw | 1904 | 6/19-9/4 | Hoquiam Perfect Gentlemen | Southwest Washington League | , | |
| Gene Ford | ford--002eug | 1904 | 4/29-9/19 | Minneapolis Millers | American Association | , | |
| Henry Ford | ford--001hen | 1904 | 17 g. | Leavenworth Orioles | Missouri Valley League | , | |
| James Ford | ford--002jam | 1904 | 80 g. | Yazoo City Zoos | Delta League | , | |
| Thomas Ford | ford--003tom | 1904 | New Bedford Whalers | New England League | , | ||
| Thomas Ford | ford--003tom | 1904 | 6/30-7/29+ | Wellsville Oil Drillers | Southern Tier League | , | |
| Thomas Ford | ford--003tom | 1904 | 8/2-8/5 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Thomas Ford | ford--003tom | 1904 | 9/5-9/9 | Addison White Sox | Southern Tier League | , | |
| Tim Ford | ford--001new | 1904 | 5/16-8/20 | Chattanooga | Tennessee-Alabama League | , | |
| Ed Forde | forde-001--- | 1904 | +7/29+ | Grand Forks Forkers | Northern League | , | |
| Frank Foreman | forema001fra | 1904 | no g. | Baltimore Orioles | Eastern League | , | |
| Frank Foreman | forema001fra | 1904 | Roxborough PA | Independent | , | ||
| Frank Foreman | forema001fra | 1904 | 7/1-7/26 | Wilmington Peaches | Tri-State League | , | |
| John Foreman | forema001bro | 1904 | 5/10-8/26 | York Penn Parks | Tri-State League | , | |
| John Foreman | forema001bro | 1904 | +9/30 | Harrisburg Senators | Tri-State League | , | |
| Carl Forkum | forkum002--- | 1904 | Penn State Univ | College | , | ||
| Forshaw | forsha001--- | 1904 | +7/8-8/2 | Columbia | Tennessee-Alabama League | , | |
| Henry Forsythe | forsyt001hen | 1904 | California | California State League | , | ||
| Henry Forsythe | forsyt001hen | 1904 | 44 g. | Spokane Indians | Pacific National League | , | |
| Henry Forsythe | forsyt001hen | 1904 | Salt Lake City Elders | Pacific National League | , | ||
| Foster | foster030--- | 1904 | 12 g. | Brookhaven | Delta League | , | |
| Clarence Foster | foster001cla | 1904 | 109 g. | Bridgeport Orators | Connecticut State League | , | |
| H. Foster | foster001h-- | 1904 | 79 g. | Jackson Senators | Delta League | , | |
| William Foster | foster003wil | 1904 | Superior Longshoremen | Northern League | , | ||
| William Foster | foster003wil | 1904 | Bismarck ND | Independent | , | ||
| William Foster | foster003wil | 1904 | 8/12-8/26+ | Lake Linden Lakers | Copper Country League | , | |
| Foulke | 1904 | 6/24-6/29 | Troy Trojans | New York State League | , | ||
| George Foulke | 1904 | Lebanon PA | Independent | , | |||
| Jimmy Foulks | foulks001jam | 1904 | 5/19- | 23 g. | Fargo | Northern League | , |
| Jimmy Foulks | foulks001jam | 1904 | +8/21+ | Calumet Aristocrats | Copper Country League | , | |
| Fowler | 1904 | 33 g. | Sharon PA | Independent | , | ||
| R. Frank Fowler | 1904 | Bessemer | Tennessee-Alabama League | , | |||
| Fox | fox---001aug | 1904 | 5/6-7/14 | Troy Trojans | New York State League | , | |
| Fox | fox---001aug | 1904 | 7/18-9/18 | Albany Senators | New York State League | , | |
| Fox | 1904 | 5/29 | Binghamton Bingoes | New York State League | , | ||
| Bill Fox | fox---006wil | 1904 | 4/20-9/20 | Minneapolis Millers | American Association | , | |
| Charley Fox | fox---003cha | 1904 | 5/14-9/12 | Grand Rapids Orphans | Central League | , | |
| Charley Fox | 1904 | 7/24- | Camden NJ | Independent | , | ||
| George Fox | fox---001pad | 1904 | 4/23-9/23 | New Orleans Pelicans | Southern Association | , | |
| George Fox | fox---003geo | 1904 | 16 g. | Albany Senators | New York State League | , | |
| Jack Fox | fox---004joh | 1904 | 5/5-9/18 | Utica Pent-Ups | New York State League | , | |
| Jim Fox | fox---001jam | 1904 | 4/30-7/30 | Wheeling Stogies | Central League | , | |
| Jim Fox | fox---001jam | 1904 | +8/10-8/17 | Knoxville | Tennessee-Alabama League | , | |
| John Fox | fox---001joh | 1904 | 4/30-7/29 | Wheeling Stogies | Central League | , | |
| John Fox | fox---001joh | 1904 | no g. | Knoxville | Tennessee-Alabama League | , | |
| John Fox | fox---001joh | 1904 | +9/16+ | Knoxville TN | Independent | , | |
| Bill Foxen | foxen-001wil | 1904 | 5/2-5/9 | Jersey City Skeeters | Eastern League | , | |
| Bill Foxen | foxen-001wil | 1904 | 46 g. | Hartford Senators | Connecticut State League | , | |
| Bill Foxen | foxen-001wil | 1904 | Hoboken NJ | Independent | , | ||
| Leon Foy | foy---002leo | 1904 | 4/28-7/18 | Dayton Veterans | Central League | , | |
| Leon Foy | foy---002leo | 1904 | 7/20-9/6 | Evansville River Rats | Central League | , | |
| Leon Foy | foy---002leo | 1904 | 9/7-9/11 | Terre Haute Hottentots | Central League | , | |
| Walter Foye | foye--001wal | 1904 | 8/17-8/22 | Lowell Tigers | New England League | , | |
| William Frakes | frakes000bil | 1904 | 10 g. | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |
| Walter Frambes | 1904 | +9/5+ | Pleasantville NJ | Independent | , | ||
| E. E. France | 1904 | +7/22+ | Kent OH | Independent | , | ||
| Ike Francis | franci002isa | 1904 | Portland Browns | Pacific Coast League | , | ||
| Ike Francis | franci002isa | 1904 | 7/25-9/28 | Toronto Maple Leafs | Eastern League | , | |
| John Francis | 1904 | 6/26 | Corsicana Oil Citys | Texas League | , | ||
| Buck Francks | franck001cha | 1904 | 204 g. | Oakland Oaks | Pacific Coast League | , | |
| Charlie Frank | frank-003cha | 1904 | 4/121-9/25 | Memphis Egyptians | Southern Association | , | |
| Eddie Frank | frank-001edw | 1904 | 5/6-9/17 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Eddie Frank | frank-001edw | 1904 | Roch.-Navals | Rochester Indoor League | , | ||
| George Frank | frank-001geo | 1904 | +5/10-7/8+ | Fort Dodge Gypsum Eaters | Iowa League | , | |
| George Frank | frank-001geo | 1904 | Roch.-Navals | Rochester Indoor League | , | ||
| J. Frantz | frantz001j-- | 1904 | Enid Evangelists | Southwestern League | , | ||
| Orville Frantz | frantz002--- | 1904 | Harvard Univ | College | , | ||
| Walter Frantz | frantz001wal | 1904 | +6/20+ | Wellington KS | Independent | , | |
| Walter Frantz | frantz001wal | 1904 | Fairmount College | College | , | ||
| Walter Frantz | frantz001wal | 1904 | Enid Evangelists | Southwestern League | , | ||
| Walter Frantz | frantz001wal | 1904 | 7/19-9/20 | Kansas City Blues | American Association | , | |
| Ralph Frary | frary-001ral | 1904 | 125 g. | Spokane Indians | Pacific National League | , | |
| Ralph Frary | frary-001ral | 1904 | 21 g. | Portland Browns | Pacific Coast League | , | |
| Frazee | 1904 | 7/28 | Corsicana Oil Citys | Texas League | , | ||
| Dotty Freck | freck-001cha | 1904 | 4/28-8/2 | Terre Haute Hottentots | Central League | , | |
| Otto Fredericks | freder001ott | 1904 | 125 g. | Fort Scott Giants | Missouri Valley League | , | |
| Theodore Frederickson | freder001the | 1904 | 5/15- | Green Bay WI | Independent | , | |
| Theodore Frederickson | freder001the | 1904 | Iron Mt. MI | Independent | , | ||
| Freeman | freema039--- | 1904 | +5/10-5/29+ | Burlington River Rats | Iowa League | , | |
| Freeman | freema018--- | 1904 | Greenville Cotton Pickers | Cotton States League | , | ||
| Freeman | freema008--- | 1904 | 44 g. | Canton | Delta League | , | |
| Buck Freeman | freema003joh | 1904 | 157 g. | Boston | American League | Boston, MA | |
| George Freeman | freema001geo | 1904 | 13 g. | Superior Longshoremen | Northern League | , | |
| James Freeman | freema004jam | 1904 | 5/11- | 22+ g. | Paducah Indians | Kentucky-Illinois-Tennessee League | , |
| James Freeman | freema004jam | 1904 | 6/29-7/2 | Nashville Volunteers | Southern Association | , | |
| Jerry Freeman | freema001fra | 1904 | Portland Browns | Pacific Coast League | , | ||
| Jerry Freeman | freema001fra | 1904 | Seattle Siwashes | Pacific Coast League | , | ||
| Jerry Freeman | freema001fra | 1904 | 7/6-9/20 | Minneapolis Millers | American Association | , | |
| Harry Freese | freese001har | 1904 | 4/26-9/21 | Omaha Rangers | Western League | , | |
| Tony Fremer | fremer001ant | 1904 | 4/24-8/28 | Sioux City Soos | Western League | , | |
| Tony Fremer | fremer001ant | 1904 | 9/17-9/25 | Des Moines Prohibitionists | Western League | , | |
| Win French | french001win | 1904 | 4/24-5/2 | Montgomery Senators | Southern Association | , | |
| Win French | french001win | 1904 | 5/10-9/25 | New Orleans Pelicans | Southern Association | , | |
| Frank Frey | frye--001t-- | 1904 | 4/30-5/14 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Ernest Frick | frick-001jam | 1904 | 106 g. | Iola Gasbags | Missouri Valley League | , | |
| George Frickie | fricki001geo | 1904 | 13 g. | Canton | Delta League | , | |
| George Frickie | fricki001geo | 1904 | Nashville Volunteers | Southern Association | , | ||
| Bill Friel | friel-001wil | 1904 | 4/20-9/18 | Columbus Senators | American Association | , | |
| Jack Friel | friel-001j-- | 1904 | 105 g. | Pittsburg Coal Diggers | Missouri Valley League | , | |
| Jack Friel | friel-001j-- | 1904 | Topeka Saints | Missouri Valley League | , | ||
| Jack Friel | friel-001j-- | 1904 | Sedalia Goldbugs | Missouri Valley League | , | ||
| Danny Friend | friend002dan | 1904 | 4/30-9/19 | New Bedford Whalers | New England League | , | |
| Charlie Frisbee | frisbe001cha | 1904 | 4/20-9/19 | Toledo Mud Hens | American Association | , | |
| Emil Frisk | frisk-001joh | 1904 | 219 g. | Seattle Siwashes | Pacific Coast League | , | |
| Charlie Fritz | fritz-001cha | 1904 | Vicksburg Hill Billies | Cotton States League | , | ||
| Emile Fritz | fritz-001emi | 1904 | 4/23-9/24 | Memphis Egyptians | Southern Association | , | |
| Edward Frome | from--002edw | 1904 | 5/6-9/5 | Fort Dodge Gypsum Eaters | Iowa League | , | |
| Jack Frost | frost-001joh | 1904 | 438 ab | Natchez Indians | Cotton States League | , | |
| Frank Frye | 1904 | 4/30-5/14 | Marion Oilworkers/Peoria Distillers | Central League | , | ||
| William Frye | frye--001wil | 1904 | Monroe Hill Citys | Cotton States League | , | ||
| Jesse Frysinger | frysin001jes | 1904 | 5/3-10/1 | Wilmington Peaches | Tri-State League | , | |
| Pearly Fugler | fugler000pea | 1904-07 | Vanderbilt Univ. | College | , | ||
| Fuller | fuller013--- | 1904 | 8/4- | Knoxville | Tennessee-Alabama League | , | |
| Charles Fuller | fuller003cha | 1904 | 5/7-9/28 | Toronto Maple Leafs | Eastern League | , | |
| Fuqua | fuqua-001--- | 1904 | 5/17-5/27+ | Sheffield | Tennessee-Alabama League | , | |
| Fuqua | fuqua-001--- | 1904 | +6/2+ | Bessemer | Tennessee-Alabama League | , | |
| John Furlong | furlon001joh | 1904 | 5/19- | 23 g. | Fargo | Northern League | , |
| Rufus Gaffield | gaffie001--- | 1904 | 4/27-5/2 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Martin Gagin | gagin-001mar | 1904 | Ilion Typewriters | New York State League | , | ||
| Edward Gagnier | gagnie001edw | 1904 | 312 ab | Natchez Indians | Cotton States League | , | |
| Ambrose Gaines | gaines001amb | 1904 | 6/30,+8/3 | Knoxville | Tennessee-Alabama League | , | |
| Joseph Galaski | galask001jos | 1904 | Tacoma Tigers | Pacific Coast League | , | ||
| Joseph Galaski | galask001jos | 1904 | +5/18+ | Bellingham WA | Independent | , | |
| Joseph Galaski | galask001jos | 1904 | 6/12-8/28 | Aberdeen Pippins | Southwest Washington League | , | |
| Eddie Gallagher | gallag001edd | 1904 | 41 g. | Brookhaven | Delta League | , | |
| Eddie Gallagher | gallag001edd | 1904 | 42 g. | San Antonio Bronchos | South Texas League | , | |
| Neil Gamble | gamble001mac | 1904 | +6/22-8/2+ | Decatur | Tennessee-Alabama League | , | |
| Robert Gamble | gamble002rob | 1904 | +6/9-8/2+ | Decatur | Tennessee-Alabama League | , | |
| James Ganier | ganier001jam | 1904 | no g. | Evansville River Rats | Central League | , | |
| James Ganier | ganier001jam | 1904 | Waynesburg PA | Independent | , | ||
| Bob Ganley | ganley002rob | 1904 | Oakland Oaks | Pacific Coast League | , | ||
| Bob Ganley | ganley002rob | 1904 | Johnstown Johnnies | Pennsylvania League | , | ||
| Bill Gannon | gannon002wil | 1904 | 4/23-9/23 | Memphis Egyptians | Southern Association | , | |
| Joe Ganzel | ganzel001jos | 1904 | +6/12-8/10 | Lake Linden Lakers | Copper Country League | , | |
| Joe Ganzel | ganzel001jos | 1904 | +8/21+ | Umpire | Central League | , | |
| John Ganzel | ganzel001joh | 1904 | New York | American League | New York, NY | ||
| Gardner | 1904 | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | |||
| Jim Gardner | gardne001jam | 1904 | 4/30-6/28 | Toronto Maple Leafs | Eastern League | , | |
| Luther Gardner | gardne001lut | 1904 | 5/29-9/29 | Montgomery Senators | Southern Association | , | |
| Garnette | 1904 | Brookhaven | Delta League | , | |||
| Joseph Garrity | garrit001jos | 1904 | 156 ab | Hudson Marines | Hudson River League | , | |
| Jim Garry | garry-001jim | 1904 | 5/6-7/10 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Jim Garry | garry-001jim | 1904 | 7/12-9/3 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| John Garvan | 1904 | Trinity College | College | , | |||
| Leo Garvin | garvin001lee | 1904 | 4/25-9/25 | St. Joseph Saints | Western League | , | |
| Ned Garvin | garvin001vir | 1904 | 23 g. | Brooklyn | National League | Brooklyn, NY | |
| Ned Garvin | garvin001vir | 1904 | 2 g. | New York | American League | New York, NY | |
| Edward Gastmeyer | gastme001edw | 1904 | 57 g. | Hartford Senators | Connecticut State League | , | |
| William Gaston | gaston003wil | 1904 | 90 g. | Clarksdale | Delta League | , | |
| Gates | gates-016--- | 1904 | 8/6-8/8 | Rochester Bronchos | Eastern League | , | |
| Eli Gates | 1904 | Sedalia Goldbugs | Missouri Valley League | , | |||
| Eli Gates | 1904 | Leavenworth Orioles | Missouri Valley League | , | |||
| George Gates | gates-003geo | 1904 | Umpire | South Texas League | , | ||
| Henry Gatewood | gatewo001har | 1904 | 6/10-6/30 | Umpire | Northern League | , | |
| Henry Gatewood | gatewo001har | 1904 | 7/6 | Grand Forks Forkers | Northern League | , | |
| Henry Gatewood | gatewo001har | 1904 | Calumet Aristocrats | Copper Country League | , | ||
| Frank Gatins | gatins001fra | 1904 | 4/29-9/28 | Newark Sailors | Eastern League | , | |
| Gaughan | gaugha002--- | 1904 | 7/30-7/31 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Clyde Gay | gay---001cly | 1904 | 4/29-9/5 | Evansville River Rats | Central League | , | |
| Dale Gear | gear--001dal | 1904 | 4/20-9/5 | Kansas City Blues | American Association | , | |
| Hank Gehring | gehrin001hen | 1904 | 5/21- | 24 g. | Duluth White Sox | Northern League | , |
| Hank Gehring | gehrin001hen | 1904 | +8/16-9/5 | Lake Linden Lakers | Copper Country League | , | |
| Lewis? Gehring | gehrin005--- | 1904 | Montreal-Indep | Independent | , | ||
| Lewis? Gehring | gehrin005--- | 1904 | 9/19-9/28 | Montreal Royals | Eastern League | , | |
| Louis Gehring | gehrin000lew | 1904 | 4/30-5/12 | Dayton Veterans | Central League | , | |
| Phil Geier | geier-001phi | 1904 | 149 g. | Boston | National League | Boston, MA | |
| Fred Geiger | geiger001fre | 1904 | +5/19-6/30+ | Bessemer | Tennessee-Alabama League | , | |
| Fred Geiger | geiger001fre | 1904 | Sheffield | Tennessee-Alabama League | , | ||
| Robert Geiselman | geisel000bob | 1904 | Big Duluth | Independent | , | ||
| Robert Geiselman | geisel000bob | 1904 | +5/30+ | Hibbling MN | Independent | , | |
| Robert Geiselman | geisel000bob | 1904 | +8/1+ | Superior Longshoremen | Northern League | , | |
| John Geiser | 1904 | no g. | Greenville Cotton Pickers | Cotton States League | , | ||
| John Geiser | 1904 | Clarksdale | Delta League | , | |||
| Mike Geisler | geisle000mik | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| John Gele | gele--001joh | 1904 | 60 g. | Canton | Delta League | , | |
| Frank Genins | genins001c-- | 1904 | 4/23-9/25 | New Orleans Pelicans | Southern Association | , | |
| Curtis George | george002cur | 1904 | 5/18-7/12+ | Knoxville | Tennessee-Alabama League | , | |
| Frank Gerard | gerard001fra | 1904 | 50+ g. | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| Ray Gerber | gerber001ray | 1904 | Paterson Intruders | Hudson River League | , | ||
| Albert Gerhardt | gerhar001al- | 1904 | 41 g. | Hattiesburg | Delta League | , | |
| Harry German | german002har | 1904 | 7/30-8/15 | Toledo Mud Hens | American Association | , | |
| Doc Gessler | gessle001har | 1904 | 104 g. | Brooklyn | National League | Brooklyn, NY | |
| Charlie Gettig | gettig002cha | 1904 | 4/29-5/25 | Rochester Bronchos | Eastern League | , | |
| Charlie Gettig | gettig002cha | 1904 | 6/1-7/10 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Charlie Gettig | gettig002cha | 1904 | 7/12-9/17 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Tom Gettinger | gettin001tom | 1904 | 433 ab | Natchez Indians | Cotton States League | , | |
| Jake Gettman | gettma001jac | 1904 | 4/30-7/2 | Buffalo Bisons | Eastern League | , | |
| Jake Gettman | gettma001jac | 1904 | 9/3-9/28 | Buffalo Bisons | Eastern League | , | |
| Peter Getzen | getzen001pet | 1904 | Hudson Marines | Hudson River League | , | ||
| Jacob Geyer | geyer-001jac | 1904 | 6/14- | Alliance OH | Independent | , | |
| John Geyer | geyer-001joh | 1904 | 4/30-9/12 | Grand Rapids Orphans | Central League | , | |
| Ollie Gfroerer | gfroer001oli | 1904 | 436 ab | Pine Bluff Lumbermen | Cotton States League | , | |
| Lewis Gibbs | gibbs-000lew | 1904 | Decatur AL | Independent | , | ||
| Lewis Gibbs | 1904 | 5/22 | Knoxville | Tennessee-Alabama League | , | ||
| Max Gibbs | gibbs-001max | 1904 | 31 g. | San Antonio Bronchos | South Texas League | , | |
| Gibson | 1904 | Peekskill | Hudson River League | , | |||
| Gibson | 1904 | Hudson Marines | Hudson River League | , | |||
| Gibson | 1904 | Salisbury MD | Independent | , | |||
| Gibson | 1904 | Hudson Marines | Hudson River League | , | |||
| Gibson | 1904 | Newburgh Taylor-mades | Hudson River League | , | |||
| Charlie Gibson | gibson006cha | 1904 | 41 g. | Sharon PA | Independent | , | |
| George Gibson | gibson002geo | 1904 | 5/9-9/28 | Montreal Royals | Eastern League | , | |
| Norwood Gibson | gibson001nor | 1904 | 33 g. | Boston | American League | Boston, MA | |
| Ralph Gibson | gibson001ral | 1904 | 5/7-7/10 | Kansas City Blues | American Association | , | |
| Edward Giencke | 1904 | Milw.-West Park | Semi-professional | , | |||
| Al Gifford | giffor001al- | 1904 | 4/29-7/2+ | Umpire | Eastern League | , | |
| Al Gifford | giffor001al- | 1904 | 7/18 | Chattanooga | Tennessee-Alabama League | , | |
| Al Gifford | giffor001al- | 1904 | Umpire | Cotton States League | , | ||
| Billy Gilbert | gilber002wil | 1904 | 146 g. | New York | National League | New York, NY | |
| Gordon Gilbert | gilber001gor | 1904 | 57 g. | Columbia | Tennessee-Alabama League | , | |
| Jack Gilbert | gilber005joh | 1904 | 4/23-9/17 | Little Rock Travelers | Southern Association | , | |
| Jack Gilbert | gilber005joh | 1904 | Pittsburgh | National League | Pittsburgh, PA | ||
| Rufus Gilbert | gilber001ruf | 1904 | 5/24 | Superior Longshoremen | Northern League | , | |
| Rufus Gilbert | gilber001ruf | 1904 | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | ||
| William Gilchrist | gilchr001w-- | 1904 | Sauk Centre | Independent | , | ||
| Bob Gilks | gilks-001rob | 1904 | 4/24-9/22 | Shreveport Pirates | Southern Association | , | |
| Roy Gill | gill--002roy | 1904 | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | ||
| Warren Gill | gill--001war | 1904 | 62 g. | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |
| John Gilland | gillan000des | 1904 | +4/8+ | U. South Carolina | College | , | |
| Tommy Gilleran | giller001tho | 1904 | Newburgh Taylor-mades | Hudson River League | , | ||
| Gillespie | 1904 | 8 g. | Alliance OH | Independent | , | ||
| Gilliam | gillia004--- | 1904 | Shreveport Pirates | Southern Association | , | ||
| Eddie Gilligan | gillig001edw | 1904 | 5/11- | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| Eddie Gilligan | gillig001edw | 1904 | 8/1-9/12 | Grand Rapids Orphans | Central League | , | |
| Thomas Gilligan | gillig001tho | 1904 | +8/19+ | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |
| Thomas Gilligan | gillig001tho | 1904 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | ||
| Thomas Gilligan | gillig002tho | 1904 | 44 g. | Grand Rapids Orphans | Central League | , | |
| George Gillpatrick | gillpa001geo | 1904 | +4/17-9/25+ | KC-Athletic | Independent | , | |
| Gilmore | gilmor012--- | 1904 | +8/17-9/5 | Burlington River Rats | Iowa League | , | |
| Gilpatrick | 1904 | +4/29-5/27+ | Wash. Agri. Col. | College | , | ||
| Gilpatrick | 1904 | +8/28+ | Spok.-Rapp&Lloyd | Independent | , | ||
| Will Gilreath | gilrea002wil | 1904 | +5/7+ | Tyler TX | Independent | , | |
| Will Gilreath | gilrea002wil | 1904 | 6/9-7/4 | Corsicana Oil Citys | Texas League | , | |
| Thomas Gilroy | gilroy001tho | 1904 | 4/30-9/17 | Fall River Indians | New England League | , | |
| Frank Gimlin | gimlin001joh | 1904 | 128 g. | Salt Lake City Elders | Pacific National League | , | |
| Billy Ging | ging--001bil | 1904 | 5/6-8/8 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Alexander Girard | girard000ale | 1904 | 5/8-9/4 | Hoquiam Perfect Gentlemen | Southwest Washington League | , | |
| Fred Glade | glade-001fre | 1904 | 35 g. | St. Louis | American League | St. Louis, MO | |
| Percy Glass | 1904 | 8/11-9/5 | Lake Linden Lakers | Copper Country League | , | ||
| William Glassburner | glassb001wil | 1904 | 83 g. | Niles OH | Independent | , | |
| William Glassburner | glassb001wil | 1904 | +7/27+ | Youngstown OH | Independent | , | |
| William Glassburner | glassb001wil | 1904 | +9/20+ | Niles OH | Independent | , | |
| Adam Glatz | glatz-001--- | 1904 | no g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| Eddie Glavin | glavin001edw | 1904 | 5/6-9/17 | Binghamton Bingoes | New York State League | , | |
| Gleason | gleaso024--- | 1904 | 7/10-9/4 | Aberdeen Pippins | Southwest Washington League | , | |
| Frank Gleason | gleaso000fra | 1904 | Helena MT | Independent | , | ||
| Harry Gleason | gleaso001har | 1904 | 46 g. | St. Louis | American League | St. Louis, MO | |
| Kid Gleason | gleaso002wil | 1904 | 153 g. | Philadelphia | National League | Philadelphia, PA | |
| William Gleason | gleaso004wil | 1904 | Chic.- | Chicago City League | , | ||
| William Gleason | gleaso004wil | 1904 | 6/3-7/23 | Marshalltown Grays | Iowa League | , | |
| Bob Glenalvin | glenal001bob | 1904 | 5/14-5/24 | Binghamton Bingoes | New York State League | , | |
| Martin Glendon | glendo001mar | 1904 | 4/23-9/15 | Columbus Senators | American Association | , | |
| Ed Glenn | glenn-001edw | 1904 | 15 g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| Glzier | 1904 | 5/7-5/8 | Oskaloosa Quakers | Iowa League | , | ||
| Ed Gnadinger | gnadin001edw | 1904 | 431 ab | Baton Rouge Red Sticks | Cotton States League | , | |
| John Gochnaur | gochna001joh | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| John Gochnaur | gochna001joh | 1904 | 5/11-8/13+ | Altoona Mountaineers | Tri-State League | , | |
| John Godwin | godwin001joh | 1904 | 119 g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| Edmund Goes | goes--001edw | 1904 | Military Service | , | |||
| Henry Goff | 1904 | Winnipeg Maroons | Northern League | , | |||
| Ed Gogan | gogan-001ed- | 1904 | 63 ab | Natchez Indians | Cotton States League | , | |
| Eugene Gokey | gokey-001eug | 1904 | 4/30-8/23 | Nashua | New England League | , | |
| Golden | 1904 | 5/7-5/13 | Umpire | Iowa League | , | ||
| John Golden | golden002joh | 1904 | New Haven Blues | Connecticut State League | , | ||
| Tom Golden | golden001tho | 1904 | Reading PA | Independent | , | ||
| Walt Goldsby | goldsb001wal | 1904 | Umpire | South Atlantic League | , | ||
| Gompher | gomphe000--- | 1904 | 6/4 | Toledo Mud Hens | American Association | , | |
| Johnny Gonding | gondin001joh | 1904 | 4/24-9/25 | Omaha Rangers | Western League | , | |
| Valentin Gonzalez | 1904 | Habana | Cuba-Negro | , | |||
| Valentin Gonzalez | 1904 | Habana | Cuban Winter League | , | |||
| Valentin Gonzalez | 1904 | Punzo | Cuban League | , | |||
| Gene Good | good--001eug | 1904 | 8/8-8/9 | New Bedford Whalers | New England League | , | |
| Wilbur Good | good--002wil | 1904 | College | , | |||
| Wilbur Good | good--002wil | 1904 | 6/8-6/23 | Johnstown PA | Independent | , | |
| Ralph? Goodearl | goodea001r-- | 1904 | 32 g. | Iola Gasbags | Missouri Valley League | , | |
| Ralph? Goodearl | goodea001r-- | 1904 | Leavenworth Orioles | Missouri Valley League | , | ||
| Doc Goodell | goodal001doc | 1904 | no g. | Pittsburg Coal Diggers | Missouri Valley League | , | |
| John Goodrich | goodri001joh | 1904 | +5/12+ | Mt. Vernon OH | Independent | , | |
| Art Goodwin | goodwi001art | 1904 | 4/29-9/23 | Memphis Egyptians | Southern Association | , | |
| Clyde Goodwin | goodwi001cly | 1904 | 4/30-6/8 | Evansville River Rats | Central League | , | |
| Clyde Goodwin | goodwi001cly | 1904 | 27 g. | Memphis Egyptians | Southern Association | , | |
| Clyde Goodwin | goodwi001cly | 1904 | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | ||
| Brooks Gordon | gordon001bro | 1904 | 105 g. | Galveston Sand Crabs | South Texas League | , | |
| Eugene Gorman | gorman000eug | 1904 | Atlantic City NJ | Independent | , | ||
| Gene Gormley | 1904 | 5/24-5/25 | Dayton Veterans | Central League | , | ||
| Ly Gorton | gorton001lym | 1904 | 111 g. | San Francisco Seals | Pacific Coast League | , | |
| Roger Gorton | gorton001rog | 1904 | Kalamazoo Col | College | , | ||
| Claude Gouzzie | gouzzi001cla | 1904 | 88 g. | Niles OH | Independent | , | |
| Claude Gouzzie | gouzzi001cla | 1904 | Sharon PA | Independent | , | ||
| W. M. Gove | gove--000doc | 1904 | 5 g. | Canton OH | Independent | , | |
| Graa | 1904 | 2 g. | Decatur | Tennessee-Alabama League | , | ||
| Mike Grady | grady-002mic | 1904 | 101 g. | St. Louis | National League | St. Louis, MO | |
| William Graffius | graffi001wil | 1904 | 4/23-9/24 | Shreveport Pirates | Southern Association | , | |
| Vincent Gragion | gragio000vin | 1904 | +9/5+ | St. Mary’s | Rochester Catholic | , | |
| Charlie Graham | graham002cha | 1904 | Tacoma Tigers | Pacific Coast League | , | ||
| Earl Graham | graham001ear | 1904 | 76 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| Harry Graham | graham002har | 1904 | +5/16+ | Astoria-Commercial | Independent | , | |
| Moonlight Graham | graham001arc | 1904 | U. of Maryland | College | , | ||
| Moonlight Graham | graham001arc | 1904 | 4/30-9/17 | Manchester | New England League | , | |
| Oscar Graham | graham001osc | 1904 | 79 g. | Oakland Oaks | Pacific Coast League | , | |
| Peaches Graham | graham002geo | 1904 | 4/24-9/25 | Colorado Springs Millionaires | Western League | , | |
| Lee Gramley | gramle001lee | 1904 | +8/10+ | Sedalia Goldbugs | Missouri Valley League | , | |
| Angus Grant | grant-001ang | 1904 | 4/28-9/11 | South Bend Greens | Central League | , | |
| Benjamin Grant | grant-001ben | 1904 | 94 g. | Springfield Midgets | Missouri Valley League | , | |
| Benjamin Grant | grant-001ben | 1904 | Joplin Miners | Missouri Valley League | , | ||
| Eddie Grant | grant-001edw | 1904 | +7/14+ | St. Albans | Northern New York League | , | |
| George Grant | grant-003geo | 1904 | 4/30-9/17 | Lowell Tigers | New England League | , | |
| Arthur Granville | granvi001art | 1904 | 5/18-9/24 | Little Rock Travelers | Southern Association | , | |
| Graves | 1904 | Duluth White Sox | Northern League | , | |||
| Dr. Phil? Graves | graves001--- | 1904 | 8/2-8/25 | Sioux City Soos | Western League | , | |
| George Graves | graves001geo | 1904 | 94 g. | Fort Scott Giants | Missouri Valley League | , | |
| Billy Gray | gray--003bil | 1904 | 5/5-6/17 | Camden | Tri-State League | , | |
| Billy Gray | gray--003bil | 1904 | 7/1-8/4 | Wilmington Peaches | Tri-State League | , | |
| Cecil Gray | gray--001cec | 1904 | 7/27-9/11 | Terre Haute Hottentots | Central League | , | |
| Chummy Gray | gray--001chu | 1904 | 7/4-7/22 | Utica Pent-Ups | New York State League | , | |
| Chummy Gray | gray--001chu | 1904 | 7/26-9/16 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Dolly Gray | gray--003wil | 1904 | 55 g. | Los Angeles Angels | Pacific Coast League | , | |
| Leonard Gray | gray--001leo | 1904 | 5/7-8/18+ | Keokuk Indians | Iowa League | , | |
| William Gray | gray--001w-- | 1904 | 119 g. | Joplin Miners | Missouri Valley League | , | |
| Danny Green | green-001edw | 1904 | 147 g. | Chicago | American League | Chicago, IL | |
| Frank Green | green-002fra | 1904 | 5/23- | 39 g. | Superior Longshoremen | Northern League | , |
| Frank Green | green-002fra | 1904 | Acton | Independent | , | ||
| Johnny Green | green-001joh | 1904 | +6/10-9/5 | Keokuk Indians | Iowa League | , | |
| Ernest Greene | greene001ern | 1904 | 6/29-9/28 | Buffalo Bisons | Eastern League | , | |
| Paddy Greene | greene001pat | 1904 | 5/6-9/10 | Albany Senators | New York State League | , | |
| Teddy Greene | greene001ted | 1904 | 5/7-9/5 | Marshalltown Grays | Iowa League | , | |
| Greer | greer-001--- | 1904 | +6/16+ | Bessemer | Tennessee-Alabama League | , | |
| Greer | greer-001--- | 1904 | +6/28+ | Columbia | Tennessee-Alabama League | , | |
| Greer | greer-001--- | 1904 | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | ||
| Hunter Gregg | gregg-001hun | 1904 | 5/2-7/2 | Galveston Sand Crabs | South Texas League | , | |
| Gregory | 1904 | Keokuk Indians | Iowa League | , | |||
| Fred Gregory | gregor000fre | 1904 | 4/29-5/6 | Roseburg Shamrocks | Oregon State League | , | |
| Fred Gregory | gregor000fre | 1904 | 5/8-5/15 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Fred Gregory | gregor000fre | 1904 | 5/18-7/4 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Fred Gregory | gregor000fre | 1904 | 7/24-9/5 | Olympia Senators | Southwest Washington League | , | |
| Ed Gremminger | gremmi001lor | 1904 | - 7/30 | 83 g. | Detroit | American League | Detroit, MI |
| Ed Gremminger | gremmi001lor | 1904 | 8/4-9/20 | Minneapolis Millers | American Association | , | |
| Gribbroeck | gribbr001--- | 1904 | Roch.-Naveys | Rochester Indoor League | , | ||
| Mathias Griebler | griebl000mat | 1904 | +5/23 | Lisbon ND | Independent | , | |
| Mathias Griebler | griebl000mat | 1904 | 6/24 | Devil’s Lake ND | Independent | , | |
| Mathias Griebler | griebl000mat | 1904 | Fargo | Northern League | , | ||
| Griffin | 1904 | Peekskill | Hudson River League | , | |||
| Edward Griffin | griffi001edw | 1904 | Saugerties | Hudson River League | , | ||
| Jack Griffin | griffi003j-- | 1904 | 6/23-7/2 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Sandy Griffin | griffi001san | 1904 | 5/6-9/18 | Syracuse Stars | New York State League | , | |
| Steve Griffin | griffi001ste | 1904 | Baltimore Orioles | Eastern League | , | ||
| Henry Griffith | griffi004fra | 1904 | Coatesville | Pennsylvania League | , | ||
| Jack Grim | grim--001joh | 1904 | 4/26-7/? | Columbia Skyscrapers | South Atlantic League | , | |
| Jack Grim | grim--001joh | 1904 | +7/2-9/9 | Umpire | South Atlantic League | , | |
| John Grim | grim--002joh | 1904 | 5/20-5/29 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| John Grim | grim--002joh | 1904 | 5/30-7/18 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| John Grim | grim--002joh | 1904 | 7/28-8/8 | Umpire | American Association | , | |
| Grimes | grimes016--- | 1904 | 11 g. | Columbia Skyscrapers | South Atlantic League | , | |
| Grimes | grimes016--- | 1904 | Augusta Tourists | South Atlantic League | , | ||
| Paul Grimes | grimes001pau | 1904 | Ludington MI | Independent | , | ||
| Huber Grimm | grimm-000hub | 1904 | 5/29-9/4 | Centralia Midgets | Southwest Washington League | , | |
| Myron Grimshaw | grimsh001myr | 1904 | 4/30-9/28 | Buffalo Bisons | Eastern League | , | |
| E. M.? Grindle | 1904 | 5/13-5/16 | Dayton Veterans | Central League | , | ||
| E. M.? Grindle | 1904 | 6/9 | Evansville River Rats | Central League | , | ||
| William Groeschow | groesc001wil | 1904 | 5/7-9/11 | Terre Haute Hottentots | Central League | , | |
| Grogan | 1904 | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |||
| John Grogan | grogan004joh | 1904 | +6/14-8/17+ | Burlington River Rats | Iowa League | , | |
| C. Groh | 1904 | +6/6+ | Addison NY | Independent | , | ||
| Lewis Groh | groh--001lew | 1904 | +6/6+ | Addison NY | Independent | , | |
| Lewis Groh | groh--001lew | 1904 | 6/29-9/9 | Addison White Sox | Southern Tier League | , | |
| Robert Groom | groom-001rob | 1904 | 37 g. | Fort Scott Giants | Missouri Valley League | , | |
| Ernie Groth | groth-001ern | 1904 | Decatur Commodores | Illinois-Indiana-Iowa League | , | ||
| Ernie Groth | groth-001ern | 1904 | Pt. WashingtonWI | Lake Shore League | , | ||
| Ernie Groth | groth-001ern | 1904 | 9/6-10/7 | Chicago | National League | Chicago, IL | |
| W. M. Grove | grove-000wm- | 1904 | 7/9-7/15 | Rochester Bronchos | Eastern League | , | |
| George Groves | groves001geo | 1904 | 5/16 | Anniston | Tennessee-Alabama League | , | |
| Herbert Grubb | grubb-001her | 1904 | 474 ab | Pine Bluff Lumbermen | Cotton States League | , | |
| Frank Grubbs | grubbs002fra | 1904 | 5/6 | Terre Haute Hottentots | Central League | , | |
| Frank Grubbs | grubbs002fra | 1904 | 5/13-6/17 | Fort Wayne Railroaders | Central League | , | |
| Louis Gruebner | gruebn001lou | 1904 | 110 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| Whitey Guese | guese-001the | 1904 | 4/23-9/13 | Little Rock Travelers | Southern Association | , | |
| Thomas Guiheen | guihee001tho | 1904 | 4/30- | New Bedford Whalers | New England League | , | |
| Thomas Guiheen | guihee001tho | 1904 | -9/19 | Fall River Indians | New England League | , | |
| Frank Gum | gum---002fra | 1904 | 6 g. | Springfield Midgets | Missouri Valley League | , | |
| Frank Gum | gum---002fra | 1904 | Chester | Pennsylvania League | , | ||
| Gunion | gunion000--- | 1904 | 8/24-8/27 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Cecil Gunter | gunter001c-- | 1904 | 101 g. | Columbia Skyscrapers | South Atlantic League | , | |
| Frank Gunther | gunthe001fra | 1904 | 475 ab | Newburgh Taylor-mades | Hudson River League | , | |
| J. Gustropski/Go | 1904 | Norwich Reds | Connecticut State League | , | |||
| Wilfred Gutierrez | guitte001wil | 1904 | 53 g. | Canton | Delta League | , | |
| Isaac Guyn | guyn--001how | 1904 | U. Kentucky | College | , | ||
| Howard Gwynn | 1904 | 16 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | ||
| Howard Gwynn | 1904 | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |||
| Howard Gwynn | 1904 | 42 g. | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | ||
| Frank Gygli | gygli-001fra | 1904 | 8/1- | 10 g. | Warren OH | Independent | , |
| Bert Haas | haas--001ber | 1904 | 31 g. | Warren OH | Independent | , | |
| Bert Haas | haas--001ber | 1904 | 7/16-7/27 | Grand Rapids Orphans | Central League | , | |
| Bert Haas | haas--001ber | 1904 | 7/28-7/30 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Bert Haas | haas--001ber | 1904 | 7/31-9/9 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Carl Haas | 1904 | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |||
| Clarence Haas | 1904 | Cairo Champions | Kentucky-Illinois-Tennessee League | , | |||
| Jim Hackett | hacket001jam | 1904 | 5/24-5/29 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Jim Hackett | hacket001jam | 1904 | 6/1-6/27 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Jim Hackett | hacket001jam | 1904 | 69 g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| Tom Hackett | hacket001tho | 1904 | 5/7-9/5 | Keokuk Indians | Iowa League | , | |
| Hardy Hadden | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |||
| Hubert Hadley | hadley001hub | 1904 | 114 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| Frank Hafford | haffor001fra | 1904 | 5/11-6/8 | Williamsport Millionaires | Tri-State League | , | |
| Frank Hafford | haffor001fra | 1904 | +7/11+ | New Bedford Whalers | New England League | , | |
| Raymond Hagan | hagan-001ray | 1904 | Coatesville PA | Independent | , | ||
| Raymond Hagan | hagan-001ray | 1904 | 8/- | Elmira | Southern Tier League | , | |
| Kurt Hageman | 1904 | Wampum PA | Independent | , | |||
| Alf Hagerman | hagerm001alf | 1904 | 34 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Peter Hagerty | hagert001pet | 1904 | 34 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Peter Hagerty | hagert001pet | 1904 | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | ||
| Ed Hahn | hahn--003wil | 1904 | Vicksburg Hill Billies | Cotton States League | , | ||
| Frank Hahn | hahn--017--- | 1904 | 7/11-7/22 | Elmira | Southern Tier League | , | |
| Frank Hahn | hahn--017--- | 1904 | 7/27-8/19 | Hornellsville Maple Cities | Southern Tier League | , | |
| Noodles Hahn | hahn--001fra | 1904 | Cincinnati | National League | Cincinnati, OH | ||
| Phil Hahn | hahn--002phi | 1904 | Charleston WV | Independent | , | ||
| Louis Haidt | haidt-001lou | 1904 | Louisville Colonels | American Association | , | ||
| Louis Haidt | haidt-001lou | 1904 | 4/27-6/28 | Fort Worth Panthers | Texas League | , | |
| Benjamin Halbert | halber001f-- | 1904 | 5/8-9/4 | Hoquiam Perfect Gentlemen | Southwest Washington League | , | |
| Jess Hale | hale--001jes | 1904 | 5/6-5/20 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Jess Hale | hale--001jes | 1904 | Springfield Ponies | Connecticut State League | , | ||
| Ray Hale | hale--001ray | 1904 | 4/30-5/21 | Memphis Egyptians | Southern Association | , | |
| Ray Hale | hale--001ray | 1904 | 6/6-9/23 | Montgomery Senators | Southern Association | , | |
| Hall | hall--004rob | 1904 | 8/4-8/27 | Wilmington Peaches | Tri-State League | , | |
| Bob Hall | hall--004rob | 1904 | 4/18- | 46 g. | Philadelphia | National League | Philadelphia, PA |
| Bob Hall | hall--004rob | 1904 | 8/4-9/23 | Wilmington Peaches | Tri-State League | , | |
| Charley Hall | hall--004cha | 1904 | 62 g. | Seattle Siwashes | Pacific Coast League | , | |
| Louis Hall | hall--001lou | 1904 | +5/17- | Cairo Champions | Kentucky-Illinois-Tennessee League | , | |
| Louis Hall | hall--001lou | 1904 | -9/+ | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| Louis Hall | hall--001lou | 1904 | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | ||
| Louis Hall | hall--001lou | 1904 | +7/20+ | 4 g. | Sheffield | Tennessee-Alabama League | , |
| Russ Hall | hall--011rob | 1904 | Seattle Siwashes | Pacific Coast League | , | ||
| Rusty Hall | hall--001war | 1904 | 46 g. | Los Angeles Angels | Pacific Coast League | , | |
| John Halla | halla-001joh | 1904 | 68 g. | Pittsburg Coal Diggers | Missouri Valley League | , | |
| Jocko Halligan | hallig001joc | 1904 | Jersey City Skeeters | Eastern League | , | ||
| Bill Hallman | hallma002wil | 1904 | 4/24-9/25 | Denver Grizzlies | Western League | , | |
| Bill Hallman | hallma001wil | 1904 | 4/29-9/19 | Louisville Colonels | American Association | , | |
| Thomas Hambacher | 1904 | Utica Pent-Ups | New York State League | , | |||
| Thomas Hambacher | 1904 | PA Indep | Independent | , | |||
| Charlie Hamburg | hambur003cha | 1904 | 42 g. | Hattiesburg | Delta League | , | |
| Charlie Hamburg | hambur003cha | 1904 | 23 g. | Columbia Skyscrapers | South Atlantic League | , | |
| Hamilton | 1904 | 9/15 | Little Rock Travelers | Southern Association | , | ||
| Argus Hamilton | hamilt001arg | 1904 | 4/29-5/17 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Argus Hamilton | hamilt001arg | 1904 | 5/27-6/22 | Grand Rapids Orphans | Central League | , | |
| Argus Hamilton | hamilt001arg | 1904 | 7/4-8/1 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Argus Hamilton | hamilt001arg | 1904 | 8/7-8/14 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Argus Hamilton | hamilt001arg | 1904 | 8/11 | Dallas Giants | Texas League | , | |
| Billy Hamilton | hamilt006wil | 1904 | 4/30-9/17 | Haverhill Hustlers | New England League | , | |
| Lee Hamilton | 1904 | Eufaula AL | Independent | , | |||
| Sandy Hamilton | hamilt001ale | 1904 | 6/29- | Weir City KS | Independent | , | |
| Hammond | hammon014--- | 1904 | Oakland | California State League | , | ||
| Eddie Hammond | hammon001edw | 1904 | 91 g. | Boise Fruit Pickers | Pacific National League | , | |
| Harry Hammond | hammon001har | 1904 | 4/29-5/17 | Dayton Veterans | Central League | , | |
| Harry Hammond | hammon001har | 1904 | 8/20-9/11 | Dayton Veterans | Central League | , | |
| Jim Haney | haney-003jam | 1904 | 44 g. | Fort Scott Giants | Missouri Valley League | , | |
| Charles Hanford | 1904 | +5/25+ | Tren.-YMCA | Independent | , | ||
| Chip Hanford | hanfor002cha | 1904 | 68 g. | Youngstown OH | Independent | , | |
| Jack Hankey | hankey001joh | 1904 | 4/20-4/21 | Milwaukee Brewers | American Association | , | |
| Jack Hankey | hankey001joh | 1904 | 82 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Arthur Hanks | hanks-001art | 1904 | 4/30-5/2 | Fall River Indians | New England League | , | |
| Arthur Hanks | hanks-001art | 1904 | 5/13-5/17 | Camden | Tri-State League | , | |
| Arthur Hanks | hanks-001art | 1904 | Linder PA | Independent | , | ||
| Arthur Hanks | hanks-001art | 1904 | 8/30 | Lebanon | Tri-State League | , | |
| Arthur Hanks | hanks-001art | 1904 | Linder PA | Independent | , | ||
| Arthur Hanks | hanks-001art | 1904 | Lebanon | Tri-State League | , | ||
| George Hanley | hanley002geo | 1904 | 4/21-7/21 | Birmingham Barons | Southern Association | , | |
| George Hanley | hanley002geo | 1904 | 7/25-9/24 | Shreveport Pirates | Southern Association | , | |
| William? Hanley | 1904 | Hudson Marines | Hudson River League | , | |||
| Hanlon | 1904 | Greenville Cotton Pickers | Cotton States League | , | |||
| Hanlon | 1904 | 7/23-8/31 | Wheeling Stogies | Central League | , | ||
| Bill Hanlon | hanlon001wil | 1904 | 5/8-5/29 | Olympia Senators | Southwest Washington League | , | |
| Edward Hanlon | 1904-07 | , | |||||
| Larry Hannafin | hannaf001law | 1904 | 44 g. | New Haven Blues | Connecticut State League | , | |
| Jack Hannifin | hannif002joh | 1904 | 103 g. | Springfield Ponies | Connecticut State League | , | |
| Jack Hannifin | hannif002joh | 1904 | Norwich Reds | Connecticut State League | , | ||
| Pat Hannivan | hanniv001pat | 1904 | 48 g. | Tacoma Tigers | Pacific Coast League | , | |
| Pat Hannivan | hanniv001pat | 1904 | 50 g. | Salt Lake City Elders | Pacific National League | , | |
| Pat Hannivan | hanniv001pat | 1904 | 8/4-8/15 | Toledo Mud Hens | American Association | , | |
| Pat Hannivan | hanniv001pat | 1904 | 8/27-9/16 | Binghamton Bingoes | New York State League | , | |
| Billy Hanrahan | hanrah001wil | 1904 | 5/19-8/4+ | 52 g. | Grand Forks Forkers | Northern League | , |
| Billy Hanrahan | hanrah001wil | 1904 | +8/18+ | Portage Lake | Copper Country League | , | |
| Harry Hanrahan | hanrah000har | 1904 | +5/27+ | GF-Cosmos | Amateur | , | |
| Peter Hansen | hansen001pet | 1904 | +5/23+ | Lisbon ND | Independent | , | |
| Peter Hansen | hansen001pet | 1904 | 15 g. | Fargo | Northern League | , | |
| Hansen/Hanson | hansen007--- | 1904 | 5/8-5/22 | Aberdeen Pippins | Southwest Washington League | , | |
| Hanson | hanson033--- | 1904 | +7/8-7/28+ | Burlington River Rats | Iowa League | , | |
| George Hanson | hanson001geo | 1904 | 9 g. | San Francisco Seals | Pacific Coast League | , | |
| George Hanson | hanson001geo | 1904 | 105 g. | Boise Fruit Pickers | Pacific National League | , | |
| H. C. Hanson | hanson001h-- | 1904 | 6 g. | Leavenworth Orioles | Missouri Valley League | , | |
| Oren Hanson | hanson001ore | 1904 | Lisbon ND | Northern League | , | ||
| Oren Hanson | hanson001ore | 1904 | 7/22-8/9 | Fargo | Northern League | , | |
| Charles Harbin | harbin002cha | 1904 | 5/16-6/30+ | Bessemer | Tennessee-Alabama League | , | |
| Scott Hardesty | hardes002sco | 1904 | 4/30-5/14 | Manchester | New England League | , | |
| Scott Hardesty | hardes002sco | 1904 | +8/5-8/25+ | Umpire | New York State League | , | |
| Frank Harding | hardin002fra | 1904 | Forsyth MT | Independent | , | ||
| Hardy | hardy-018--- | 1904 | 9/17 | Columbus Senators | American Association | , | |
| Alex Hardy | hardy-001dav | 1904 | 4/21-9/10 | Atlanta Crackers | Southern Association | , | |
| Ellis Hardy | hardy-001ell | 1904 | 58 g. | San Antonio Bronchos | South Texas League | , | |
| Felix Hardy | hardy-001ell | 1904 | 5/26-6/8 | Atlanta Crackers | Southern Association | , | |
| Harry Hardy | hardy-001har | 1904 | 24 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| Jack Hardy | hardy-001joh | 1904 | 5/21-9/11 | Fort Wayne Railroaders | Central League | , | |
| Henry Hargis | hargis001hen | 1904 | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | ||
| Dennis Hargrove | hargro005--- | 1904 | Bankers League | Independent | , | ||
| Dennis Hargrove | hargro005--- | 1904 | 11 g. | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |
| Dennis Hargrove | hargro005--- | 1904 | Davenport River Rats | Illinois-Indiana-Iowa League | , | ||
| Harley | harley004--- | 1904 | 12 g. | Clarksdale | Delta League | , | |
| Dick Harley | harley001ric | 1904 | 4/29-9/23 | Toronto Maple Leafs | Eastern League | , | |
| Dick Harley | harley001hen | 1904 | 5/8-9/18 | Syracuse Stars | New York State League | , | |
| Hy Harley | harley000hy- | 1904 | 15 g. | Fort Scott Giants | Missouri Valley League | , | |
| William Harley | harley001wil | 1904 | 34+ g. | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| Con Harlow | harlow001con | 1904 | 93 ab | Natchez Indians | Cotton States League | , | |
| Con Harlow | harlow001con | 1904 | Umpire | Delta League | , | ||
| Henry/Harry Harmon | 1904 | 5/8-5/29 | Aberdeen Pippins | Southwest Washington League | , | ||
| Ira Harmon | harmon001ira | 1904 | 5/8-7/24 | Centralia Midgets | Southwest Washington League | , | |
| Ira Harmon | harmon001ira | 1904 | +8/3-9/11+ | 13 g. | Spokane Indians | Pacific National League | , |
| Walter Harmon | harmon001wal | 1904 | 128 ab | Hudson Marines | Hudson River League | , | |
| Walter Harmon | harmon001wal | 1904 | 6/12 | Utica Pent-Ups | New York State League | , | |
| Walter Harmon | harmon001wal | 1904 | Hudson Marines | Hudson River League | , | ||
| Nick Harnish | harnis001nic | 1904 | 77 g. | Macon Highlanders | South Atlantic League | , | |
| Jack Harper | harper003cha | 1904 | 35 g. | Cincinnati | National League | Cincinnati, OH | |
| Bernard Harrigan | 1904 | Scammon KS | Independent | , | |||
| Harrington | harrin010--- | 1904 | 9/2 | Haverhill Hustlers | New England League | , | |
| Guy Harrington | harrin001guy | 1904 | 91 g. | Fort Scott Giants | Missouri Valley League | , | |
| Joe Harrington | harrin001joe | 1904 | Norwich Reds | Connecticut State League | , | ||
| Joe Harrington | harrin001joe | 1904 | 7/27-9/19 | New Bedford Whalers | New England League | , | |
| John Harrington | harrin001joh | 1904 | 5/10-6/2 | Ilion Typewriters | New York State League | , | |
| Ewing Harris | harris001ewi | 1904 | 32+ g. | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |
| Hank Harris | harris001hen | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| Henry Harris | harris003hen | 1904 | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | ||
| J. Harris | harris042--- | 1904 | 9/15-9/28 | Providence Grays | Eastern League | , | |
| Joe Harris | harris007jos | 1904 | 5/3-9/14 | Fall River Indians | New England League | , | |
| John Harris | harris001joh | 1904 | 6/16+ | Ardmore IT | Independent | , | |
| John Harris | harris001joh | 1904 | 8/5 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| John Harris | harris001joh | 1904 | Dallas Giants | Texas League | , | ||
| Joseph Harris | harris002jos | 1904 | +8/26+ | Lake Linden Lakers | Copper Country League | , | |
| John Harrison | harris012joh | 1904 | 7/8 | Manchester | New England League | , | |
| Leo Harrison | harris005leo | 1904 | 465 ab | Saugerties | Hudson River League | , | |
| Harry Harrod | harrod001har | 1904 | 4/28-5/11 | South Bend Greens | Central League | , | |
| Bill Hart | hart--004wil | 1904 | 4/20-9/20 | Umpire | American Association | , | |
| Bill Hart | hart--004wil | 1904 | 9/20 | Kansas City Blues | American Association | , | |
| Eugene Hart | hart--001eug | 1904 | 4/30- | Lawrence Colts | New England League | , | |
| Eugene Hart | hart--001eug | 1904 | -6/14 | Lowell Tigers | New England League | , | |
| Harry Hart | hart--002har | 1904 | Umpire | Central League | , | ||
| Jimmy Hart | hart--003jam | 1904 | 4/20-9/9 | Louisville Colonels | American Association | , | |
| Jimmy Hart | hart--003jam | 1904 | Calumet Aristocrats | Copper Country League | , | ||
| Thomas Hart | hart--002tho | 1904 | 4/29-5/11 | Dayton Veterans | Central League | , | |
| Thomas Hart | hart--002tho | 1904 | 7/3-9/10 | Fort Wayne Railroaders | Central League | , | |
| Warren Hart | 1904 | no g. | Galveston Sand Crabs | South Texas League | , | ||
| Chick Hartley | hartle001wal | 1904 | 5/1-7/18 | Harrisburg Senators | Tri-State League | , | |
| Chick Hartley | hartle001wal | 1904 | 8/8-9/10 | Wilmington Peaches | Tri-State League | , | |
| Fred Hartman | hartma003fre | 1904 | 5/6-9/27 | Montreal Royals | Eastern League | , | |
| William Hartman | hartma001wil | 1904 | 4/24-9/25 | St. Joseph Saints | Western League | , | |
| William Hartman | hartma002wil | 1904 | 6/10-6/18 | Wilmington Peaches | Tri-State League | , | |
| Roy Hartzell | hartze001roy | 1904 | 4/24-9/25 | Denver Grizzlies | Western League | , | |
| Harvey | harvey011--- | 1904 | 4/27-5/27 | Des Moines Prohibitionists | Western League | , | |
| James Harvey | harvey001jam | 1904 | 31+ g. | Cairo Champions | Kentucky-Illinois-Tennessee League | , | |
| William Harvey | 1904 | Topeka Saints | Missouri Valley League | , | |||
| Jack Haskell | haskel001jac | 1904 | 4/30-8/15+ | Umpire | Eastern League | , | |
| William Haslem | haslem001wil | 1904 | 5/6-9/15 | Syracuse Stars | New York State League | , | |
| Hassett | 1904 | Umpire | Hudson River League | , | |||
| Christy Hassett | hasset001chr | 1904 | 5/6-6/19+ | Umpire | New York State League | , | |
| Christy Hassett | hasset001chr | 1904 | 7/4-9/9 | Umpire | Southern Tier League | , | |
| James Hassett | 1904 | , | |||||
| William Hassett | 1904 | 5/11 | Albany Senators | New York State League | , | ||
| Edward Hasterlik | haster000ed- | 1904 | GrFa-Mavericks | Independent | , | ||
| Charlie Hastings | hastin002cha | 1904 | 6/9-9/16 | Concord Marines | New England League | , | |
| Ira Hastings | hastin001ira | 1904 | 5/15-7/3 | Olympia Senators | Southwest Washington League | , | |
| Ira Hastings | hastin001ira | 1904 | +8/10+ | Portland Browns | Pacific Coast League | , | |
| Hauer | hauer-000--- | 1904 | 3 g. | Keokuk Indians | Iowa League | , | |
| Bill Hausen | hausen001hom | 1904 | 128 g. | Salt Lake City Elders | Pacific National League | , | |
| Emil Hauser | hauser001emi | 1904 | +7/3-7/10+ | Shawnee Browns/Chickasha Indians | Southwestern League | , | |
| George Hausman | hausma002geo | 1904 | 91 g. | Akron OH | Independent | , | |
| Sam Havel | havel-001edw | 1904 | 4/28-9/11 | Fort Wayne Railroaders | Central League | , | |
| John Haviland | havila001joh | 1904 | 5/7-9/5 | Keokuk Indians | Iowa League | , | |
| R.L. Hawkins | hawkin000rl- | 1904 | Univ. of Paris | , | |||
| Thomas Hawkins | hawkin001tho | 1904 | 4/28-9/11 | Dayton Veterans | Central League | , | |
| Pink Hawley | hawley001eme | 1904 | La Crosse WI | Independent | , | ||
| Jack Hayden | hayden001joh | 1904 | 4/29-9/28 | Baltimore Orioles | Eastern League | , | |
| Bruce Hayes | hayes-001bru | 1904 | 70 g. | Jackson Senators | Delta League | , | |
| Bruce Hayes | hayes-001bru | 1904 | 13 g. | Macon Highlanders | South Atlantic League | , | |
| Fred Hayes | hayes-002fre | 1904 | 5/16-6/7+ | Anniston | Tennessee-Alabama League | , | |
| Gerald Hayes | hayes-001ger | 1904 | 118 g. | Charleston Sea Gulls | South Atlantic League | , | |
| Jack Hayes | 1904 | Umpire | South Texas League | , | |||
| James Hayes | hayes-005jam | 1904 | Davenport River Rats | Illinois-Indiana-Iowa League | , | ||
| Thomas Hayes | hayes-002tom | 1904 | Burlington | Northern New York League | , | ||
| Tom Hayes | 1904 | Denver Grizzlies | Western League | , | |||
| William Hayward | haywar001wil | 1904 | 112 g. | New Haven Blues | Connecticut State League | , | |
| Ben Hayworth | haywor001ben | 1904 | 8/16 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Ben Hayworth | haywor001ben | 1904 | Vicksburg Hill Billies | Cotton States League | , | ||
| Hazeltine | 1904 | 5 g. | Kane PA | Independent | , | ||
| Doc Hazelton | hazlet001wil | 1904 | 4/20-6/13 | Toledo Mud Hens | American Association | , | |
| Doc Hazelton | hazlet001wil | 1904 | +8/24+ | Burlington | Northern New York League | , | |
| Thomas Healy/Healey | 1904 | 9/2-9/11 | South Bend Greens | Central League | , | ||
| Hughie Hearne | hearne001hug | 1904 | 5/4-9/28 | Baltimore Orioles | Eastern League | , | |
| C. R. Heath | 1904 | 5/11-5/15 | Wheeling Stogies | Central League | , | ||
| C. R. Heath | 1904 | 7/10 | Wheeling Stogies | Central League | , | ||
| Al Hecht | hecht-001al- | 1904 | Haverhill Hustlers | New England League | , | ||
| George Heckert | hecker001geo | 1904 | 5/3-10/1 | York Penn Parks | Tri-State League | , | |
| Alonzo Hedges | hedges001alo | 1904 | 25 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Lon? Hedges | 1904 | +5/11+ | 9 g. | Newark OH | Independent | , | |
| Henry Hees | hees--000hen | 1904 | GrFa-Mavericks | Independent | , | ||
| Jimmie Heffernan | heffer001jam | 1904 | +4/9-4/16+ | Syracuse Univ. | College | , | |
| Jimmie Heffernan | heffer001jam | 1904 | 6/29-9/8 | Addison White Sox | Southern Tier League | , | |
| Heffler | heffle000--- | 1904 | 4/30-5/1 | Denver Grizzlies | Western League | , | |
| Heflin | 1904 | +7/22+ | Heflin AL | Independent | , | ||
| Heggy | 1904 | +8/14+ | 16 g. | Canton OH | Independent | , | |
| Emmet Heidrick | heidri001joh | 1904 | 133 g. | St. Louis | American League | St. Louis, MO | |
| Edward Heimerl | heimer000edw | 1904 | Decatur Commodores | Illinois-Indiana-Iowa League | , | ||
| Edward Heimerl | heimer000edw | 1904 | Racine WI | Independent | , | ||
| Bill Heine | heine-001wil | 1904 | Addison White Sox | Southern Tier League | , | ||
| Frank Heinz | heinz-001fra | 1904 | 6/27-8/18 | San Antonio Bronchos | South Texas League | , | |
| Crese Heismann | heisma001chr | 1904 | 47 g. | Columbia Skyscrapers | South Atlantic League | , | |
| William Heitmuller | heitmu001wil | 1904 | Oakland | California State League | , | ||
| James Helms | helm--001jam | 1904 | Monroe Hill Citys | Cotton States League | , | ||
| James Helms | helm--001jam | 1904 | 9/19-9/23 | New Orleans Pelicans | Southern Association | , | |
| Frederick Helmsdorfer | helmsd001fre | 1904 | 4/26 | Colorado Springs Millionaires | Western League | , | |
| George Helmund | helmun001geo | 1904 | 5/6-9/18 | Syracuse Stars | New York State League | , | |
| George Hemming | hemmin002geo | 1904 | Springfield Ponies | Connecticut State League | , | ||
| Charlie Hemphill | hemphi001cha | 1904 | 114 g. | St. Louis | American League | St. Louis, MO | |
| Frank Hemphill | hemphi001fra | 1904 | 4/20-9/15 | Milwaukee Brewers | American Association | , | |
| Frank Hempleman | hemple001fra | 1904 | 38 g. | Charleston Sea Gulls | South Atlantic League | , | |
| Frank Hempleman | hemple001fra | 1904 | Savannah Pathfinders | South Atlantic League | , | ||
| Ben Henderson | hender003jam | 1904 | 4/26-5/4 | Omaha Rangers | Western League | , | |
| Ben Henderson | hender003jam | 1904 | 5/14 | Colorado Springs Millionaires | Western League | , | |
| Ben Henderson | hender003jam | 1904 | 58 g. | Fort Scott Giants | Missouri Valley League | , | |
| Robert? Henderson | 1904 | 7/5 | Beaumont Millionaires | South Texas League | , | ||
| Johnny Hendley | hendle001joh | 1904 | 82 g. | Iola Gasbags | Missouri Valley League | , | |
| Johnny Hendley | hendle001joh | 1904 | Fort Scott Giants | Missouri Valley League | , | ||
| Johnny Hendley | hendle001joh | 1904 | Leavenworth Orioles | Missouri Valley League | , | ||
| Newt Hendrix | hendri001new | 1904 | +5/9+ | 2 g. | Sheffield | Tennessee-Alabama League | , |
| Clarence Henley | henley001cla | 1904 | Sacramento | California State League | , | ||
| Clarence Henley | henley001cla | 1904 | Lodi | California State League | , | ||
| Weldon Henley | henley001wel | 1904 | 36 g. | Philadelphia | American League | Philadelphia, PA | |
| Joe Hennegar | henneg001jos | 1904 | 22 g. | Little Rock Travelers | Southern Association | , | |
| Joe Hennegar | henneg001jos | 1904 | 6/7-7/23 | Birmingham Barons | Southern Association | , | |
| Joe Hennegar | henneg001jos | 1904 | 7/25-9/24 | Shreveport Pirates | Southern Association | , | |
| Joe Hennessey | hennes001jos | 1904 | 5/11-7/23 | Shreveport Pirates | Southern Association | , | |
| Joe Hennessey | hennes001jos | 1904 | 7/25-9/24 | Birmingham Barons | Southern Association | , | |
| Lawrence Henretty | henret000lar | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| Henry | 1904 | 7/18 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | ||
| Henry | 1904 | Newburgh Taylor-mades | Hudson River League | , | |||
| George Henry | henry-002geo | 1904 | Springfield Ponies | Connecticut State League | , | ||
| George Henry | henry-002geo | 1904 | Hartford Senators | Connecticut State League | , | ||
| Jack Henry | henry-001joh | 1904 | 5/19-7/30 | Crookston Crooks | Northern League | , | |
| Jack Henry | henry-001joh | 1904 | +8/23-9/5 | Oskaloosa Quakers | Iowa League | , | |
| Hensel | 1904 | +6/27+ | La Crosse | Wisconsin State League | , | ||
| George Herberling | 1904 | Centerville IA | Independent | , | |||
| Frank Herbert | herber001fra | 1904 | 4/28-5/15 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Frank Herbert | herber001fra | 1904 | 6/2-7/7 | Dayton Veterans | Central League | , | |
| Jack Herbert | herber003joh | 1904 | 118 g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| Art Herman | herman001art | 1904 | 4/23-9/23 | Nashville Volunteers | Southern Association | , | |
| Peter Herman | herman007--- | 1904 | 6/28-7/22 | Colorado Springs Millionaires | Western League | , | |
| Joseph Herold | 1904 | Rushville IN | Independent | , | |||
| Eddie Herr | herr--002edw | 1904 | 4/24-5/25 | New Orleans Pelicans | Southern Association | , | |
| Eddie Herr | herr--002edw | 1904 | 14 g. | Charleston Sea Gulls | South Atlantic League | , | |
| Eddie Herr | herr--002edw | 1904 | 9/12-9/21 | Montgomery Senators | Southern Association | , | |
| Lefty Herring | herrin001sil | 1904 | 15 g. | Washington | American League | Washington, DC | |
| Frank Hershey | hershe001fra | 1904 | 5/7-9/16 | Ilion Typewriters | New York State League | , | |
| John Herwig | herwig001joh | 1904 | Chambersburg | Independent | , | ||
| John Herwig | herwig001joh | 1904 | 6/3-6/16 | Altoona Mountaineers | Tri-State League | , | |
| John Herwig | herwig001joh | 1904 | +7/8+ | Sharon PA | Independent | , | |
| John Herwig | herwig001joh | 1904 | Lodi | California State League | , | ||
| Hess | hess--001art | 1904 | 4/20-6/10 | Indianapolis Indians | American Association | , | |
| Hess | hess--001art | 1904 | 6/16- | 28 g. | Fargo | Northern League | , |
| Hess | 1904 | 6/23 | Utica Pent-Ups | New York State League | , | ||
| Hess | 1904 | +6/10-6/11+ | Winnipeg Maroons | Northern League | , | ||
| John Hess | hess--001joh | 1904 | 41 g. | Springfield Ponies | Connecticut State League | , | |
| Otto Hess | hess--001ott | 1904 | Cleveland | American League | Cleveland, OH | ||
| Tom Hess | hess--001tho | 1904 | 4/30-6/2 | Sioux City Soos | Western League | , | |
| Tom Hess | hess--001tho | 1904 | 6/16-7/24 | Grand Forks Forkers | Northern League | , | |
| Tom Hess | hess--001tho | 1904 | 7/29-9/3 | Waterloo Microbes | Iowa League | , | |
| Tom Hess | hess--001tho | 1904 | 9/5 | Dollar Bay | Copper Country League | , | |
| George Hessler | hessle001geo | 1904 | 5/5-5/6 | Sioux City Soos | Western League | , | |
| George Hessler | hessle001geo | 1904 | 5/20 | Denver Grizzlies | Western League | , | |
| George Hessler | hessle001geo | 1904 | 45 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| George Hessler | hessle001geo | 1904 | +7/22+ | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Larry Hesterfer | hester001law | 1904 | 4/29-9/27 | Newark Sailors | Eastern League | , | |
| Gus Hetling | hetlin001aug | 1904 | 122 g. | Springfield Midgets | Missouri Valley League | , | |
| Heverson | hevers000--- | 1904 | 6/14-6/15 | Rochester Bronchos | Eastern League | , | |
| Mike Heydon | heydon001mic | 1904 | 4/20-9/20 | Indianapolis Indians | American Association | , | |
| Mike Heydon | heydon001mic | 1904 | 4 g. | Chicago | American League | Chicago, IL | |
| William Heyniger | heynig000--- | 1904 | 7/21 | Corning White Ponies | Southern Tier League | , | |
| Hickey | hickey010--- | 1904 | 26 g. | Clarksdale | Delta League | , | |
| C. R. Hickey | 1904 | Fargo | Northern League | , | |||
| Eddie Hickey | hickey001edw | 1904 | 4/23-9/3 | Little Rock Travelers | Southern Association | , | |
| Fred Hickey | 1904 | no g. | Concord Marines | New England League | , | ||
| G. Fred Hickey | hickey002fre | 1904 | 5/12- | Nashua | New England League | , | |
| G. Fred Hickey | hickey002fre | 1904 | -7/26 | Manchester | New England League | , | |
| Jack Hickey | hickey002joh | 1904 | 8 g. | Seattle Siwashes | Pacific Coast League | , | |
| Jack Hickey | hickey002joh | 1904 | 5/16-9/18 | Columbus Senators | American Association | , | |
| Jack Hickey | hickey002joh | 1904 | 2 g. | Cleveland | American League | Cleveland, OH | |
| Mike Hickey | hickey001mik | 1904 | 4/30-9/17 | Lowell Tigers | New England League | , | |
| Walter Hickey | hickey001wal | 1904 | Toledo Mud Hens | American Association | , | ||
| Walter Hickey | hickey001wal | 1904 | Meriden Silverites | Connecticut State League | , | ||
| William Hickey | hickey005wil | 1904 | Peekskill | Hudson River League | , | ||
| Charles Hickman | hickma001cha | 1904 | 7/30-8/31 | Providence Grays | Eastern League | , | |
| Charles Hickman | hickma001cha | 1904 | 9/2- | Fall River Indians | New England League | , | |
| Charles Hickman | hickma001cha | 1904 | -9/11 | Concord Marines | New England League | , | |
| Charlie Hickman | hickma004cha | 1904 | 86 g. | Cleveland | American League | Cleveland, OH | |
| Charlie Hickman | hickma004cha | 1904 | 42 g. | Detroit | American League | Detroit, MI | |
| John Hickman | hickma001gor | 1904 | Monroe Hill Citys | Cotton States League | , | ||
| Rowe Hicks | hicks-001row | 1904 | Rich.-Brownies | Twin City League | , | ||
| William Higgins | 1904 | +7/14+ | St. Albans | Northern New York League | , | ||
| Charles Hilbert | hilber000--- | 1904 | no g. | Concord Marines | New England League | , | |
| Charles Hilbert | hilber000--- | 1904 | 6/6-6/20 | York Penn Parks | Tri-State League | , | |
| Charles Hilbert | hilber000--- | 1904 | 8/17-10/1 | Harrisburg Senators | Tri-State League | , | |
| Charles Hilbert | hilber000--- | 1904 | no g. | Manchester | New England League | , | |
| Charles Hilbert | hilber000--- | 1904 | Roch.-Navals | Rochester Indoor League | , | ||
| George Hildebrand | hildeb002geo | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| Belden Hill | hill--003bel | 1904 | 122 g. | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |
| Hugh Hill | hill--001hug | 1904 | 4/20-9/15 | Kansas City Blues | American Association | , | |
| Hugh Hill | hill--001hug | 1904 | -10/9 | 23 g. | St. Louis | National League | St. Louis, MO |
| Hunter Hill | hill--001hun | 1904 | 58 g. | St. Louis | American League | St. Louis, MO | |
| Hunter Hill | hill--001hun | 1904 | 77 g. | Washington | American League | Washington, DC | |
| Arthur Hillebrand | hilleb001art | 1904 | Washington | American League | Washington, DC | ||
| Arthur Hillebrand | hilleb001art | 1904 | Princeton Univ. | College | , | ||
| Clarence Hillebrand | 1904-05 | Princeton Univ. | College | , | |||
| Homer Hillebrand | hilleb001hom | 1904 | Washington | American League | Washington, DC | ||
| Ed Hilley | hilley001edw | 1904 | 5/6-9/17 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Hillinger | 1904 | 5/23-5/25 | Evansville River Rats | Central League | , | ||
| Hillock | hilloc001--- | 1904 | 5/31-7/15 | Fargo | Northern League | , | |
| Jack Himes | himes-001joh | 1904 | 122 g. | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |
| Bill Hinchman | hinchm001wil | 1904 | 5/6-9/18 | Ilion Typewriters | New York State League | , | |
| Harry Hinchman | hinchm001har | 1904 | 5/6-9/18 | Ilion Typewriters | New York State League | , | |
| Hunkey Hines | hines-001hun | 1904 | 22 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| Jacob Hines | hines-001jac | 1904 | +8/4-8/17 | Knoxville | Tennessee-Alabama League | , | |
| Hinton | 1904 | no g. | Charleston Sea Gulls | South Atlantic League | , | ||
| John Hinton | hinton001joh | 1904 | 5/11-9/10 | Altoona Mountaineers | Tri-State League | , | |
| Arthur Hippert | hipper001gar | 1904 | 21 g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| Arthur Hippert | hipper001gar | 1904 | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | ||
| Arthur Hippert | hipper001gar | 1904 | +7/27+ | 12 g. | Oskaloosa Quakers | Iowa League | , |
| Arthur Hippert | hipper001gar | 1904 | 9 g. | Leavenworth Orioles | Missouri Valley League | , | |
| Bert Hise | hise--001ber | 1904 | 4/27-6/12 | Corsicana Oil Citys | Texas League | , | |
| Bert Hise | hise--001ber | 1904 | 6/16-9/2 | Galveston Sand Crabs | South Texas League | , | |
| Hisey | hisey-002--- | 1904 | +7/4+ | Dickinson ND | Independent | , | |
| Leo Hite | hite--001leo | 1904 | 6 g. | Leavenworth Orioles | Missouri Valley League | , | |
| Leo Hite | hite--001leo | 1904 | Guthrie Blues | Southwestern League | , | ||
| Roy Hitt | hitt--001roy | 1904 | Los Angeles Angels | Pacific Coast League | , | ||
| Roy Hitt | hitt--001roy | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| William Hoagland | 1904 | -7/? | Umpire | Tri-State League | , | ||
| William Hoagland | 1904 | ?-8/25+ | Umpire | New York State League | , | ||
| Herman Hoar | hoar--001her | 1904 | 5/3-8/9 | Manchester | New England League | , | |
| Allan Hobbs | 1904-07 | Guilford College | College | , | |||
| Frank Hobbs | hobbs-001fra | 1904 | 5/6-9/5 | Oskaloosa Quakers | Iowa League | , | |
| Louis Hobbs | 1904-07 | Guilford College | College | , | |||
| Hobgood | hobgoo000--- | 1904 | 3/11-4/4+ | U. North Carolina | College | , | |
| Harry Hoch | hoch--001har | 1904-07 | Kutztown Univ. | College | , | ||
| Hodge | hodge-010--- | 1904 | 1 g. | Oakland Oaks | Pacific Coast League | , | |
| Carson Hodge | hodge-001car | 1904 | 36 g. | Meriden Silverites | Connecticut State League | , | |
| Carson Hodge | hodge-001car | 1904 | Holyoke Paperweights | Connecticut State League | , | ||
| Gerry Hodge | hodge-001ger | 1904 | 5/8-9/4 | Olympia Senators | Southwest Washington League | , | |
| F. W. Hodgkins | hodgki001--- | 1904 | 65 g. | Yazoo City Zoos | Delta League | , | |
| George Hodson | hodson002geo | 1904 | 4/29-9/24 | St. Joseph Saints | Western League | , | |
| Art Hoelskoetter | hoelsk001art | 1904 | 5/1-9/23 | Denver Grizzlies | Western League | , | |
| Ike Hoepple | hoeppl000ike | 1904 | Springfield Hustlers | Illinois-Indiana-Iowa League | , | ||
| Ike Hoepple | hoeppl000ike | 1904 | +6/5- | 24 g. | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , |
| Jack Hoey | hoey--001joh | 1904-05 | Holy Cross Col. | College | , | ||
| Augie Hoff | hoff--001aug | 1904 | 70 g. | New London Whalers | Connecticut State League | , | |
| Bill Hoffer | hoffer003wil | 1904 | 4/27-9/22 | Des Moines Prohibitionists | Western League | , | |
| Hoffman | 1904 | 10 g. | Fort Scott Giants | Missouri Valley League | , | ||
| Hoffman | 1904 | Pittsburg Coal Diggers | Missouri Valley League | , | |||
| Danny Hoffman | hoffma001dan | 1904 | Philadelphia | American League | Philadelphia, PA | ||
| Fred Hoffman | hoffma001fre | 1904 | 430 ab | Greenville Cotton Pickers | Cotton States League | , | |
| Henry Hoffman | hoffma001h-- | 1904 | no g. | Jacksonville Jays | South Atlantic League | , | |
| Henry Hoffman | hoffma001h-- | 1904 | 118 g. | Macon Highlanders | South Atlantic League | , | |
| Izzy Hoffman | hoffma004har | 1904 | 4/14- | 10 g. | Washington | American League | Washington, DC |
| Izzy Hoffman | hoffma004har | 1904 | 5/17-7/20 | Montreal Royals | Eastern League | , | |
| Izzy Hoffman | hoffma004har | 1904 | 7/26-9/30 | Lebanon | Tri-State League | , | |
| Larry Hoffman | hoffma001law | 1904 | 18 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Oscar Hoffman | hoffma019--- | 1904 | +5/25-7/25+ | Crookston Crooks | Northern League | , | |
| Jesse Hoffmeister | hoffme002jes | 1904 | 4/27-5/30 | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Jesse Hoffmeister | hoffme002jes | 1904 | +6/9- | 34 g. | Crookston Crooks | Northern League | , |
| Solly Hofman | hofman001art | 1904 | 4/24-9/25 | Des Moines Prohibitionists | Western League | , | |
| Solly Hofman | hofman001art | 1904 | 7 g. | Chicago | National League | Chicago, IL | |
| Marty Hogan | hogan-002mar | 1904 | 6/17 | Youngstown OH | Independent | , | |
| Wallace Hogan | hogan-002wal | 1904 | 127 g. | Tacoma Tigers | Pacific Coast League | , | |
| Bill Hogg | hogg--002wil | 1904 | 4/28-9/21 | Spokane Indians | Pacific National League | , | |
| Bill Hogg | hogg--002wil | 1904 | 14 g. | Portland Browns | Pacific Coast League | , | |
| Bill Hogg | hogg--002wil | 1904 | Seattle Siwashes | Pacific Coast League | , | ||
| George Hogreiver | hogrie001geo | 1904 | 4/20-9/20 | Indianapolis Indians | American Association | , | |
| Bradley Hogue | hogue-001b-- | 1904 | 5/16- | Augusta Tourists | South Atlantic League | , | |
| Bradley Hogue | hogue-001b-- | 1904 | +6/4-6/18+ | Anniston | Tennessee-Alabama League | , | |
| Bradley Hogue | hogue-001b-- | 1904 | Jackson Senators | Delta League | , | ||
| Holbrook | holbro003--- | 1904 | 6/19 | Centralia Midgets | Southwest Washington League | , | |
| Walter Holcomb | holcom001wal | 1904 | 33 g. | Boone Coal Miners | Iowa League | , | |
| Jack Holland | hollan004joh | 1904 | 124 g. | Spokane Indians | Pacific National League | , | |
| Jack Holland | hollan004joh | 1904 | 26 g. | Portland Browns | Pacific Coast League | , | |
| Michael Hollander | hollan003mic | 1904 | 5/9-5/31 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Michael Hollander | hollan003mic | 1904 | Hudson Marines | Hudson River League | , | ||
| Bug Holliday | hollid001bug | 1904 | 4/20-7/24 | Umpire | American Association | , | |
| James Holliday | hollid001jam | 1904 | +5/20+ | Fort Scott Giants | Missouri Valley League | , | |
| Wallace Hollingsworth | hollin001wal | 1904 | 4/21-6/13 | Atlanta Crackers | Southern Association | , | |
| Wallace Hollingsworth | hollin001wal | 1904 | 6/23-6/26 | Montgomery Senators | Southern Association | , | |
| Wallace Hollingsworth | hollin001wal | 1904 | 6/27-6/28 | Atlanta Crackers | Southern Association | , | |
| Wallace Hollingsworth | hollin001wal | 1904 | 7/6-8/3 | Birmingham Barons | Southern Association | , | |
| Wallace Hollingsworth | hollin001wal | 1904 | 9/10-9/12 | Ilion Typewriters | New York State League | , | |
| Harvey Hollis | hollis001har | 1904 | 5/3- | Haverhill Hustlers | New England League | , | |
| Harvey Hollis | hollis001har | 1904 | -7/5 | Nashua | New England League | , | |
| Ed Holly | holly-002edw | 1904 | 4/23-5/15 | New Orleans Pelicans | Southern Association | , | |
| Ed Holly | holly-002edw | 1904 | 5/18-6/18 | Shreveport Pirates | Southern Association | , | |
| Ed Holly | holly-002edw | 1904 | 6/19-9/25 | New Orleans Pelicans | Southern Association | , | |
| Holmes | 1904 | Nashville Volunteers | Southern Association | , | |||
| Holmes | 1904 | 8/4 | Wheeling Stogies | Central League | , | ||
| Clarence Holmes | holmes001cla | 1904 | 33 g. | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |
| Ducky Holmes | holmes003jam | 1904 | 68 g. | Chicago | American League | Chicago, IL | |
| Ducky Holmes | holmes001how | 1904 | 90 g. | Savannah Pathfinders | South Atlantic League | , | |
| Fred Holmes | holmes001fre | 1904 | 4/24 | Chicago | National League | Chicago, IL | |
| Jim Holmes | holmes002jam | 1904 | 5/16-8/19 | Huntsville | Tennessee-Alabama League | , | |
| Scott Holmes | holmes002jam | 1904 | Huntsville | Tennessee-Alabama League | , | ||
| Thomas Holness | holnes001--- | 1904 | Victoria BC | Independent | , | ||
| Earl Holt | holt--001ear | 1904 | Asheville | Carolina Interstate League | , | ||
| Earl Holt | holt--001ear | 1904-30 | Oak Ridge Inst. | Military Academy | , | ||
| Pearl Holycross | holycr001pea | 1904 | 34+ g. | Cairo Champions | Kentucky-Illinois-Tennessee League | , | |
| Bob Hook | hook--001--- | 1904 | 17 g. | Charleston Sea Gulls | South Atlantic League | , | |
| Buck Hooker | hooker001wil | 1904 | 5/3-7/5 | Lowell Tigers | New England League | , | |
| Ernest Hooker | hooker001e-- | 1904 | 5/4-6/18 | Providence Grays | Eastern League | , | |
| Ernest Hooker | hooker001e-- | 1904 | 8/11 | Toledo Mud Hens | American Association | , | |
| Ernest Hooker | hooker001e-- | 1904 | 9/19-9/28 | Providence Grays | Eastern League | , | |
| Kirby Hoon | hoon--001kir | 1904 | 6/3-9/25 | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Harry Hooper | hooper001har | 1904-07 | St. Mary’s Col. | College | , | ||
| William Hoopes | hoopes000wil | 1904 | 5/3-5/11 | Camden | Tri-State League | , | |
| William Hoopes | hoopes000wil | 1904 | 6/2-6/24 | Nashua | New England League | , | |
| Hoover | hoover008--- | 1904 | 5/5-5/29 | Camden | Tri-State League | , | |
| Sam Hope | hope--001sam | 1904 | , | ||||
| Bill Hopke | hopke-001wil | 1904 | 4/28-9/11 | Fort Wayne Railroaders | Central League | , | |
| Hopkins | 1904 | 4 g. | Akron OH | Independent | , | ||
| Buck Hopkins | hopkin004joh | 1904 | Newport News | Independent | , | ||
| Lee Hopkins | hopkin001leo | 1904 | Rock Island Islanders | Illinois-Indiana-Iowa League | , | ||
| Lee Hopkins | hopkin001leo | 1904 | Maquoketa IA | Independent | , | ||
| Sis Hopkins | hopkin002a-- | 1904 | 4/23-5/9 | Birmingham Barons | Southern Association | , | |
| Sis Hopkins | hopkin002a-- | 1904 | 5/16-6/10+ | Bessemer | Tennessee-Alabama League | , | |
| Sis Hopkins | hopkin002a-- | 1904 | +6/12-6/27 | Huntsville | Tennessee-Alabama League | , | |
| Sis Hopkins | hopkin002a-- | 1904 | 6/30-7/6 | Decatur | Tennessee-Alabama League | , | |
| Sis Hopkins | hopkin002a-- | 1904 | 12 g. | Yazoo City Zoos | Delta League | , | |
| William Hopper | 1904 | 14 g. | Warren OH | Independent | , | ||
| Tony Horath | horath001ant | 1904 | 120 g. | Fort Scott Giants | Missouri Valley League | , | |
| William Horn | horn--001cas | 1904 | 5/5-6/9 | San Antonio Bronchos | South Texas League | , | |
| William Horn | horn--001cas | 1904 | 8/15-9/12 | Grand Rapids Orphans | Central League | , | |
| William Horrell | 1904 | Salina-Invincibles | Independent | , | |||
| Elmer Horton | horton002elm | 1904 | 5/24-8/6 | Utica Pent-Ups | New York State League | , | |
| Elmer Horton | horton002elm | 1904 | 8/14-8/19 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Harry Horton | horton002har | 1904 | 41 g. | Springfield Midgets | Missouri Valley League | , | |
| Wilson Hosmer | hosmer002wil | 1904 | 5/9-5/13 | Binghamton Bingoes | New York State League | , | |
| Wilson Hosmer | hosmer002wil | 1904 | Newburgh Taylor-mades | Hudson River League | , | ||
| William Hoster | hoster001wil | 1904 | 12 g. | Fort Scott Giants | Missouri Valley League | , | |
| William Hoster | hoster001wil | 1904 | Pittsburg Coal Diggers | Missouri Valley League | , | ||
| William Houghton | hought001wil | 1904 | 8/24-9/17 | Lawrence Colts | New England League | , | |
| Dennis Houle | houle-001den | 1904 | +6/30-9/17 | Umpire | New York State League | , | |
| John House | house-001joh | 1904 | 5/7-9/5 | Marshalltown Grays | Iowa League | , | |
| John House | house-001joh | 1904 | 9/16-9/20 | Minneapolis Millers | American Association | , | |
| Ed Householder | househ001edw | 1904 | 4/23-8/18 | Little Rock Travelers | Southern Association | , | |
| Ed Householder | househ001edw | 1904 | 8/23-8/29 | St. Paul Saints | American Association | , | |
| Ed Householder | househ001edw | 1904 | 8/30-9/7 | Columbus Senators | American Association | , | |
| Ed Householder | househ001edw | 1904 | 9/11-9/20 | St. Paul Saints | American Association | , | |
| Benjamin Houser | houser001ben | 1904 | Kentucky-Illinois-Tennessee League | , | |||
| Robert Houston | housto001rob | 1904 | 5/16-6/1+ | Knoxville | Tennessee-Alabama League | , | |
| Robert Houston | housto001rob | 1904 | 233 ab | Greenville Cotton Pickers | Cotton States League | , | |
| Lefty Houtz | houtz-001fre | 1904 | 124 g. | Boise Fruit Pickers | Pacific National League | , | |
| Del Howard | howard001geo | 1904 | 4/24-9/25 | Omaha Rangers | Western League | , | |
| Earl Howard | howard001ear | 1904 | 5/19- | 57 g. | Winnipeg Maroons | Northern League | , |
| Ernie Howard | howard002ern | 1904 | 366 ab | Baton Rouge Red Sticks | Cotton States League | , | |
| Leslie Howard | howard001les | 1904 | 1 g. | Decatur | Tennessee-Alabama League | , | |
| Leslie Howard | howard001les | 1904 | +6/14-7/8 | Anniston | Tennessee-Alabama League | , | |
| Howell | 1904 | 18 g. | Sharon OH | Independent | , | ||
| Howell | howell015--- | 1904 | Visalia CA | Independent | , | ||
| Howell | howell015--- | 1904 | 4/727-6/9 | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Frank Howell | howell002f-- | 1904 | Dickinson ND | Independent | , | ||
| Harry Howell | howell001hen | 1904 | St. Louis | American League | St. Louis, MO | ||
| Robert Howell | howell001rob | 1904 | 79 g. | Pittsburg Coal Diggers | Missouri Valley League | , | |
| Howells | howell003--- | 1904 | 85 ab | Newburgh Taylor-mades | Hudson River League | , | |
| Billy Howells | howell005wil | 1904 | 46 g. | Winnipeg Maroons | Northern League | , | |
| William Howie | howie-001wil | 1904 | 49 g. | Topeka Saints | Missouri Valley League | , | |
| Jimmie Hoy | hoy---002jam | 1904 | Fort Scott Giants | Missouri Valley League | , | ||
| Jimmie Hoy | hoy---002jam | 1904 | +6/23-9/5 | Marshalltown Grays | Iowa League | , | |
| Arthur Hubbard | hubbar001a-- | 1904 | 5/21-8/15 | Fort Worth Panthers | Texas League | , | |
| Arthur Hubbard | hubbar001a-- | 1904 | +8/27 | Wichita Falls | Western Texas | , | |
| Harry Huber | huber-001har | 1904 | +9/12+ | 37 g. | Butte Miners/Fruit Pickers | Pacific National League | , |
| Leo Huber | huber-001leo | 1904 | 73 g. | Jackson Senators | Delta League | , | |
| Thomas Huddleston | huddle001tho | 1904 | 4/29-8/15 | Corsicana Oil Citys | Texas League | , | |
| Thomas Huddleston | huddle001tho | 1904 | 9/7-9/17 | Little Rock Travelers | Southern Association | , | |
| Hudson | 1904 | 12 g. | Canton OH | Independent | , | ||
| Marvin Hudson | 1904 | 5/14 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | ||
| Marvin Hudson | 1904 | Popular Bluff MO | Independent | , | |||
| Frank Huelsman | huelsm001fra | 1904 | 3 g. | Chicago | American League | Chicago, IL | |
| Frank Huelsman | huelsm001fra | 1904 | 4 g. | Detroit | American League | Detroit, MI | |
| Frank Huelsman | huelsm001fra | 1904 | 1 g. | Chicago | American League | Chicago, IL | |
| Frank Huelsman | huelsm001fra | 1904 | 20 g. | St. Louis | American League | St. Louis, MO | |
| Frank Huelsman | huelsm001fra | 1904 | 84 g. | Washington | American League | Washington, DC | |
| George Huff | huff--002geo | 1904 | , | ||||
| Tobe Huffman | hauffm001--- | 1904 | Atchison KS | Independent | , | ||
| Tobe Huffman | hauffm001--- | 1904 | +6/7+ | Fort Scott Giants | Missouri Valley League | , | |
| Jack Huffmeister | huffme001jac | 1904 | +5/14- | Guthrie Blues | Southwestern League | , | |
| Jack Huffmeister | huffme001jac | 1904 | 6/30-7/29 | Dallas Giants | Texas League | , | |
| Jack Huffmeister | huffme001jac | 1904 | 8/7 | Yazoo City Zoos | Texas League | , | |
| Jack Huffmeister | huffme001jac | 1904 | -9/27+ | Guthrie Blues | Southwestern League | , | |
| Ed Hug | hug---001edw | 1904 | 49+ g. | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | |
| Miller Huggins | huggin001mil | 1904 | Cincinnati | National League | Cincinnati, OH | ||
| Billie Hughes | hughes008wil | 1904 | Guthrie Blues | Southwestern League | , | ||
| Ed Hughes | hughes004edw | 1904 | 12 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| George Hughes | hughes003geo | 1904 | 121 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| James Hughes | hughes004jam | 1904 | 56+ g. | Cairo Champions | Kentucky-Illinois-Tennessee League | , | |
| James Hughes | hughes001j-- | 1904 | 67 g. | Duluth White Sox | Northern League | , | |
| John Hughes | hughes001joh | 1904 | Saugerties | Hudson River League | , | ||
| Tom Hughes | hughes004tho | 1904 | New York | American League | New York, NY | ||
| Tom Hughes | hughes004tho | 1904 | Washington | American League | Washington, DC | ||
| Tom Hughes | hughes005tho | 1904 | 47 g. | Pittsburg Coal Diggers | Missouri Valley League | , | |
| Tom Hughes | hughes005tho | 1904 | Topeka Saints | Missouri Valley League | , | ||
| Tommy Hughes | hughes000tom | 1904 | Wash. & Jefferson | College | , | ||
| Tommy Hughes | hughes000tom | 1904 | Youngstown OH | Independent | , | ||
| William Hughes | hughes008wil | 1904 | +5/13+ | Guthrie Blues | Southwestern League | , | |
| William Hughes | hughes008wil | 1904 | Ardmore IT | Independent | , | ||
| William Hughes | hughes008wil | 1904 | 8/5-8/15 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| William Hughes | hughes001wil | 1904 | 6/29-9/10 | Elmira | Southern Tier League | , | |
| Jim Hughey | hughey001jim | 1904 | 5/12-8/5 | Shreveport Pirates | Southern Association | , | |
| Hule | hule--001--- | 1904 | Superior Longshoremen | Northern League | , | ||
| Thomas Huling | huling001tho | 1904 | +7/8+ | Zanesville OH | ProtAssn | , | |
| Hull | hull--003--- | 1904 | 5/18 | Knoxville | Tennessee-Alabama League | , | |
| Rudy Hulswitt | hulswi001rud | 1904 | 113 g. | Philadelphia | National League | Philadelphia, PA | |
| John Hummel | hummel001joh | 1904 | 5/17-8/27 | Wilmington Peaches | Tri-State League | , | |
| Charles Humphrey | humphr002cha | 1904 | New London Whalers | Connecticut State League | , | ||
| Hunt | 1904 | 20 g. | Kent OH | Independent | , | ||
| Carl Hunt | hunt--001car | 1904 | 5/1- | Enid Evangelists | Southwestern League | , | |
| Bill Hunter | hunter003bil | 1904 | 6/9 | Roseburg Shamrocks | Oregon State League | , | |
| Frederick Hunter | hunter002fre | 1904 | 4/28-7/16 | Dallas Giants | Texas League | , | |
| Frederick Hunter | hunter002fre | 1904 | -9/2 | 48 g. | Beaumont Millionaires | South Texas League | , |
| Slats Hunter | hunter000sla | 1904 | 5/1-7/4 | Roseburg Shamrocks | Oregon State League | , | |
| Dan Hupp | hupp--002dan | 1904 | 110 g. | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |
| Dan Hupp | hupp--002dan | 1904 | Rock Island Islanders | Illinois-Indiana-Iowa League | , | ||
| Dan Hupp | hupp--002dan | 1904 | +7/31+ | Marshalltown Grays | Iowa League | , | |
| Ed Hurlburt | hurlbu001edw | 1904 | 6/20-9/23 | Memphis Egyptians | Southern Association | , | |
| George Hurlburt | hurlbu001geo | 1904 | 4/24-5/28 | Sioux City Soos | Western League | , | |
| George Hurlburt | hurlbu001geo | 1904 | +6/3-7/6+ | Burlington River Rats | Iowa League | , | |
| George Hurlburt | hurlbu001geo | 1904 | +7/12-7/24 | Grand Forks Forkers | Northern League | , | |
| George Hurlburt | hurlbu001geo | 1904 | 33 g. | Topeka Saints | Missouri Valley League | , | |
| George Hurlburt | 1904 | 7/9 | Ilion Typewriters | New York State League | , | ||
| Hurley | hurley021--- | 1904 | 7/1-7/7 | Penn Yan Grape Pickers | Southern Tier League | , | |
| Bill Hurley | hurley003wil | 1904 | 4/23-7/23 | Little Rock Travelers | Southern Association | , | |
| Bill Hurley | hurley003wil | 1904 | 44 g. | Portland Browns | Pacific Coast League | , | |
| Jerry Hurley | hurley001jer | 1904 | 5/6-9/17 | Binghamton Bingoes | New York State League | , | |
| John Hurst | hurst-001joh | 1904 | 5/7-9/5 | Marshalltown Grays | Iowa League | , | |
| Max Hurst | 1904 | Umpire | Tri-State League | , | |||
| Huston | 1904 | +7/11+ | Greenville Cotton Pickers | Cotton States League | , | ||
| Harry Huston | huston001har | 1904 | 7/5-7/19 | Sioux City Soos | Western League | , | |
| Harry Huston | huston001har | 1904 | 47 g. | Leavenworth Orioles | Missouri Valley League | , | |
| Jack Huston | huston001jac | 1904 | Umpire | Pacific Coast League | , | ||
| Jack Huston | huston001jac | 1904 | 7/1-7/4 | Umpire | Oregon State League | , | |
| Edward Hutchcroft | hutchc001ed- | 1904 | +5/19-8/3+ | Sheffield | Tennessee-Alabama League | , | |
| Ed Hutchinson | hutchi002ed- | 1904 | 42 g. | Grand Forks Forkers | Northern League | , | |
| Fred Hutchinson | hutchi001fre | 1904 | Muskogee IT | Independent | , | ||
| Fred Hutchinson | hutchi001fre | 1904 | Tulsa IT | Independent | , | ||
| Ralph Hutchinson | hutchi002ral | 1904 | 5/27- | 42 g. | Grand Forks Forkers | Northern League | , |
| Ralph Hutchinson | hutchi002ral | 1904 | 7/28-9/16 | Sioux City Soos | Western League | , | |
| Amos Hutter | hutter001amo | 1904 | 69 g. | Sedalia Goldbugs | Missouri Valley League | , | |
| W. A. Hutton | hutton000bil | 1904 | Medford | Rogue River Valley | , | ||
| W. A. Hutton | hutton000bil | 1904 | 5/21 | Roseburg Shamrocks | Oregon State League | , | |
| Will Hutton | hutton001wil | 1904 | 8/4- | 7 g. | Knoxville | Tennessee-Alabama League | , |
| Ham? Hyatt | hyatt-003--- | 1904 | 8/7-9/4 | Hoquiam Perfect Gentlemen | Southwest Washington League | , | |
| William Hycoop | hycoop000wil | 1904 | +8/16+ | Kazoo Stars | Independent | , | |
| Carl Hyde | hyde--001car | 1904 | 8/17-9/12 | Grand Rapids Orphans | Central League | , | |
| Hyman | 1904 | Canton OH | Independent | , | |||
| Pat Hynes | hynes-001pat | 1904 | -10/9 | 66 g. | St. Louis | American League | St. Louis, MO |
| Ham Iburg | iburg-001her | 1904 | Portland Browns | Pacific Coast League | , | ||
| Frank Ingalls | ingall001fra | 1904 | Lodi | California State League | , | ||
| Frank Ingalls | ingall001fra | 1904 | Stockton | California State League | , | ||
| Ingels | ingels000--- | 1904 | 5/5 | Des Moines Prohibitionists | Western League | , | |
| Happy Iott | iott--001fre | 1904 | 4/30-6/20 | Fall River Indians | New England League | , | |
| Happy Iott | iott--001fre | 1904 | 7/5-9/10 | Altoona Mountaineers | Tri-State League | , | |
| Charles Irby | irby--001cha | 1904 | Ritzville WA | Independent | , | ||
| Irwin | irwin-013--- | 1904 | 9/11 | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Arthur Irwin | irwin-001art | 1904 | 4/29-7/13 | Toronto Maple Leafs | Eastern League | , | |
| Arthur Irwin | irwin-001art | 1904 | 8/?-9/20 | Kansas City Blues | American Association | , | |
| Charlie Irwin | irwin-001cha | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| William Irwin | irvin-001wil | 1904 | Kingston Colonials | Hudson River League | , | ||
| John Isbell | isbell001war | 1904 | 4/21-9/20 | Kansas City Blues | American Association | , | |
| Albert Ittig | ittig-001alb | 1904 | 38 g. | Savannah Pathfinders | South Atlantic League | , | |
| Albert Ittig | ittig-001alb | 1904 | Columbia Skyscrapers | South Atlantic League | , | ||
| Henry Iverson | iverso001hen | 1904 | Sacramento | California State League | , | ||
| Henry Iverson | iverso001hen | 1904 | Lodi | California State League | , | ||
| Ives | ives--001geo | 1904 | 110 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Fred Jacklitsch | jackli001fre | 1904 | 26 g. | Brooklyn | National League | Brooklyn, NY | |
| Jackson | 1904 | 9/2-9/4 | Wheeling Stogies | Central League | , | ||
| Charles Jackson | jackso005cha | 1904 | 5/2-8/14 | Fort Worth Panthers | Texas League | , | |
| Charles Jackson | jackso005cha | 1904 | 3 g. | Oakland Oaks | Pacific Coast League | , | |
| Herbert Jackson | jackso001cha | 1904 | 5/5-6/8 | Williamsport Millionaires | Tri-State League | , | |
| Herbert Jackson | jackso001cha | 1904 | 7/10-8/24 | York Penn Parks | Tri-State League | , | |
| Herbert Jackson | jackso001cha | 1904 | 9/17-9/26 | Providence Grays | Eastern League | , | |
| Jim Jackson | jackso002jam | 1904 | 4/20-9/20 | St. Paul Saints | American Association | , | |
| William Jackson | 1904 | 23 g. | Youngstown OH | Independent | , | ||
| William Jackson | 1904 | Niles OH | Independent | , | |||
| William Jackson | 1904 | Warren OH | Independent | , | |||
| Mike Jacob | jacobs001mor | 1904 | Denver Grizzlies | Western League | , | ||
| Mike Jacob | jacobs001mor | 1904 | 5/5-6/10 | Evansville River Rats | Central League | , | |
| Mike Jacob | jacobs001mor | 1904 | 59 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Moses Jacobs | 1904 | Columbia Skyscrapers | South Atlantic League | , | |||
| Beany Jacobson | jacobs001alb | 1904 | 4/30- | 33 g. | Washington | American League | Washington, DC |
| Jacob Jacoby | jacoby001jac | 1904 | Easton PA | , | |||
| Jacob Jacoby | jacoby001jac | 1904 | Bangor ME | , | |||
| Charlie Jaeger | jaeger001cha | 1904 | 42 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| Charlie Jaeger | jaeger001cha | 1904 | 9/9-10/7 | Detroit | American League | Detroit, MI | |
| Dickey James | 1904 | Akron OH | Independent | , | |||
| Richard James | james-002ric | 1904 | Evansville River Rats | Central League | , | ||
| Richard James | james-002ric | 1904 | Akron OH | Independent | , | ||
| Robert James | james-002rob | 1904 | 9 g. | Seattle Siwashes | Pacific Coast League | , | |
| W. A. James | james-012--- | 1904 | +5/23-8/18+ | Columbia | Tennessee-Alabama League | , | |
| W. A. James | james-012--- | 1904 | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | ||
| F. O. Jamieson | 1904 | 5/7-9/5 | Waterloo Microbes | Iowa League | , | ||
| Frank Jansa | jansa-001fra | 1904 | +5/29+ | Bellingham WA | Independent | , | |
| Henry Jansing | jansin001hen | 1904 | 4/21-9/2 | Montgomery Senators | Southern Association | , | |
| Ferd Jarrott | jarrot001fer | 1904 | 4/24-9/25 | Sioux City Soos | Western League | , | |
| Jack Jarvis | jarvis005wil | 1904 | 4/28-8/3 | Fort Worth Panthers | Texas League | , | |
| Jack Jarvis | jarvis005wil | 1904 | 8/5-8/30 | Beaumont Millionaires | South Texas League | , | |
| Jeffries | 1904 | Leavenworth Orioles | Missouri Valley League | , | |||
| A. G. Jeffries | jeffri001a-- | 1904 | 7/30-8/15 | Dallas Giants | Texas League | , | |
| A. G. Jeffries | jeffri001a-- | 1904 | Guthrie Blues | Southwestern League | , | ||
| Charles Jeffries | jeffri001cha | 1904 | Johnstown Johnnies | Pennsylvania League | , | ||
| Frank Jeffries | 1904 | Norwich Reds | Connecticut State League | , | |||
| Jim Jeffries | jeffri001j-- | 1904 | 54+ g. | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |
| J. E. Jegglin | jeggli001j-- | 1904 | 9/22- | Wild’s Browns | Independent | , | |
| Jenkins | 1904 | 19 g. | Kent OH | Independent | , | ||
| Fred Jenkins | jenkin002fre | 1904 | 5/7-9/5 | Keokuk Indians | Iowa League | , | |
| Hughie Jennings | jennin001hug | 1904 | 5/10-9/27 | Baltimore Orioles | Eastern League | , | |
| Si Jensen | jensen001erv | 1904 | 5/5- | Salt Lake City Elders | Pacific National League | , | |
| Joe Jerger | jerger001jos | 1904 | 5/4-9/17 | Fall River Indians | New England League | , | |
| Carl Jessup | jessup001car | 1904 | no g. | New York State League | , | ||
| Clarence Jessup | jessup001cla | 1904 | +7/4+ | Richmond IN | Independent | , | |
| Clarence Jessup | jessup001cla | 1904 | 7/19-9/2 | Grand Rapids Orphans | Central League | , | |
| Johns | 1904 | , | |||||
| Ollie Johns | johns-001oli | 1904 | 5/1-9/10 | Dayton Veterans | Central League | , | |
| Johnson | johnso247--- | 1904 | Portl.-Monograms | Independent | , | ||
| Johnson | johnso247--- | 1904 | 4/28-5/15 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Johnson | johnso247--- | 1904 | 5/18-7/4 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Johnson | johnso122--- | 1904 | 1 g. | Bessemer | Tennessee-Alabama League | , | |
| Johnson | johnso017--- | 1904 | +6/29+ | 6 g. | Chattanooga | Tennessee-Alabama League | , |
| Johnson | johnso092--- | 1904 | 2 g. | Knoxville | Tennessee-Alabama League | , | |
| Johnson | johnso262--- | 1904 | +5/11-5/18+ | Keokuk Indians | Iowa League | , | |
| Abbie Johnson | johnso002abb | 1904 | 5/6-5/11 | Utica Pent-Ups | New York State League | , | |
| F. Johnson | johnso004f-- | 1904 | +6/10-6/14+ | Oskaloosa Quakers | Iowa League | , | |
| Guy Johnson | johnso003guy | 1904 | U. of Michigan | College | , | ||
| Harold Johnson | johnso004har | 1904 | 5/7-8/6+ | Waterloo Microbes | Iowa League | , | |
| Harold Johnson | johnso004har | 1904 | +8/20=8/26+ | Marshalltown Grays | Iowa League | , | |
| John Johnson | johnso001ral | 1904 | 4/28-5/8 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| John Johnson | johnso001ral | 1904 | 5/9 | Urbana OH | Independent | , | |
| John Johnson | johnso001ral | 1904 | 6/29-7/30 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| John Johnson | johnso001ral | 1904 | 7/31-8/14 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Len Johnson | johnso001len | 1904 | 5/7-6/13+ | Oskaloosa Quakers | Iowa League | , | |
| Leonard Johnson | johnso008leo | 1904 | 6/26 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Leonard Johnson | johnso008leo | 1904 | 7/18-8/4 | Corsicana Oil Citys | Texas League | , | |
| Leonard Johnson | johnso008leo | 1904 | 8/14 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Otis Johnson | johnso001oti | 1904 | 4/27-8/15 | Dallas Giants | Texas League | , | |
| Otis Johnson | johnso001oti | 1904 | 9/6-9/24 | Little Rock Travelers | Southern Association | , | |
| Bill Johnston | johnst004wil | 1904 | Sharon PA | Independent | , | ||
| William Joihnson | 1904 | 5/24-6/26 | Binghamton Bingoes | New York State League | , | ||
| Jones | jones-132--- | 1904 | Sacramento | California State League | , | ||
| Jones | 1904 | 5/12 | Grand Rapids Orphans | Central League | , | ||
| Jones | 1904-06 | Yale University | College | , | |||
| Jones | 1904-06 | Gardiner ME | Independent | , | |||
| Alex Jones | jones-002ale | 1904 | 5/7-9/21 | Buffalo Bisons | Eastern League | , | |
| Alf Jones | jones-001alf | 1904 | 5/17-6/10+ | Chattanooga | Tennessee-Alabama League | , | |
| Bud Jones | jones-131--- | 1904 | 5/6-9/5 | Fort Dodge Gypsum Eaters | Iowa League | , | |
| Burton Jones | jones-002bur | 1904 | 9 g. | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |
| Charles Jones | jones-003w-- | 1904 | 5/3-8/4 | Beaumont Millionaires | South Texas League | , | |
| Charlie Jones | jones-005cha | 1904 | 5/10-9/20 | St. Paul Saints | American Association | , | |
| Charlie Jones | jones-005cha | 1904 | 5 g. | Chicago | American League | Chicago, IL | |
| Cowboy Jones | jones-003alb | 1904 | 55 g. | San Francisco Seals | Pacific Coast League | , | |
| Cowboy Jones | jones-003alb | 1904 | Oakland Oaks | Pacific Coast League | , | ||
| D. W. Jones | jones-002d-- | 1904 | 28 ab | Natchez Indians | Cotton States League | , | |
| Daniel Jones | jones-003dan | 1904 | 47 g. | Canton | Delta League | , | |
| Davy Jones | jones-005dav | 1904 | Chicago | National League | Chicago, IL | ||
| Doc Jones | jones-003w-- | 1904 | +6/7+ | Beaumont Millionaires | South Texas League | , | |
| Elijah Jones | jones-001eli | 1904 | Detr.- | Independent | , | ||
| Ernie Jones | jones-002ern | 1904 | Guthrie Blues | Southwestern League | , | ||
| Isom Jones | jones-001iso | 1904 | no g. | Little Rock Travelers | Southern Association | , | |
| Isom Jones | jones-001iso | 1904 | 35 g. | Jackson Senators | Delta League | , | |
| Jim Jones | jones-022jam | 1904 | 5/6-9/28 | Newark Sailors | Eastern League | , | |
| Ross Jones | jones-003ros | 1904 | Springfield Hustlers | Illinois-Indiana-Iowa League | , | ||
| Ross Jones | jones-003ros | 1904 | 16 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| Tom Jones | jones-002tho | 1904 | St. Louis | American League | St. Louis, MO | ||
| Wallace Jones | jones-001wal | 1904 | Kingston Colonials | Hudson River League | , | ||
| William Jones | jones-021wil | 1904 | 96 g. | Fort Scott Giants | Missouri Valley League | , | |
| Harry Jope | jope--001hen | 1904 | 84 g. | New Haven Blues | Connecticut State League | , | |
| Jordan | jordan017--- | 1904 | 5/12-5/22+ | Burlington River Rats | Iowa League | , | |
| Bert Jordan | 1904 | Bridgeport HS | High School | , | |||
| Bert Jordan | 1904 | Haverhill Hustlers | New England League | , | |||
| Charlie Jordan | jordan003cha | 1904 | 5/3- | Lawrence Colts | New England League | , | |
| Charlie Jordan | jordan003cha | 1904 | Manchester | New England League | , | ||
| Charlie Jordan | jordan003cha | 1904 | -8/30 | Concord Marines | New England League | , | |
| Dutch Jordan | jordan001ado | 1904 | - 10/8 | 87 g. | Brooklyn | National League | Brooklyn, NY |
| Slats Jordan | jordan001cla | 1904 | Lancaster PA | Independent | , | ||
| Tim Jordan | jordan002tim | 1904 | 4/29-9/28 | Baltimore Orioles | Eastern League | , | |
| Jordon | 1904 | 3 g. | Warren OH | Independent | , | ||
| George Josslyn | jossly001geo | 1904 | 4/30-9/17 | New Bedford Whalers | New England League | , | |
| Michael Joyce | joyce-002mic | 1904 | 4/29-9/28 | Montreal Royals | Eastern League | , | |
| Frank Jude | jude--001fra | 1904 | Carlisle Indian | College | , | ||
| Frank Jude | jude--001fra | 1904 | Carlisle PA | Independent | , | ||
| Edward Justice | justic001edw | 1904 | 61 g. | Newark OH | Independent | , | |
| Walt Justis | justis001wal | 1904 | Lawrenburg | Independent | , | ||
| Gustav Jutzi | jutzi-001joh | 1904 | +5/10+ | Savannah Pathfinders | South Atlantic League | , | |
| Gustav Jutzi | jutzi-001joh | 1904 | 3 g. | Piqua OH | Independent | , | |
| Gustav Jutzi | jutzi-001joh | 1904 | Lima OH | Independent | , | ||
| Ed Kaffenburg | 1904 | Lansingburg | Indiana State League | , | |||
| Nick Kahl | kahl--001nic | 1904 | 4/24-9/25 | Colorado Springs Millionaires | Western League | , | |
| Mike Kahoe | kahoe-001mic | 1904 | 72 g. | St. Louis | American League | St. Louis, MO | |
| Charles Kain | kain--001cha | 1904 | 4/28-8/16 | Evansville River Rats | Central League | , | |
| Nicholas Kaiser | kaiser001nic | 1904 | +8/19+ | Calumet Aristocrats | Copper Country League | , | |
| John Kalahan | kalaha001joh | 1904 | 5/17-6/6 | Nashua | New England League | , | |
| Herman Kalkenback | kalten001h-- | 1904 | 6/18-6/26+ | Fargo | Northern League | , | |
| George Kalkhoff | kalkho002geo | 1904 | Baton Rouge Red Sticks | Cotton States League | , | ||
| Ambrose Kane | kane--001amb | 1904 | 4/30-9/17 | Concord Marines | New England League | , | |
| Harry Kane | kane--001har | 1904 | 5/1-6/11 | Rochester Bronchos | Eastern League | , | |
| Harry Kane | kane--001har | 1904 | 39 g. | Clarksdale | Delta League | , | |
| Harry Kane | kane--001har | 1904 | 9/5-9/17 | Memphis Egyptians | Southern Association | , | |
| Jerry Kane | kane--001jer | 1904 | 120 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| Jerry Kane | kane--001jer | 1904 | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | ||
| John Kane | kane--002joh | 1904 | 120 g. | Pittsburg Coal Diggers | Missouri Valley League | , | |
| John Kane | kane--004fra | 1904 | Holyoke Paperweights | Connecticut State League | , | ||
| John Kane | kane--004fra | 1904 | Plattsburgh | Northern New York League | , | ||
| Louis Kane | kane--000lou | 1904 | +7/3+ | Butte MT | Independent | , | |
| Stephen Kane | 1904 | Umpire | Central League | , | |||
| Jay Kanzler | kanzle001jay | 1904 | 457 ab | Monroe Hill Citys | Cotton States League | , | |
| Elias Kaphan | kaphan001eli | 1904 | 113 g. | Galveston Sand Crabs | South Texas League | , | |
| Elias Kaphan | kaphan001eli | 1904 | 9/23-9/24 | Shreveport Pirates | Southern Association | , | |
| Charles Karnell | karnel001cha | 1904 | Fort Wayne Railroaders | Central League | , | ||
| William Karney | karney001wil | 1904 | 5/16-6/30+ | Chattanooga | Tennessee-Alabama League | , | |
| William Karney | karney001wil | 1904 | 7/- | Bessemer | Tennessee-Alabama League | , | |
| Bill Karns | karns-001wil | 1904 | 5/2-5/7 | Providence Grays | Eastern League | , | |
| Bill Karns | karns-001wil | 1904 | Hartford Senators | Connecticut State League | , | ||
| Henry Karsten | karste001hen | 1904 | 5/16-5/24 | Grand Rapids Orphans | Central League | , | |
| Jack Katoll | katoll001joh | 1904 | 4/20-5/22 | Minneapolis Millers | American Association | , | |
| John Keady | keady-001j-- | 1904 | Dartmouth | College | , | ||
| William Keane | keane-002wil | 1904 | 91 g. | New London Whalers | Connecticut State League | , | |
| William Keane | 1904 | +5/29+ | Georgetown U. | College | , | ||
| George Keas | keas--001geo | 1904 | 5/19-6/11+ | Superior Longshoremen | Northern League | , | |
| George Keas | keas--001geo | 1904 | +6/27-6/29+ | Oskaloosa Quakers | Iowa League | , | |
| Michael Keaton | keaton001mic | 1904 | 11 g. | Columbia Skyscrapers | South Atlantic League | , | |
| Keefe | keefe-006--- | 1904 | 131 ab | Natchez Indians | Cotton States League | , | |
| Keefe | keefe-008--- | 1904 | 6/30-7/14 | Troy Trojans | New York State League | , | |
| Bobby Keefe | keefe-001rob | 1904 | 58 g. | Tacoma Tigers | Pacific Coast League | , | |
| John Keefe | 1904 | 4/24-9/25 | Umpire | Western League | , | ||
| Thomas Keeler | keeler002--- | 1904 | Poseyville IN | Independent | , | ||
| Joe Keenan | keenan001jos | 1904 | 4/23-9/24 | Memphis Egyptians | Southern Association | , | |
| John Kehoe | kehoe-001joh | 1904 | 4/30-9/15 | New Bedford Whalers | New England League | , | |
| Bill Keister | keiste001wil | 1904 | 4/29-9/28 | Jersey City Skeeters | Eastern League | , | |
| George Kelb | kelb--002geo | 1904 | 5/1-6/22 | Beaumont Millionaires | South Texas League | , | |
| George Kelb | kelb--002geo | 1904 | Natchez Indians | Cotton States League | , | ||
| Charles Kelcher | 1904 | Lebanon | Tri-State League | , | |||
| Hugh Kellackey | kellac001hug | 1904 | 4/28-5/12 | Salt Lake City Elders | Pacific National League | , | |
| Hugh Kellackey | kellac001hug | 1904 | 6/4-9/25 | Boise Fruit Pickers | Pacific National League | , | |
| Hugh Kellackey | kellac001hug | 1904 | +11/6+ | Portland Browns | Pacific Coast League | , | |
| James Keller | keller001jam | 1904 | 29 g. | Topeka Saints | Missouri Valley League | , | |
| Kelley | kelley030--- | 1904 | Kingston Colonials | Hudson River League | , | ||
| Kelley | kelley025--- | 1904 | 59 g. | Brookhaven | Delta League | , | |
| Kelley | kelley048--- | 1904 | 7/16-7/18 | St. Joseph Saints | Western League | , | |
| Bill Kelley | kelley006wil | 1904 | 5/19- | 69 g. | Winnipeg Maroons | Northern League | , |
| Bill Kelley | kelley006wil | 1904 | Terre Haute Hottentots | Central League | , | ||
| H. A. Kelley | 1904 | 413 ab | Greenville Cotton Pickers | Cotton States League | , | ||
| James Kelley | kelley009jam | 1904 | 5/5- | Concord Marines | New England League | , | |
| James Kelley | kelley009jam | 1904 | -5/17 | Lawrence Colts | New England League | , | |
| Joe Kelley | kelley002jos | 1904 | Cincinnati | National League | Cincinnati, OH | ||
| Mike Kelley | kelley002mic | 1904 | 4/20-9/3 | St. Paul Saints | American Association | , | |
| Willis Kelley | kelley007wil | 1904 | San Jose | California State League | , | ||
| Al Kellogg | kellog001alb | 1904 | 9/4-9/21 | Providence Grays | Eastern League | , | |
| Win Kellum | kellum001win | 1904 | 36 g. | Cincinnati | National League | Cincinnati, OH | |
| Kelly | kelly-123--- | 1904 | 6/18-6/23 | Providence Grays | Eastern League | , | |
| Kelly | kelly-123--- | 1904 | 8/27-9/5 | Providence Grays | Eastern League | , | |
| Billy Kelly | kelly-006wil | 1904 | 4/24-9/25 | Sioux City Soos | Western League | , | |
| George Kelly | kelly-005geo | 1904 | 4/-7/11 | Jacksonville Jays | South Atlantic League | , | |
| George Kelly | kelly-005geo | 1904 | 33 g. | Savannah Pathfinders | South Atlantic League | , | |
| George Kelly | kelly-005geo | 1904 | Augusta Tourists | South Atlantic League | , | ||
| George Kelly | kelly-005geo | 1904 | Umpire | South Atlantic League | , | ||
| James Kelly | kelly-002jam | 1904 | 149 g. | Hudson Marines | Hudson River League | , | |
| John Kelly | 1904 | Umpire | Connecticut State League | , | |||
| John Kelly | 1904 | 6/10-9/25 | Umpire | Western League | , | ||
| John Kelly | kelly-003joh | 1904 | 4/29-9/28 | Baltimore Orioles | Eastern League | , | |
| M. Kelly | kelly-001m-- | 1904 | 9/6-9/28 | Montreal Royals | Eastern League | , | |
| Thomas Kelly | kelly-001tho | 1904 | Lodi | California State League | , | ||
| Thomas Kelly | 1904 | 4/29-9/28 | Umpire | Eastern League | , | ||
| W. A. Kelly | 1904 | Nashua | New England League | , | |||
| Bill Kemmer | kemmer001wil | 1904 | 4/24-8/6 | St. Joseph Saints | Western League | , | |
| Bill Kemmer | kemmer001wil | 1904 | 8/21-9/12 | Toledo Mud Hens | American Association | , | |
| Ed Keniston | kenist000ed- | 1904 | 5/4-5/6 | Fall River Indians | New England League | , | |
| Ed Kenna | kenna-004edw | 1904 | 4/26-9/25 | Denver Grizzlies | Western League | , | |
| Kennedy | kenned035--- | 1904 | Oakland | California State League | , | ||
| Albert Kennedy | kenned002alb | 1904 | 5/6-9/5 | Ottumwa Standpatters | Iowa League | , | |
| Brickyard Kennedy | kenned005wil | 1904 | +5/11+ | Piqua OH | Independent | , | |
| Brickyard Kennedy | kenned005wil | 1904 | 7/31-9/12 | Wheeling Stogies | Central League | , | |
| Charles Kennedy | kenned001cha | 1904 | Umpire | Connecticut State League | , | ||
| James Kennedy | kenned006jam | 1904 | 54 g. | Savannah Pathfinders | South Atlantic League | , | |
| James Kennedy | kenned006jam | 1904 | 9/8-9/28 | Rochester Bronchos | Eastern League | , | |
| John Kennedy | kenned009joh | 1904 | 6/29-7/14+ | Elmira | Southern Tier League | , | |
| John Kennedy | kenned009joh | 1904 | 8/11-8/19 | Hornellsville Maple Cities | Southern Tier League | , | |
| John Kennedy | kenned009joh | 1904 | 8/31-9/22 | Rochester Bronchos | Eastern League | , | |
| John Kennedy | 1904 | no g. | Montreal Royals | Eastern League | , | ||
| Robert Kennedy | kenned004rob | 1904 | 4/26-4/28 | Atlanta Crackers | Southern Association | , | |
| Robert Kennedy | kenned004rob | 1904 | 96 g. | Savannah Pathfinders | South Atlantic League | , | |
| Robert Kennedy | kenned004rob | 1904 | Columbia Skyscrapers | South Atlantic League | , | ||
| Sam Kennedy | kenned001sam | 1904 | Meriden Silverites | Connecticut State League | , | ||
| Sherman Kennedy | kenned001she | 1904 | 4/21-9/17 | Nashville Volunteers | Southern Association | , | |
| William Kennelly | kennel001w-- | 1904 | Pine Bluff Lumbermen | Cotton States League | , | ||
| William Kennelly | kennel002wil | 1904 | Duluth White Sox | Northern League | , | ||
| William Kennoy | kennoy001wil | 1904 | , | ||||
| William Kennoy | kennoy001wil | 1904 | Pitt.-Collegians | Independent | , | ||
| William Kennoy | kennoy001wil | 1904 | Waynesburg PA | Independent | , | ||
| Taylor Kensel | kensel001tay | 1904 | 5/6-9/5 | Oskaloosa Quakers | Iowa League | , | |
| Maurice Kent | 1904-07 | Univ. of Iowa | College | , | |||
| John Kerin | kerin-001joh | 1904 | 4/30-9/17 | Umpire | New England League | , | |
| John Kerins | kerins001joh | 1904 | Umpire | New England League | , | ||
| Aaron F. Kerr | kerr--001aar | 1904 | Sharon PA | Independent | , | ||
| Otto Kersten | kerste000ott | 1904 | +8/20+ | Forsyth MO | Independent | , | |
| Kerwin | kerwin007--- | 1904 | 7/1 | Hornellsville Maple Cities | Southern Tier League | , | |
| Dan Kerwin | kerwin001dan | 1904 | 4/20-9/19 | Louisville Colonels | American Association | , | |
| Fred Ketchum | ketchu001fre | 1904 | 4/24-9/25 | Denver Grizzlies | Western League | , | |
| Philip Ketter | ketter001phi | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | ||
| George Keyes | keyes-001geo | 1904 | 105 g. | Bridgeport Orators | Connecticut State League | , | |
| George Keyes | keyes-001geo | 1904 | Meriden Silverites | Connecticut State League | , | ||
| Buck Kieb | kieb--000buc | 1904 | 7/8-8/19 | Wellsville Oil Drillers | Southern Tier League | , | |
| Adam? Kiefer | 1904 | Umpire | Central League | , | |||
| John Kiernan | kierna001joh | 1904 | 5/6-5/18 | Albany Senators | New York State League | , | |
| John Kiernan | kierna001joh | 1904 | 7/7-9/19 | New Bedford Whalers | New England League | , | |
| Tom Kiernan | kierna001tho | 1904 | 156 ab | Natchez Indians | Cotton States League | , | |
| George Kihm | kihm--001geo | 1904 | 4/20-9/20 | Columbus Senators | American Association | , | |
| Frank Killen | killen002fra | 1904 | 7/23-9/6 | Umpire | American Association | , | |
| Frank Killen | killen001fra | 1904 | Johnstown Johnnies | Pennsylvania League | , | ||
| Ed Killian | killia001edw | 1904 | 40 g. | Detroit | American League | Detroit, MI | |
| John Killian | killia001joh | 1904 | +7/31-9/5 | Burlington River Rats | Iowa League | , | |
| Sid Killian | killia001sid | 1904 | Rockford Red Sox | Illinois-Indiana-Iowa League | , | ||
| John Killilay | killil001joh | 1904 | 14 g. | Leavenworth Orioles | Missouri Valley League | , | |
| John Killilay | killil001joh | 1904 | Iola Gasbags | Missouri Valley League | , | ||
| John Killilay | killil001joh | 1904 | 14 g. | Leavenworth Orioles | Missouri Valley League | , | |
| Kilmer | kilmer000--- | 1904 | 7/4-7/7 | Penn Yan Grape Pickers | Southern Tier League | , | |
| Peter Kilroy | kilroy001orv | 1904 | 5/19-7/25 | Superior Longshoremen | Northern League | , | |
| Peter Kilroy | kilroy001orv | 1904 | 7/30-9/5 | Waterloo Microbes | Iowa League | , | |
| Peter Kilroy | kilroy001orv | 1904 | 9/9-9/20 | St. Paul Saints | American Association | , | |
| John Kimble | kimbal002joh | 1904 | 6/28 | Lawrence Colts | New England League | , | |
| King | king--031--- | 1904 | 5/16-5/27+ | Bessemer | Tennessee-Alabama League | , | |
| Frank King | king--004fra | 1904 | 5/3-6/17 | Camden | Tri-State League | , | |
| Frank King | king--004fra | 1904 | Atlantic City NJ | Independent | , | ||
| Frank King | king--004fra | 1904 | 43 g. | Savannah Pathfinders | South Atlantic League | , | |
| Husky King | king--002h-- | 1904 | 413 ab | Greenville Cotton Pickers | Cotton States League | , | |
| Victor King | king--001vic | 1904 | Davenport River Rats | Illinois-Indiana-Iowa League | , | ||
| Billy Kinloch | kinloc001bil | 1904 | , | ||||
| Ed Kinsella | kinsel001edw | 1904 | 23 g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| William Kinskey | kinske000wil | 1904 | 8/8 | Montreal Royals | Eastern League | , | |
| Ed Kippert | kipper002edw | 1904 | +6/15-8/31+ | Dollar Bay | Copper Country League | , | |
| Enos Kirkpatrick | 1904 | Duquesne Univ. | College | , | |||
| William Kirwan | kirwan001wil | 1904 | +7/8+ | Jacksonville Jays | South Atlantic League | , | |
| William Kirwan | kirwan001wil | 1904 | +8/14+ | Austin PA | Independent | , | |
| Rube Kisinger | kising001cha | 1904 | 5/2-9/23 | Buffalo Bisons | Eastern League | , | |
| Frank Kitson | kitson001fra | 1904 | 27 g. | Detroit | American League | Detroit, MI | |
| Charles Kittinger | 1904 | 11 g. | Akron OH | Independent | , | ||
| Malachi Kittridge | kittri001mal | 1904 | 81 g. | Washington | American League | Washington, DC | |
| Red Kleinow | kleino001joh | 1904 | New York | American League | New York, NY | ||
| William Klem | klem--001bil | 1904 | 6/3-9/19 | Umpire | American Association | , | |
| John Klier | klier-001joh | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | ||
| Kline | 1904 | 6/29 | Wheeling Stogies | Central League | , | ||
| George Kline | kline-009--- | 1904 | +5/10+ | Leavenworth Orioles | Missouri Valley League | , | |
| John Kline | kline-001joh | 1904 | Columbia Skyscrapers | South Atlantic League | , | ||
| John Kline | kline-001joh | 1904 | Jackson Senators | Delta League | , | ||
| Louis Kline | kline-001l-- | 1904 | 8/2-8/4 | Grand Forks Forkers | Northern League | , | |
| Rudy Kling | kling-001rud | 1904 | 56 ab | Monroe Hill Citys | Cotton States League | , | |
| John Klinger | klinge005--- | 1904 | 8/11-9/6 | Evansville River Rats | Central League | , | |
| William Klintworth | klintw001wil | 1904 | 4/30-5/9 | Wheeling Stogies | Central League | , | |
| Fred Klobedanz | klobed001fre | 1904 | 4/30-9/17 | Lawrence Colts | New England League | , | |
| William Klock | klock-001wil | 1904 | 5/8-5/18 | Ilion Typewriters | New York State League | , | |
| William Klock | klock-001wil | 1904 | 5/28-7/14 | Binghamton Bingoes | New York State League | , | |
| Gus Klopf | klopf-001gus | 1904 | , | ||||
| O. Knapp | knapp-008--- | 1904 | 5/8-9/4 | Aberdeen Pippins | Southwest Washington League | , | |
| Louis Knau | knau--001lou | 1904 | 4/30-9/16 | Manchester | New England League | , | |
| Phil Knell | knell-001phi | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| Charlie Knepper | kneppe002cha | 1904 | 25 g. | Warren OH | Independent | , | |
| Julius Knoll | knoll-001jul | 1904 | 5/3-5/22 | Toledo Mud Hens | American Association | , | |
| Julius Knoll | knoll-001jul | 1904 | 5/29-9/4 | Dayton Veterans | Central League | , | |
| Punch Knoll | knoll-001cha | 1904 | U. of Nashville | College | , | ||
| Punch Knoll | knoll-001cha | 1904 | 4/21-9/24 | Nashville Volunteers | Southern Association | , | |
| Joe Knotts | knotts002jos | 1904 | Chester | Pennsylvania League | , | ||
| Joe Knotts | knotts002jos | 1904 | 7/14 | Lebanon | Tri-State League | , | |
| Joe Knotts | knotts002jos | 1904 | 8/13 | Wilmington Peaches | Tri-State League | , | |
| Dick Knox | knox--002ric | 1904 | 4/28-9/6 | Evansville River Rats | Central League | , | |
| George Kockill | 1904 | , | |||||
| Ben Koehler | koehle001ber | 1904 | Vicksburg Hill Billies | Cotton States League | , | ||
| Ben Koehler | koehle001ber | 1904 | 5 ab | Natchez Indians | Cotton States League | , | |
| Ben Koehler | koehle001ber | 1904 | 4/21-9/24 | Atlanta Crackers | Southern Association | , | |
| Koelin | koelin000--- | 1904 | , | ||||
| Steve Kohlar | kohlar001ste | 1904 | 17 g. | Galveston Sand Crabs | South Texas League | , | |
| Steve Kohlar | kohlar001ste | 1904 | 46 g. | Charleston Sea Gulls | South Atlantic League | , | |
| Steve Kohlar | kohlar001ste | 1904 | Augusta Tourists | South Atlantic League | , | ||
| Henry Kohler | 1904 | Springfield Midgets | Missouri Valley League | , | |||
| Henry Kohler | 1904 | StL.-Kerns | St. Louis Trolley League | , | |||
| Henry Kohler | 1904 | +8/21+ | St.L-Cahills | Independent | , | ||
| Steve Kolar/Kohlar | kohlar001ste | 1904 | 46 g. | Charleston Sea Gulls | South Atlantic League | , | |
| Steve Kolar/Kohlar | kohlar001ste | 1904 | Augusta Tourists | South Atlantic League | , | ||
| Steve Kolar/Kohlar | kohlar001ste | 1904 | 17 g. | Galveston Sand Crabs | South Texas League | , | |
| Eddie Kolb | kolb--001edd | 1904 | 26 g. | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | |
| William Kommer | kommer000bil | 1904 | 77 g. | Niles OH | Independent | , | |
| Erwin Kosche | kosche000erw | 1904 | Kewanee IL | Independent | , | ||
| Erwin Kosche | kosche000erw | 1904 | 7/14-7/15 | Grand Rapids Orphans | Central League | , | |
| Fred Kossuch | kossuc001fre | 1904 | +6/5+ | Detr.-Athletics | Independent | , | |
| Joe Kostal | kostal001jos | 1904 | 4/26-9/24 | Sioux City Soos | Western League | , | |
| Josef Koukalik | koukal001jos | 1904 | 5/20- | 17 g. | Duluth White Sox | Northern League | , |
| Josef Koukalik | koukal001jos | 1904 | 9/1 | Brooklyn | National League | Brooklyn, NY | |
| Kramer | 1904 | 6/8-6/11 | Grand Rapids Orphans | Central League | , | ||
| Kramer | 1904 | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |||
| Gabriel Kraufman | 1904 | Pittsburg Coal Diggers | Missouri Valley League | , | |||
| Charlie Krause | krause001cha | 1904 | 4/28-5/12 | Dayton Veterans | Central League | , | |
| Harry Krause | krause004har | 1904 | 5/17-5/24 | Montreal Royals | Eastern League | , | |
| Krebs | krebs-003--- | 1904 | 39 g. | Hattiesburg | Delta League | , | |
| Krebs | krebs-002c-- | 1904 | +6/5+ | Manhattan Col. | College | , | |
| Krebs | krebs-002c-- | 1904 | 7/12- | Addison White Sox | Southern Tier League | , | |
| Krebs | krebs-002c-- | 1904 | New Haven Blues | Connecticut State League | , | ||
| Ed Krebs | krebs-001edw | 1904 | 65 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| William Kreidy | kreidy001wil | 1904 | Newburgh Taylor-mades | Hudson River League | , | ||
| Edward Kreiger | kreige001edw | 1904 | 3 ab | Natchez Indians | Cotton States League | , | |
| Kribbs | kribbs000--- | 1904 | 7/20 | Hornellsville Maple Cities | Southern Tier League | , | |
| George Krick | krick-001geo | 1904 | +6/23-8/8+ | Burlington River Rats | Iowa League | , | |
| George Krick | krick-001geo | 1904 | +8/25-9/5 | Oskaloosa Quakers | Iowa League | , | |
| Anthony Krieder | kriedl001ant | 1904 | +8/4+ | Knoxville | Tennessee-Alabama League | , | |
| Anthony Krieder | kriedl001ant | 1904 | 3 g. | Knoxville | Tennessee-Alabama League | , | |
| John Kroell | kroell001joh | 1904 | Louisville CO | , | |||
| Krouse | 1904 | 5/14-5/20 | Grand Rapids Orphans | Central League | , | ||
| Ernest Krueger | kruege002ern | 1904 | +7/8+ | Muskegon Elks | Independent | , | |
| H. O. Krueger | kruege001h-- | 1904 | 113 g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| Hugo Krueger | kreuge000p-- | 1904 | 11 g. | Niles OH | Independent | , | |
| Otto Krueger | kruege002art | 1904 | 86 g. | Pittsburgh | National League | Pittsburgh, PA | |
| Henry Krug | krug--001hen | 1904 | San Francisco | California State League | , | ||
| Henry Krug | krug--001hen | 1904 | 7 g. | Portland Browns | Pacific Coast League | , | |
| Henry Krug | krug--001hen | 1904 | 4/21-9/20 | Atlanta Crackers | Southern Association | , | |
| Art Kruger | kruger001art | 1904 | 212 g. | Oakland Oaks | Pacific Coast League | , | |
| Harry Kubitz | kubitz001har | 1904 | 28 g. | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | |
| Kuehne | 1904 | 33 g. | Kane PA | Independent | , | ||
| Albert Kuhn | kuhn--001alb | 1904 | 120 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| Jimmy Kuhn | kuhn--001jam | 1904 | 99 g. | Columbia Skyscrapers | South Atlantic League | , | |
| Charlie Kuhns | kuhns-001cha | 1904 | 4/29-5/26 | Toronto Maple Leafs | Eastern League | , | |
| Charlie Kuhns | kuhns-001cha | 1904 | 6/1-8/15 | Rochester Bronchos | Eastern League | , | |
| Charlie Kuhns | kuhns-001cha | 1904 | +8/26-9/10 | Altoona Mountaineers | Tri-State League | , | |
| Arthur Kulms | 1904 | Musk.-DickBrinks | Independent | , | |||
| Kunkle | 1904 | +5/11+ | Butte Miners/Fruit Pickers | Pacific National League | , | ||
| Henry Kussmaul | kussma000hen | 1904 | 5/5 | Concord Marines | New England League | , | |
| W. C. Kyle | kyle--001w-- | 1904 | 5/16-8/16 | Knoxville | Tennessee-Alabama League | , | |
| Nick Laabs | laabs-001nic | 1904 | 17 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| George LaBelle | labell001geo | 1904 | Sault Ste. Marie | Independent | , | ||
| Hank Labelle | labell001hen | 1904 | 5/3-9/17 | Nashua | New England League | , | |
| George LaChance | lachan001geo | 1904 | 157 g. | Boston | American League | Boston, MA | |
| George Lackey | 1904 | 6/7-6/8 | Umpire | Texas League | , | ||
| Hi Ladd | ladd--001art | 1904 | 116 g. | Bridgeport Orators | Connecticut State League | , | |
| Hi Ladd | ladd--001art | 1904 | 9/12-9/18 | Fall River Indians | New England League | , | |
| Harry LaFrance | lafran001har | 1904 | Topeka Saints | Missouri Valley League | , | ||
| John Lagger | lagger001joh | 1904 | 5/19- | 27 g. | Duluth White Sox | Northern League | , |
| Paul LaGrave | lagrav001pau | 1904 | 4/30- | San Antonio Bronchos | South Texas League | , | |
| Paul LaGrave | lagrav001pau | 1904 | -9/2 | Galveston Sand Crabs | South Texas League | , | |
| James Laird | laird-001jam | 1904 | 5/18-6/25+ | Sheffield | Tennessee-Alabama League | , | |
| Frank Lakaff | lakaff001fra | 1904 | 31 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Fred Lake | lake--001fre | 1904 | 4/30-9/17 | Lowell Tigers | New England League | , | |
| Joseph? Lake | 1904 | 9/1-9/6 | Troy Trojans | New York State League | , | ||
| Lally | lally-004--- | 1904 | 85 ab | Baton Rouge Red Sticks | Cotton States League | , | |
| Lally | lally-004--- | 1904 | +5/27+ | Greenville Cotton Pickers | Cotton States League | , | |
| Lally | 1904 | 7/14-7/24 | Paris Parasites/Ardmore Territorians | Texas League | , | ||
| Lally | 1904 | 42 g. | Coshocton OH | Independent | , | ||
| Bud Lally | lally-001bud | 1904 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | ||
| Dan Lally | lally-001dan | 1904 | 4/20-5/20 | Minneapolis Millers | American Association | , | |
| Dan Lally | lally-001dan | 1904 | 4 g. | Crookston Crooks | Northern League | , | |
| Dan Lally | lally-001dan | 1904 | 2 g. | Portland Browns | Pacific Coast League | , | |
| Dan Lally | lally-001dan | 1904 | 6/9- | 69 g. | Butte Miners/Fruit Pickers | Pacific National League | , |
| Harry Lally | lally-001har | 1904 | 80 g. | Clarksdale | Delta League | , | |
| Harry Lally | lally-001har | 1904 | Cairo Champions | Kentucky-Illinois-Tennessee League | , | ||
| Hugh Lally | lally-001hug | 1904 | 70 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Hugh Lally | lally-001hug | 1904 | +8/11+ | Fort Dodge Gypsum Eaters | Iowa League | , | |
| Hugh Lally | lally-001hug | 1904 | +8/20-9/5 | Boone Coal Miners | Iowa League | , | |
| Lewis LaLonge | kommer000bil | 1904 | 26 g. | Canton OH | Independent | , | |
| Pete Lamer | lamer-001pie | 1904 | Hoboken NJ | Independent | , | ||
| Claude Laming | laming001cla | 1904 | 76 g. | Topeka Saints | Missouri Valley League | , | |
| Grover Land | land--001gro | 1904 | 43+ g. | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| Alfred Landers | lander000alf | 1904 | GrFa-Mavericks | Independent | , | ||
| Ernest Landgraf | landgr001ern | 1904 | Houston Wanderers | South Texas League | , | ||
| Albert Landgraff | landgr002alb | 1904 | 121 ab | Natchez Indians | Cotton States League | , | |
| Albert Landgraff | landgr002alb | 1904 | 58 g. | Yazoo City Zoos | Delta League | , | |
| William Landy | landy-001wil | 1904 | Holyoke Paperweights | Connecticut State League | , | ||
| Ed Lane | lane--001ed- | 1904 | 5/15-7/8 | Anniston | Tennessee-Alabama League | , | |
| Sam Lanford | lanfor001lew | 1904-06 | Furman Univ. | College | , | ||
| Lang | lang--014--- | 1904 | 5/3-5/13 | Wilmington Peaches | Tri-State League | , | |
| Lang | lang--014--- | 1904 | no g. | Baltimore Orioles | Eastern League | , | |
| Lang | lang--014--- | 1904 | Sharon PA | Independent | , | ||
| John Lang | 1904 | Utica Pent-Ups | New York State League | , | |||
| John Lang | 1904 | 5/14-8/1 | Dayton Veterans | Central League | , | ||
| Lang/Long | 1904 | 7/11- | Wellsville Oil Drillers | Southern Tier League | , | ||
| Nig Langdon | langdo001fra | 1904 | +8/28+ | Pana IL | Independent | , | |
| Arthur Lange | lange-001art | 1904 | 17 g. | Dayton Veterans | Central League | , | |
| Robert Langley | langle001rob | 1904 | Stockton | California State League | , | ||
| John Lanham | lanham001j-- | 1904 | 5/16-8/3 | Knoxville | Tennessee-Alabama League | , | |
| Frank LaPorte | laport002fra | 1904 | 4/30-9/28 | Buffalo Bisons | Eastern League | , | |
| Patrick Larkin | larkin001p-- | 1904 | Georgetown U. | College | , | ||
| Patrick Larkin | larkin001p-- | 1904 | 6/29-8/12 | Penn Yan Grape Pickers | Southern Tier League | , | |
| Teddy Larkin | larkin001pie | 1904 | Meriden Silverites | Connecticut State League | , | ||
| William Larkin | larkin002wil | 1904 | 2 g. | Bridgeport Orators | Connecticut State League | , | |
| Sam LaRocque | larocq001sam | 1904 | 113 g. | Savannah Pathfinders | South Atlantic League | , | |
| Sam LaRocque | larocq001sam | 1904 | Charleston Sea Gulls | South Atlantic League | , | ||
| Benjamin Larrabee | larrab001ben | 1904 | 5/3-9/17 | Nashua | New England League | , | |
| Andrew Larsen | larsen004and | 1904 | 51+ g. | Cairo Champions | Kentucky-Illinois-Tennessee League | , | |
| Purl LaRue | 1904 | FtWa-Shamrocks | Independent | , | |||
| Arlie Latham | latham002wal | 1904 | 4/21-9/25 | Umpire | Southern Association | , | |
| Dick Latham | latham001ric | 1904 | 130 g. | Galveston Sand Crabs | South Texas League | , | |
| Tacks Latimer | latime001cli | 1904 | 111 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Tacks Latimer | latime001cli | 1904 | 9/16-9/28 | Newark Sailors | Eastern League | , | |
| Michael Lattin | 1904 | +7/23+ | Maryland A C | Independent | , | ||
| Billy Lauder | lauder001wil | 1904 | Murray Hill | Independent | , | ||
| Billy Lauder | lauder001wil | 1904 | 8/- | Corning White Ponies | Southern Tier League | , | |
| A. A. Lauer | 1904 | Yazoo City Zoos | Delta League | , | |||
| Laughlin | laughl003--- | 1904 | 49 g. | Brookhaven | Delta League | , | |
| Eddie Laughlin | laughl000edd | 1904 | +7/14+ | St. Albans | Northern New York League | , | |
| John Laughlin | laughl001joh | 1904 | -9/5 | Dollar Bay | Copper Country League | , | |
| Bill Lauterborn | lauter001wil | 1904 | 5/6-9/18 | Syracuse Stars | New York State League | , | |
| Bill Lauterborn | lauter001wil | 1904 | 9/20- | 20 g. | Boston | National League | Boston, MA |
| Ed Lauzon | lauzon001edw | 1904 | 4/23-5/13 | Shreveport Pirates | Southern Association | , | |
| Ed Lauzon | lauzon001edw | 1904 | 202 ab | Pine Bluff Lumbermen | Cotton States League | , | |
| William Laval | laval-001wil | 1904 | Furman Col | College | , | ||
| William Laval | laval-001wil | 1904 | Spartanburg | Carolina Interstate League | , | ||
| Lavelle | lavell001--- | 1904 | Pottstown PA | Independent | , | ||
| Frank Law | law---001fra | 1904 | 5/8-9/4 | Hoquiam Perfect Gentlemen | Southwest Washington League | , | |
| Jack Law | law---001joh | 1904 | 5/10-9/16 | Memphis Egyptians | Southern Association | , | |
| Ed Lawler | lawler001ed- | 1904 | 7/16-7/18 | Omaha Rangers | Western League | , | |
| Jack Lawler | lawler003joh | 1904 | 4/20-5/17 | St. Paul Saints | American Association | , | |
| Jack Lawler | lawler003joh | 1904 | 5/21-9/25 | Sioux City Soos | Western League | , | |
| John Lawler | lawler001joh | 1904 | 1 g. | Huntsville | Tennessee-Alabama League | , | |
| Ed Lawlor | lawlor001ed- | 1904 | 9/5-9/19 | Sioux City Soos | Western League | , | |
| Jack Lawlor | lawlor001joh | 1904 | 5/9-9/18 | Utica Pent-Ups | New York State League | , | |
| Lawrence | lawren042--- | 1904 | 5/15-7/24 | Olympia Senators | Southwest Washington League | , | |
| Andy Lawrence | lawren001and | 1904 | +7/14-8/24+ | Burlington | Northern New York League | , | |
| Mike Lawrence | lawren001mic | 1904 | 4/28-5/29 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Mike Lawrence | lawren001mic | 1904 | 5/30-7/30 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Mike Lawrence | lawren001mic | 1904 | 7/31-9/9 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Billy Lawson | lawson001wil | 1904 | Paterson Intruders | Hudson River League | , | ||
| Allen? Lawton | lawton004--- | 1904 | 6/29-8/1 | Penn Yan Grape Pickers | Southern Tier League | , | |
| Lawrence Lawton | lawton000al- | 1904 | 8/9-8/30 | Rochester Bronchos | Eastern League | , | |
| Benjamin Leach | 1904 | +8/28+ | Bonner MT | Independent | , | ||
| Hugh Leach | leach-001hug | 1904 | U. of Minnesota | College | , | ||
| Hugh Leach | leach-001hug | 1904 | +6/10- | 44 g. | Superior Longshoremen | Northern League | , |
| Samuel Leach | leach-000sam | 1904 | +8/28+ | Bonner MT | Independent | , | |
| David Leahy | leahy-001dav | 1904 | 5/6-9/17 | Lawrence Colts | New England League | , | |
| Tom Leahy | leahy-002tho | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| Tom Leahy | leahy-002tho | 1904 | Seattle Siwashes | Pacific Coast League | , | ||
| Frank Leary | leary-001fra | 1904 | 6/3-7/23 | Rochester Bronchos | Eastern League | , | |
| Frank Leary | leary-001fra | 1904 | 7/29-9/28 | Toronto Maple Leafs | Eastern League | , | |
| Sam Leatherby | 1904 | +5/14+ | Keokuk Indians | Iowa League | , | ||
| LeBarron | 1904 | 5/19-5/23+ | Winnipeg Maroons | Northern League | , | ||
| Emil Leber | leber-001emi | 1904 | Forest City | Clevland City League | , | ||
| William LeCompte | lecomp001w-- | 1904 | 53 ab | Pine Bluff Lumbermen | Cotton States League | , | |
| William LeCompte | lecomp001w-- | 1904 | 41 g. | Clarksdale | Delta League | , | |
| Carter Lee | lee---010car | 1904 | 4/28-5/15 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Carter Lee | lee---010car | 1904 | 5/18-5/30+ | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| George Lee | lee---001geo | 1904 | 5/3-9/13 | Concord Marines | New England League | , | |
| Granville Lee | lee---001gra | 1904 | 118 g. | Sedalia Goldbugs | Missouri Valley League | , | |
| Jack Lee | lee---003joh | 1904 | 4/25-6/29 | New Orleans Pelicans | Southern Association | , | |
| Jack Lee | lee---003joh | 1904 | 7/24-9/25 | Montgomery Senators | Southern Association | , | |
| William Lee | lee---016wil | 1904 | 6/28-9/8 | Fall River Indians | New England League | , | |
| Wyatt Lee | lee---001wya | 1904 | - 5/26 | 8 g. | Pittsburgh | National League | Pittsburgh, PA |
| Wyatt Lee | lee---001wya | 1904 | 6/16-9/19 | Toledo Mud Hens | American Association | , | |
| Reggie Leech | leech-000reg | 1904 | 6/29-8/12 | Penn Yan Grape Pickers | Southern Tier League | , | |
| Harry LeFrance | 1904 | no g. | Topeka Saints | Missouri Valley League | , | ||
| Leftwich | 1904 | 8/20 | Denton TX | Independent | , | ||
| Bill LeGrande | legran001w-- | 1904 | Bingham School | Academy | , | ||
| David Lehman | lehman001dav | 1904 | 42 g. | Charleston Sea Gulls | South Atlantic League | , | |
| Lehr | 1904 | Sioux City Soos | Western League | , | |||
| Ernest Leibfried | 1904 | 7/24- | Camden NJ | Independent | , | ||
| George Leidy | leidy-002geo | 1904 | 297 ab | Monroe Hill Citys | Cotton States League | , | |
| Lefty Leifield | leifie001alb | 1904 | 4/25-9/24 | Des Moines Prohibitionists | Western League | , | |
| Jim Leighton | leight001jam | 1904 | 297 ab | Monroe Hill Citys | Cotton States League | , | |
| Bill Leith | leith-001bil | 1904 | 5/2-9/17 | Manchester | New England League | , | |
| Harry Leitman | leitma001har | 1904 | , | ||||
| Sheldon Lejeune | lejeun001she | 1904 | +7/18+ | Missoula MT | Independent | , | |
| Lee Lemon | lemon-001lee | 1904 | 4/30-5/6 | Terre Haute Hottentots | Central League | , | |
| Lee Lemon | lemon-001lee | 1904 | 38+ g. | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | |
| Carl Lempke | lempke001car | 1904 | 5/9-5/10 | Colorado Springs Millionaires | Western League | , | |
| Carl Lempke | lempke001car | 1904 | 5/21- | 22 g. | Fargo | Northern League | , |
| Carl Lempke | lempke001car | 1904 | Cripple Creek CO | Independent | , | ||
| Ed Lennox | lennox001jam | 1904 | 5/3-6/7 | Camden | Tri-State League | , | |
| Ed Lennox | lennox001jam | 1904 | Brandywine PA | Independent | , | ||
| Lent | lent--003--- | 1904 | +5/29+ | Bellingham WA | Independent | , | |
| Frank Leonard | leonar001fra | 1904 | Lynn MA | Independent | , | ||
| John Leonard | leonar009joh | 1904 | 7/25-7/28 | New Bedford Whalers | New England League | , | |
| William Leonard | leonar011--- | 1904 | Independent | , | |||
| Pete LePine | lepine002lou | 1904 | 4/29-8/6 | Rochester Bronchos | Eastern League | , | |
| Pete LePine | lepine002lou | 1904 | 9/2 | Rochester Bronchos | Eastern League | , | |
| Louis LeRoy | leroy-001lou | 1904 | 6/2-9/22 | Montreal Royals | Eastern League | , | |
| Fenner Leslie | leslie001fen | 1904 | 4/20-8/4 | Minneapolis Millers | American Association | , | |
| Fenner Leslie | leslie001fen | 1904 | 8/27-9/25 | Sioux City Soos | Western League | , | |
| Tom Letcher | letche001tom | 1904 | 7/24-7/27 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Tom Letcher | letche001tom | 1904 | 8/3-9/6 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Sam Letherby | leathe001--- | 1904 | preseason | Omaha Rangers | Western League | , | |
| Sam Letherby | leathe001--- | 1904 | +5/10- | Keokuk Indians | Iowa League | , | |
| Rube Levy | levy--001reu | 1904 | Umpire | Pacific Coast League | , | ||
| Ed Lewee | lewee-001edw | 1904 | 4/27-9/20 | Kansas City Blues | American Association | , | |
| Lewis | lewis-061--- | 1904 | -6/16 | Huntsville | Tennessee-Alabama League | , | |
| Lewis | lewis-019--- | 1904 | 6/17- | Bessemer | Tennessee-Alabama League | , | |
| Lewis | lewis-034--- | 1904 | 1 g. | Sheffield | Tennessee-Alabama League | , | |
| B. Lewis | lewis-001b-- | 1904 | +8/10-8/20 | Chattanooga | Tennessee-Alabama League | , | |
| Carl Lewis | lewis-001car | 1904 | 4/28-5/15 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Carl Lewis | lewis-001car | 1904 | 5/18-6/3+ | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Carl Lewis | lewis-001car | 1904 | 6/12-6/15 | Spokane Indians | Pacific National League | , | |
| Carl Lewis | lewis-001car | 1904 | +7/4-7/24+ | Seattle Siwashes | Pacific Coast League | , | |
| Dudley Lewis | 1904 | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |||
| Dudley Lewis | 1904 | +7/3+ | Pine Bluff Lumbermen | Cotton States League | , | ||
| Dudley Lewis | 1904 | +7/28+ | Nashville TN | Independent | , | ||
| Earl Lewis | lewis-001ear | 1904 | 4/21-5/5 | Nashville Volunteers | Southern Association | , | |
| Earl Lewis | lewis-001ear | 1904 | 302 ab | Greenville Cotton Pickers | Cotton States League | , | |
| Earl Lewis | lewis-001ear | 1904 | 9/19-9/24 | Nashville Volunteers | Southern Association | , | |
| Gordon Lewis | lewis-001gor | 1904 | +6/12-6/27+ | Portage Lake | Copper Country League | , | |
| Gordon Lewis | lewis-001gor | 1904 | +8/21+ | Calumet Aristocrats | Copper Country League | , | |
| J. Fred Lewis | 1904 | 5/7-5/19 | Schenectady Electricians/Scranton Miners | New York State League | , | ||
| Joseph Lewis | 1904 | 5/22-7/25 | Pottstown PA | Independent | , | ||
| Phil Lewis | lewis-001phi | 1904 | 4/29-9/28 | Baltimore Orioles | Eastern League | , | |
| Richard Lewis | lewis-001ric | 1904 | 5/17-8/18 | Columbia | Tennessee-Alabama League | , | |
| Christie Lidders | lidder001--- | 1904 | RoIsl-Bennetts | Independent | , | ||
| Glenn Liebhardt | liebha002gle | 1904 | 4/24-5/31 | Omaha Rangers | Western League | , | |
| Glenn Liebhardt | liebha002gle | 1904 | 27 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Glenn Liebhardt | liebha002gle | 1904 | 9/25 | Omaha Rangers | Western League | , | |
| Lightfoot | lightf004--- | 1904 | +6/30+ | 2 g. | Bessemer | Tennessee-Alabama League | , |
| Lightfoot | lightf005--- | 1904 | 9/19 | Rochester Bronchos | Eastern League | , | |
| James Limric | limric001jam | 1904 | 5/4-5/20 | Buffalo Bisons | Eastern League | , | |
| James Limric | limric001jam | 1904 | 7/19 | Buffalo Bisons | Eastern League | , | |
| James Limric | limric001jam | 1904 | 7/24-8/19 | Hornellsville Maple Cities | Southern Tier League | , | |
| James Limric | limric001jam | 1904 | 8/9-9/27 | Rochester Bronchos | Eastern League | , | |
| Lind | 1904 | 5/27- | Urbana OH | Independent | , | ||
| Vive Lindaman | lindam001viv | 1904 | 4/25-9/25 | Sioux City Soos | Western League | , | |
| Bob Lindemann | lindem002joh | 1904 | 5/9-9/30 | Williamsport Millionaires | Tri-State League | , | |
| Ernie Lindemann | lindem001ern | 1904 | +9/18+ | Hoboken NJ | Independent | , | |
| Albert Linderbeck | linder001alb | 1904 | +7/7+ | Paulding OH | Independent | , | |
| Albert Linderbeck | linder001alb | 1904 | 16 g. | Grand Rapids Orphans | Central League | , | |
| Albert Linderbeck | linder001alb | 1904 | Paulding OH | Independent | , | ||
| Albert Linderbeck | linder001alb | 1904 | 7/18-7/19 | Fort Wayne Railroaders | Central League | , | |
| Albert Linderbeck | linder001alb | 1904 | 7/22-7/27 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Albert Linderbeck | linder001alb | 1904 | 7/28-8/14 | Grand Rapids Orphans | Central League | , | |
| Lindsay | 1904 | 13 g. | Akron OH | Independent | , | ||
| Lindsay | lindsa005--- | 1904 | +7/16-8/4+ | Chattanooga | Tennessee-Alabama League | , | |
| Harry Lindsay | lindsa001ira | 1904 | no g. | Ilion Typewriters | New York State League | , | |
| Harry Lindsay | lindsa001ira | 1904 | 5/6-7/22 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| John Lindsay | lindsa002joh | 1904 | 4/28-5/2 | Terre Haute Hottentots | Central League | , | |
| John Lindsay | lindsa002joh | 1904 | 5/4-9/11 | Fort Wayne Railroaders | Central League | , | |
| William Lindsay | 1904-06 | Guilford College | College | , | |||
| Harry Lindsey | lindsa001ira | 1904 | Ilion Typewriters | New York State League | , | ||
| Harry Lindsey | lindsa001ira | 1904 | 5/6-7/22 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Perry Lipe | lipe--001per | 1904 | 118 g. | Macon Highlanders | South Atlantic League | , | |
| Louis Lippert | lipper001lou | 1904 | 120 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Pete Lister | lister001mor | 1904 | 116 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| G. L. Livingston | 1904 | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |||
| Paddy Livingston | living001pat | 1904 | Albany Senators | New York State League | , | ||
| Paddy Livingston | living001pat | 1904 | 48 g. | Akron OH | Independent | , | |
| Jake Livingstone | living001jac | 1904 | Lebanon | Tri-State League | , | ||
| Jake Livingstone | living001jac | 1904 | Hoboken NJ | Independent | , | ||
| Abel Lizotte | lizott001abe | 1904 | 4/24-9/25 | St. Joseph Saints | Western League | , | |
| Arthur Lizzette | lizzet001art | 1904 | Sault Ste. Marie | Copper League | , | ||
| Edward Llewellyn | 1904 | 4/28- | Umpire | Central League | , | ||
| David LLoyd | lloyd-001dav | 1904 | Reading PA | Independent | , | ||
| Harry Lloyd | lloyd-002har | 1904 | 5/21 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| Hans Lobert | lobert001joh | 1904 | Johnstown PA | Independent | , | ||
| Hans Lobert | lobert001joh | 1904 | 4/24-9/25 | Des Moines Prohibitionists | Western League | , | |
| Frank Locke | locke-001fra | 1904 | New Haven Blues | Connecticut State League | , | ||
| Loderhose | loderh000--- | 1904 | 9/4 | St. Joseph Saints | Western League | , | |
| Frank Lofton | lofton001fra | 1904 | Columbus KS | Independent | , | ||
| Frank Lofton | lofton001fra | 1904 | Weir City Browns | Independent | , | ||
| Logan | logan-006--- | 1904 | 8/12-8/17 | Wellsville Oil Drillers | Southern Tier League | , | |
| David Logan | logan-001dav | 1904 | +5/25-8/20 | Huntsville | Tennessee-Alabama League | , | |
| Frank Logan | logan-001f-- | 1904 | 96 g. | Beaumont Millionaires | South Texas League | , | |
| Frank Logan | logan-001f-- | 1904 | San Antonio Bronchos | South Texas League | , | ||
| Tom Logan | logan-001tho | 1904 | 5/10-9/27 | York Penn Parks | Tri-State League | , | |
| Pete Lohman | lohman001geo | 1904 | Oakland Oaks | Pacific Coast League | , | ||
| Frank Lohr | lohr--001fra | 1904 | 4/24-5/28 | Sioux City Soos | Western League | , | |
| Frank Lohr | lohr--001fra | 1904 | 6/7-7/6 | Burlington River Rats | Iowa League | , | |
| Frank Lohr | lohr--001fra | 1904 | 7/8-9/5 | Waterloo Microbes | Iowa League | , | |
| Arthur Loker | loker-001--- | 1904 | g. ? | Sheffield | Tennessee-Alabama League | , | |
| Arthur Loker | loker-001--- | 1904 | Yazoo City Zoos | Delta League | , | ||
| Arthur Loker | loker-001--- | 1904 | Vicksburg Hill Billies | Cotton States League | , | ||
| Long | long--007--- | 1904 | Coatesville | Pennsylvania League | , | ||
| Long | long--062--- | 1904 | 6/22 | York Penn Parks | Tri-State League | , | |
| Bert Long | long--001ber | 1904 | 38 g. | Springfield Midgets | Missouri Valley League | , | |
| Frank Long | long--002fra | 1904 | 81 g. | Akron OH | Independent | , | |
| Harry Long | long--003har | 1904 | 44 g. | New London Whalers | Connecticut State League | , | |
| Herman Long | long--001her | 1904 | 4/20-6/21 | Toledo Mud Hens | American Association | , | |
| Herman Long | long--001her | 1904 | 7/13 | Philadelphia | National League | Philadelphia, PA | |
| James Long | long--001art | 1904 | Dayton Veterans | Central League | , | ||
| James Long | long--001art | 1904 | 5/11-5/20 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| James Long | long--001art | 1904 | Fowler IN | Independent | , | ||
| James Long | long--001art | 1904 | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | ||
| Red Long | long--001nel | 1904 | 5/3- | Lawrence Colts | New England League | , | |
| Red Long | long--001nel | 1904 | -8/16 | Haverhill Hustlers | New England League | , | |
| Red Long | long--001nel | 1904 | 8/23-9/18 | Utica Pent-Ups | New York State League | , | |
| Harry Longley | longle001har | 1904 | 4/27-7/26 | Corsicana Oil Citys | Texas League | , | |
| Harry Longley | longle001har | 1904 | 34 g. | Beaumont Millionaires | South Texas League | , | |
| Pete Loos | loos--001iva | 1904 | 5/10-6/7 | Lebanon | Tri-State League | , | |
| Bris Lord | lord--001bri | 1904 | Coatesville PA | Independent | , | ||
| Harry Lord | lord--001har | 1904 | Portland ME | Independent | , | ||
| William Lord | lord--001wil | 1904 | 5/3-5/13 | Wilmington Peaches | Tri-State League | , | |
| William Lord | lord--001wil | 1904 | Coatesville PA | Independent | , | ||
| Manfred Lothrop | 1904 | Rockville MA | Independent | , | |||
| Sylvester Loucks | loucks001syl | 1904 | 16 g. | Spokane Indians | Pacific National League | , | |
| Sylvester Loucks | loucks001syl | 1904 | Cordele GA | Independent | , | ||
| Sylvester Loucks | loucks001syl | 1904 | 8/10-8/20 | Huntsville | Tennessee-Alabama League | , | |
| Charlie Loudenslager | louden001cha | 1904 | 4/29-9/28 | Baltimore Orioles | Eastern League | , | |
| Charlie Loudenslager | louden001cha | 1904 | 4/15 | Brooklyn | National League | Brooklyn, NY | |
| Bert Lougheed | loughe001ber | 1904 | 4/29-7/4 | Salem Raglands | Oregon State League | , | |
| Bert Lougheed | loughe001ber | 1904 | 6/17 | Eugene Blues | Oregon State League | , | |
| James Loughmiller | loughm001--- | 1904 | +5/19+ | Shawnee Browns/Chickasha Indians | Southwestern League | , | |
| James Loughmiller | loughm001--- | 1904 | +6/24-9/5+ | Oklahoma City Mets | Southwestern League | , | |
| Love | love--006--- | 1904 | 12 g. | Springfield Midgets | Missouri Valley League | , | |
| Love | 1904 | Newburgh Taylor-mades | Hudson River League | , | |||
| Jackson Love | love--001jac | 1904 | Van Buren ARK | Independent | , | ||
| William Love | love--001bil | 1904 | +9/6+ | Batavia NY | Independent | , | |
| Clarence Lovell | lovell001cla | 1904 | 4/30-9/17 | Concord Marines | New England League | , | |
| Bobby Lowe | lowe--002rob | 1904 | Detroit | American League | Detroit, MI | ||
| George Lowell | lowell001geo | 1904 | 45 g. | Joplin Miners | Missouri Valley League | , | |
| John Lower | lower-001joh | 1904 | +6/7+ | Camden | Tri-State League | , | |
| Dennis Lowney | lowney001dan | 1904 | 4/21-9/24 | Nashville Volunteers | Southern Association | , | |
| Bill Luby | luby--001wil | 1904 | 31 g. | Springfield Ponies | Connecticut State League | , | |
| Charles Lucas | lucas-003cha | 1904 | 4/27-5/3 | Montgomery Senators | Southern Association | , | |
| Charles Lucas | lucas-003cha | 1904 | 63 g. | Augusta Tourists | South Atlantic League | , | |
| Harry Lucas | lucas-000buf | 1904 | 5/1-7/4 | Salem Raglands | Oregon State League | , | |
| James Lucas | lucas-001jam | 1904 | +5/11+ | Zanesville OH | ProtAssn | , | |
| William Lucas | lucas-005wil | 1904 | President | Pacific Northwest League | , | ||
| Fred Luchia | lucia-001fre | 1904 | 4/24-9/25 | Denver Grizzlies | Western League | , | |
| Con Lucid | lucid-001con | 1904 | Pine Bluff Lumbermen | Cotton States League | , | ||
| Bill Ludwig | ludwig002wil | 1904 | 108 g. | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |
| Herman Luettke | luettk001her | 1904 | Leavenworth Orioles | Missouri Valley League | , | ||
| George Lufkin | lufkin001geo | 1904 | 9/5- | Nashua | New England League | , | |
| George Lufkin | lufkin001geo | 1904 | -9/13 | Concord Marines | New England League | , | |
| Baldo Luitich | luitic001bal | 1904 | 4/30-7/13 | Galveston Sand Crabs | South Texas League | , | |
| Baldo Luitich | luitic001bal | 1904 | 7/24-9/11 | Beaumont Millionaires | South Texas League | , | |
| Harry Lumley | lumley001har | 1904 | 4/14- | 150 g. | Brooklyn | National League | Brooklyn, NY |
| Jack Lundbom | lundbo001joh | 1904 | 4/30-9/15 | Toledo Mud Hens | American Association | , | |
| Arthur Lundin | lundin001art | 1904 | 53 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Billy Lush | lush--001wil | 1904 | -10/8 | 138 g. | Cleveland | American League | Cleveland, OH |
| Johnny Lush | lush--001joh | 1904 | preseason | Williamsport Millionaires | Tri-State League | , | |
| Johnny Lush | lush--001joh | 1904 | 4/16- | 106 g. | Philadelphia | National League | Philadelphia, PA |
| Charlie Luskey | luskey001cha | 1904 | 4/22-6/2 | Atlanta Crackers | Southern Association | , | |
| Charlie Luskey | luskey001cha | 1904 | 8/25-8/26 | Harrisburg Senators | Tri-State League | , | |
| William Luyster | luyste001wil | 1904 | 5/1-6/3 | Montreal Royals | Eastern League | , | |
| William Luyster | luyste001wil | 1904 | 70 g. | Hartford Senators | Connecticut State League | , | |
| C. H. Lydsky | lydsky001c-- | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | ||
| Bob Lyman | lyman-001rob | 1904 | , | ||||
| Bobby Lynch | lynch-006rob | 1904 | 5/27-5/29 | Toronto Maple Leafs | Eastern League | , | |
| Bobby Lynch | lynch-006rob | 1904 | 6/2-6/3 | Rochester Bronchos | Eastern League | , | |
| Bobby Lynch | lynch-006rob | 1904 | 8/8-8/20 | Indianapolis Indians | American Association | , | |
| Ed Lynch | lynch-002edw | 1904 | 4/29-8/6 | Newark Sailors | Eastern League | , | |
| Ed Lynch | 1904 | Baton Rouge Red Sticks | Cotton States League | , | |||
| Edward Lynch | lynch-005edw | 1904 | 6/29-7/6 | Corning White Ponies | Southern Tier League | , | |
| Edward Lynch | lynch-005edw | 1904 | +8/14+ | Austin PA | Independent | , | |
| Edward Lynch | 1904 | Notre Dame | College | , | |||
| Henry Lynch | lynch-003hen | 1904 | 4/21-9/24 | Birmingham Barons | Southern Association | , | |
| Jack Lynch | lynch-009--- | 1904 | 5/16-5/24+ | Bessemer | Tennessee-Alabama League | , | |
| Joseph Lynch | lynch-001jos | 1904 | 45 g. | Fargo | Northern League | , | |
| Leigh Lynch | lynch-003hen | 1904 | Brown Univ. | College | , | ||
| Leigh Lynch | lynch-003hen | 1904 | no g. | New York | National League | New York, NY | |
| Leigh Lynch | lynch-003hen | 1904 | no g. | Birmingham Barons | Southern Association | , | |
| Leigh Lynch | lynch-003hen | 1904 | Meriden Silverites | Connecticut State League | , | ||
| Leigh Lynch | lynch-003hen | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| Michael Lynch | lynch-002mik | 1904 | St. John's Boston | Institue | , | ||
| Mike Lynch | lynch-003mic | 1904 | 219 g. | Tacoma Tigers | Pacific Coast League | , | |
| Mike Lynch | lynch-004mic | 1904 | 6/21- | 28 g. | Pittsburgh | National League | Pittsburgh, PA |
| Christopher Lynskey | lynsky001chr | 1904 | 6/4-8/20 | Huntsville | Tennessee-Alabama League | , | |
| Lyons | lyons-012--- | 1904 | +6/29-7/17 | Chattanooga | Tennessee-Alabama League | , | |
| Charles Lyons | lyons-003cha | 1904 | 114 g. | Leavenworth Orioles | Missouri Valley League | , | |
| Charles Lyons | lyons-001cha | 1904 | Davenport River Rats | Illinois-Indiana-Iowa League | , | ||
| Charles Lyons | lyons-001cha | 1904 | +5/30+ | Elwood IN | Independent | , | |
| Joseph Lyons | lyons-001jos | 1904 | Toledo Mud Hens | American Association | , | ||
| Sullivan Lyons | lyons-001sul | 1904 | 4/24-4/27 | Louisville Colonels | American Association | , | |
| Sullivan Lyons | lyons-001sul | 1904 | 17 g. | Clarksdale | Delta League | , | |
| Daniel Lytle | lytle-001dan | 1904 | Newburgh Taylor-mades | Hudson River League | , | ||
| Daniel Lytle | lytle-001dan | 1904 | 5/12-5/24 | Binghamton Bingoes | New York State League | , | |
| Charles Maag | maag--001c-- | 1904 | no g. | Little Rock Travelers | Southern Association | , | |
| Charles Maag | maag--001c-- | 1904 | 4/30-7/11 | Wheeling Stogies | Central League | , | |
| Charles Maag | maag--001c-- | 1904 | 54 g. | Arkon OH | Independent | , | |
| Harry Mace | mace--002har | 1904 | 4/26- | Umpire | South Atlantic League | , | |
| Bruce MacFarlane | macfar000bru | 1904 | 6/25-7/6 | Fall River Indians | New England League | , | |
| Ed MacGamwell | mcgamw002edw | 1904 | 5/6-9/17 | Albany Senators | New York State League | , | |
| Frank MacHale | mchale001fra | 1904 | no g. | Altoona Mountaineers | Tri-State League | , | |
| Frank MacHale | mchale001fra | 1904 | 8/2-9/23 | Williamsport Millionaires | Tri-State League | , | |
| Mack | mack--007--- | 1904 | 1 g. | Chattanooga | Tennessee-Alabama League | , | |
| Eugene? Mack | mack--030--- | 1904 | 5/17-9/6 | Lebanon | Tri-State League | , | |
| P. J. Mack | 1904 | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |||
| William Mack | mack--001wil | 1904 | 7/19-7/22 | Shreveport Pirates | Southern Association | , | |
| William Mack | mack--001wil | 1904 | 8/12-8/25 | St. Joseph Saints | Western League | , | |
| William Mack | mack--003wil | 1904 | 6/29-8/10 | Elmira | Southern Tier League | , | |
| William Mack | mack--003wil | 1904 | Austin PA | Independent | , | ||
| Ed Mackey | mackey001a-- | 1904 | 4/29-5/20 | Umpire | Texas League | , | |
| Ed Mackey | mackey001a-- | 1904 | +6/26+ | Umpire | South Texas League | , | |
| John Mackey | mackey004--- | 1904 | 5/8-5/23 | Bellingham WA | Independent | , | |
| John Mackey | mackey004--- | 1904 | 5/29-9/4 | Aberdeen Pippins | Southwest Washington League | , | |
| Robert Mackey | mackey001rob | 1904 | 4/28-5/3 | Fort Wayne Railroaders | Central League | , | |
| Robert Mackey | mackey001rob | 1904 | 5/7-7/8 | Marshalltown Grays | Iowa League | , | |
| Robert Mackey | mackey001rob | 1904 | 7/10-8/7 | Sioux City Soos | Western League | , | |
| Robert Mackey | mackey001rob | 1904 | 8/10-8/22 | Marshalltown Grays | Iowa League | , | |
| John Mackin | mackin000jac | 1904 | +8/16+ | Dollar Bay | Copper Country League | , | |
| Robert MacLatchie | mclatc001rob | 1904 | Hartford Senators | Connecticut State League | , | ||
| Robert MacLatchie | mclatc001rob | 1904 | +5/24+8/23+ | Pottstown | Pennsylvania League | , | |
| Art Madison | madiso002art | 1904 | 4/29-6/18 | Rochester Bronchos | Eastern League | , | |
| Art Madison | madiso002art | 1904 | Corning White Ponies | Southern Tier League | , | ||
| Bill Magee | magee-001wil | 1904 | 5/1-9/22 | Buffalo Bisons | Eastern League | , | |
| Sherry Magee | magee-001she | 1904 | Carlisle PA | Independent | , | ||
| Sherry Magee | magee-001she | 1904 | 6/29- | 95 g. | Philadelphia | National League | Philadelphia, PA |
| Harry Magers | magers000har | 1904 | preseason | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| Jake Magie | magie-001jac | 1904 | 5/6-9/14 | Syracuse Stars | New York State League | , | |
| George Magoon | magoon001geo | 1904 | 4/20-9/20 | Indianapolis Indians | American Association | , | |
| Mahaffey | 1904 | +6/17-6/29+ | Findlay OH | Independent | , | ||
| Mahaffey | 1904 | +7/23+ | Chic. Junction OH | Independent | , | ||
| Mahaffey | 1904 | +8/17-8/27+ | 6 g. | Canton OH | Independent | , | |
| Aaron Maher | maher-003mar | 1904 | +6/28-8/7+ | Missoula MT | Independent | , | |
| Tom Maher | maher-001tho | 1904 | 5/3-9/10 | Wilmington Peaches | Tri-State League | , | |
| Edward Mahley | 1904 | Coffeyville KS | Independent | , | |||
| William Mahling | mahlin001wil | 1904 | 5/14-9/28 | Newark Sailors | Eastern League | , | |
| Eugene Mahon | mahon-001eug | 1904 | 6 g. | Portland Browns | Pacific Coast League | , | |
| Eugene Mahon | mahon-001eug | 1904 | Seattle Siwashes | Pacific Coast League | , | ||
| Ed Mahoney | mahone001edw | 1904 | 5/6-9/5 | Fort Dodge Gypsum Eaters | Iowa League | , | |
| Willard Mains | mains-001wil | 1904 | 5/7-9/17 | Syracuse Stars | New York State League | , | |
| Edgar Maitland | maitla001edg | 1904 | 5/11-9/10 | Williamsport Millionaires | Tri-State League | , | |
| Major | major-004--- | 1904 | 9/5-9/9 | Des Moines Prohibitionists | Western League | , | |
| John Malarkey | malark001joh | 1904 | 4/20-9/16 | Columbus Senators | American Association | , | |
| Charlie Malay | malay-001cha | 1904 | 5/6-7/26 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Charlie Malay | malay-001cha | 1904 | 8/11-9/30 | Harrisburg Senators | Tri-State League | , | |
| Charlie Malay | malay-001cha | 1904 | Brooklyn-S-P | Independent | , | ||
| Mallory | 1904 | 6/9 | Binghamton Bingoes | New York State League | , | ||
| Malloy | 1904 | Cheraw SC | Independent | , | |||
| Maloney | 1904 | 107 g. | Fort Dodge Gypsum Eaters | Iowa League | , | ||
| Billy Maloney | malone003wil | 1904 | 4/20-9/20 | Minneapolis Millers | American Association | , | |
| Curley Maloney | malone005jam | 1904 | 4/27-7/30 | Corsicana Oil Citys | Texas League | , | |
| Curley Maloney | malone005jam | 1904 | 8/1-8/15 | Dallas Giants | Texas League | , | |
| John Maloney | malone002joh | 1904 | 4/29-5/4 | Colorado Springs Millionaires | Western League | , | |
| William Maloney | malone005wil | 1904 | +5/19-10/12 | Youngstown OH | Independent | , | |
| Nicholas Malvern | malver001nic | 1904 | 22 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| Mankie | mankie001--- | 1904 | 5/19- | 31 g. | Fargo | Northern League | , |
| Mankie | mankie001--- | 1904 | 7/5- | Bismarck ND | Independent | , | |
| Harry Manner | manner001har | 1904 | 4/21-9/25 | Montgomery Senators | Southern Association | , | |
| Tommy Manning | mannin001tho | 1904 | Norwich Reds | Connecticut State League | , | ||
| Manro | 1904 | Saugerties | Hudson River League | , | |||
| Lou Manske | manske001lou | 1904 | 5/15- | Green Bay WI | Independent | , | |
| Lou Manske | manske001lou | 1904 | 7/27-9/7 | Milwaukee Brewers | American Association | , | |
| Otto Manthey | manthe000ott | 1904 | 5/15-8/ | Green Bay WI | Independent | , | |
| Otto Manthey | manthe000ott | 1904 | 8/- | Iron Mt. MI | Independent | , | |
| Moxie Manuel | manuel001mar | 1904 | Vicksburg Hill Billies | Cotton States League | , | ||
| Art Marcan | marcan002art | 1904 | 145 g. | St. Paul Saints | American Association | , | |
| J. B. Marchant | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |||
| George Markley | markle001geo | 1904 | 5/1-6/14 | Corsicana Oil Citys | Texas League | , | |
| George Markley | markle001geo | 1904 | 75 g. | Houston Wanderers | South Texas League | , | |
| Billy Maroney | 1904 | Concord Marines | New England League | , | |||
| Billy Maroney | 1904 | Manchester | New England League | , | |||
| Billy Maroney | 1904 | Northampton MA | Independent | , | |||
| James Maroney | marone001--- | 1904 | 5/2 | Haverhill Hustlers | New England League | , | |
| Michael Marre | marre-001ang | 1904 | 28 ab | Baton Rouge Red Sticks | Cotton States League | , | |
| Michael Marre | marre-001ang | 1904 | Pine Bluff Lumbermen | Cotton States League | , | ||
| Michael Marre | marre-001ang | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | ||
| Marshall | marsha052--- | 1904 | 9/7-9/8 | Rochester Bronchos | Eastern League | , | |
| Archie Marshall | marsha001arc | 1904 | 5/6-8/29 | Troy Trojans | New York State League | , | |
| Archie Marshall | marsha001arc | 1904 | 8/31-9/18 | Utica Pent-Ups | New York State League | , | |
| Doc Marshall | marsha005wil | 1904 | 4/15- | 8 g. | Philadelphia | National League | Philadelphia, PA |
| Doc Marshall | marsha005wil | 1904 | 1 g. | New York | National League | New York, NY | |
| Doc Marshall | marsha005wil | 1904 | 13 g. | Boston | National League | Boston, MA | |
| Joe Marshall | marsha001jos | 1904 | 18 g. | Portland Browns | Pacific Coast League | , | |
| Joe Marshall | marsha001jos | 1904 | 83 g. | Boise Fruit Pickers | Pacific National League | , | |
| Martin | martin070--- | 1904 | 34 ab | Natchez Indians | Cotton States League | , | |
| Martin | martin069--- | 1904 | Chester | Pennsylvania League | , | ||
| Martin | martin120--- | 1904 | 4/30-5/14 | Manchester | New England League | , | |
| Martin | martin119--- | 1904 | 7/6 | New Bedford Whalers | New England League | , | |
| Clint Martin | martin002cli | 1904 | 5/19- | 51 g. | Grand Forks Forkers | Northern League | , |
| Clint Martin | martin002cli | 1904 | 13 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Dave Martin | martin001dav | 1904 | 5/19- | 35 g. | Crookston Crooks | Northern League | , |
| Dave Martin | martin001dav | 1904 | 8/17-9/17 | Toledo Mud Hens | American Association | , | |
| Frank Martin | martin001fra | 1904 | 5/19-6/6 | Duluth White Sox | Northern League | , | |
| Frank Martin | martin001fra | 1904 | 6/9-6/22 | Minneapolis Millers | American Association | , | |
| Frank Martin | martin001fra | 1904 | 6/26-8/5 | Indianapolis Indians | American Association | , | |
| Frank Martin | martin001fra | 1904 | 8/7-9/20 | St. Paul Saints | American Association | , | |
| Harry Martin | martin007har | 1904 | GraR-Giants | Independent | , | ||
| Harry Martin | martin007har | 1904 | 7/16-18,8/20 | Grand Rapids Orphans | Central League | , | |
| Joe Martin | martin006jos | 1904 | 4/20-9/20 | Columbus Senators | American Association | , | |
| Felix Martinke | martin003fel | 1904 | 16 g. | Spokane Indians | Pacific National League | , | |
| Miles Maryott | maryot001mil | 1904 | Univ. Virginia | College | , | ||
| Miles Maryott | maryot001mil | 1904 | 5/7-6/27+ | Keokuk Indians | Iowa League | , | |
| Miles Maryott | maryot001mil | 1904 | 6/30-7/5 | Sioux City Soos | Western League | , | |
| Miles Maryott | maryot001mil | 1904 | +7/19-9/5 | Keokuk Indians | Iowa League | , | |
| Miles Maryott | maryot001mil | 1904 | 9/17-9/19 | Sioux City Soos | Western League | , | |
| Masher | 1904 | 4/30 | Spokane Indians | Pacific National League | , | ||
| Cy? Mason | 1904 | 5/5-5/11 | Grand Rapids Orphans | Central League | , | ||
| Del Mason | mason-001ade | 1904 | 4/23- | 5 g. | Washington | American League | Washington, DC |
| Del Mason | mason-001ade | 1904 | Plattsburgh | Northern New York League | , | ||
| Del Mason | mason-001ade | 1904 | 5/30-9/28 | Baltimore Orioles | Eastern League | , | |
| Del Mason | mason-001ade | 1904 | Los Angeles Angels | Pacific Coast League | , | ||
| Harry Mason | mason-002har | 1904 | 5/6-9/17 | Troy Trojans | New York State League | , | |
| Nel Mason | mason-001nel | 1904 | no g. | Terre Haute Hottentots | Central League | , | |
| Bill Massey | massey001bil | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| Bill Massey | massey001bil | 1904 | 6/24-7/20 | Toronto Maple Leafs | Eastern League | , | |
| Bill Massey | massey001bil | 1904 | 8/5-9/20 | Kansas City Blues | American Association | , | |
| John Massing | massin001joh | 1904 | 433 ab | Natchez Indians | Cotton States League | , | |
| Thomas Masterson | master001tho | 1904 | 364 ab | Saugerties | Hudson River League | , | |
| Christy Mathewson | mathew001chr | 1904 | 48 g. | New York | National League | New York, NY | |
| Stanislaus Mathieu | mathie000sta | 1904 | 6/2 | Manchester | New England League | , | |
| Mathison | mathis004--- | 1904 | 5/10 | York Penn Parks | Tri-State League | , | |
| Jimmy Mathison | mathis002jam | 1904 | +8/3+ | 41 g. | Jacksonville Jays | South Atlantic League | , |
| Matson | matson003--- | 1904 | 8/28 | Olympia Senators | Southwest Washington League | , | |
| Al Mattern | matter001alo | 1904 | no g. | Rochester Bronchos | Eastern League | , | |
| Matthews | matthe023--- | 1904 | Macon Highlanders | South Atlantic League | , | ||
| Matthews | 1904 | +9/3-9/5 | Ot or Ke | Iowa League | , | ||
| Bert Matthews | 1904 | preseason | Rockford Red Sox | Illinois-Indiana-Iowa League | , | ||
| Harry Matthews | matthe001har | 1904 | 4/29-9/24 | Birmingham Barons | Southern Association | , | |
| Thomas Matthews | matthe001tho | 1904 | Decatur | Tennessee-Alabama League | , | ||
| Thomas Matthews | matthe001tho | 1904 | 5/16-6/10+ | Decatur | Tennessee-Alabama League | , | |
| William Matthews | matthe002wil | 1904 | 5/1-7/18+ | Harrisburg Senators | Tri-State League | , | |
| William Matthews | matthe002wil | 1904 | 9 g. | Buffalo Bisons | Eastern League | , | |
| Wilson Matthews | matthe004wil | 1904 | Galveston Sand Crabs | South Texas League | , | ||
| Wilson Matthews | matthe004wil | 1904 | 4/27-6/11 | Umpire | Texas League | , | |
| Wilson Matthews | matthe004wil | 1904 | 7/16- | Umpire | South Texas League | , | |
| Wilson Matthews | matthe004wil | 1904 | Umpire | Cotton States League | , | ||
| Mattie Mattison | 1904 | 51 g. | Coshocton OH | Independent | , | ||
| Al Mauch | mauch-001alb | 1904 | Little Rock Travelers | Southern Association | , | ||
| Al Mauch | mauch-001alb | 1904 | 5/17-9/30 | Lebanon | Tri-State League | , | |
| Patrick Mauch | mauch-001pat | 1904 | Pt. Washington | Independent | , | ||
| Harry Maupin | maupin001har | 1904 | 4/24-8/8 | St. Joseph Saints | Western League | , | |
| Harry Maupin | maupin001har | 1904 | 8/20-9/17 | Colorado Springs Millionaires | Western League | , | |
| Bert Maxwell | maxwel001jam | 1904 | Pine Bluff Lumbermen | Cotton States League | , | ||
| Bert Maxwell | maxwel001jam | 1904 | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | ||
| Elwood Maxwell | maxwel001c-- | 1904 | Savannah Pathfinders | South Atlantic League | , | ||
| Elwood Maxwell | maxwel001c-- | 1904 | Chester PA | Independent | , | ||
| Elwood Maxwell | maxwel001c-- | 1904 | 6/8 | Wilmington Peaches | Tri-State League | , | |
| F. Maxwell | 1904 | Norwich Reds | Connecticut State League | , | |||
| Mayfield | 1904 | 4/4+ | Dallas-Tailors | Amateur | , | ||
| Mayfield | 1904 | 7/21 | Paris Parasites/Ardmore Territorians | Texas League | , | ||
| Jesse Mays | mays--001pik | 1904 | Columbus KS | Independent | , | ||
| Jesse Mays | mays--001pik | 1904 | Weir City Browns | Independent | , | ||
| Dan McAleese | mcalee001dan | 1904 | +7/23+ | Kent OH | Independent | , | |
| Dan McAleese | mcalee001dan | 1904 | +9/12+ | 35 g. | Sharon PA | Independent | , |
| Jack McAleese | mcalee001joh | 1904 | 5/27-6/16 | Binghamton Bingoes | New York State League | , | |
| Jack McAleese | mcalee001joh | 1904 | 6/29-9/10 | Corning White Ponies | Southern Tier League | , | |
| McAllister | 1904 | 16 g. | Newark OH | Independent | , | ||
| Sport McAllister | mcalli001lew | 1904 | 4/30-9/28 | Buffalo Bisons | Eastern League | , | |
| Tom McAndrew | mcandr002tho | 1904 | 5/6-9/18 | Utica Pent-Ups | New York State League | , | |
| McAndrews | mcandr007--- | 1904 | 7/29-8/10 | Penn Yan Grape Pickers | Southern Tier League | , | |
| Mike McAndrews | mcandr001mic | 1904 | Holyoke Paperweights | Connecticut State League | , | ||
| Pat? McAndrews | 1904 | 6/1-6/2 | San Antonio Bronchos | South Texas League | , | ||
| Patrick McAndrews | mcandr001pat | 1904 | no g. | Vicksburg Hill Billies | Cotton States League | , | |
| Frank McArdell | mcarde001fra | 1904 | +7/12-8/17 | Knoxville | Tennessee-Alabama League | , | |
| Harry McArdle | mcardl001har | 1904 | 408 ab | Paterson Intruders | Hudson River League | , | |
| Gene McAuliffe | mcauli002eug | 1904 | 8/8-8/11 | New Bedford Whalers | New England League | , | |
| Gene McAuliffe | mcauli002eug | 1904 | 8/17 | Boston | National League | Boston, MA | |
| Sam McBirney | mcbirn000sam | 1904 | 5/13 | Sioux City Soos | Western League | , | |
| Sam McBirney | mcbirn000sam | 1904 | Stanton SC | Independent | , | ||
| McBride | mcbrid017--- | 1904 | 1 g. | Anniston | Tennessee-Alabama League | , | |
| George McBride | mcbrid001geo | 1904 | 4/24-9/25 | St. Joseph Saints | Western League | , | |
| Sammy McBurney | 1904 | Sioux City IA | Independent | , | |||
| Sammy McBurney | 1904 | Canton SD | Independent | , | |||
| McCabe | mccabe013--- | 1904 | Sacramento | California State League | , | ||
| Bill McCabe | mccabe005wil | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| Francis McCabe | mccabe002fra | 1904 | Dartmouth Col | College | , | ||
| William McCabe | mccabe008wil | 1904 | Lancaster PA | Independent | , | ||
| William McCabe | mccabe008wil | 1904 | 6/28-8/13 | Wilmington Peaches | Tri-State League | , | |
| Charles McCafferty | mccaff002cha | 1904 | Rock Island Islanders | Illinois-Indiana-Iowa League | , | ||
| Jerry McCall | mccall001jer | 1904 | Grand Rapids MI | Independent | , | ||
| Jack McCallister | mccall001jac | 1904 | 16 g. | Newark OH | Independent | , | |
| McCallum | mccall010--- | 1904 | 7/20-7/26 | Montreal Royals | Eastern League | , | |
| Charles McCann | 1904 | +6/19+ | Canton OH | Independent | , | ||
| Gene McCann | mccann001hen | 1904 | 4/29-7/4 | Jersey City Skeeters | Eastern League | , | |
| Gene McCann | mccann001hen | 1904 | 8/25-9/28 | Jersey City Skeeters | Eastern League | , | |
| Mike McCann | mccann001mic | 1904 | 4/23-9/24 | Little Rock Travelers | Southern Association | , | |
| William McCann | mccann000bil | 1904 | Paterson NJ | Independent | , | ||
| Daniel McCarter | mccart006dan | 1904 | U. South Dakota | College | , | ||
| Daniel McCarter | mccart006dan | 1904 | +6/20+ | Canton SD | Independent | , | |
| Daniel McCarter | mccart006dan | 1904 | U. South Dakota | College | , | ||
| McCarthy | mccart094--- | 1904 | St. Albans | Northern New York League | , | ||
| McCarthy | mccart094--- | 1904 | 8/31-9/1 | Elmira | Southern Tier League | , | |
| McCarthy | mccart081--- | 1904 | 7/16 | Lawrence Colts | New England League | , | |
| Arch McCarthy | mccart001arc | 1904 | 4/29-9/28 | Montreal Royals | Eastern League | , | |
| Arch McCarthy | mccart001arc | 1904 | no g. | Altoona Mountaineers | Tri-State League | , | |
| Dennis McCarthy | mccart001den | 1904 | 4/26-7/13 | Omaha Rangers | Western League | , | |
| Dennis McCarthy | mccart001den | 1904 | Topeka Saints | Missouri Valley League | , | ||
| J. L. McCarthy | mccart000jl- | 1904 | 6/28- | New Bedford Whalers | New England League | , | |
| J. L. McCarthy | mccart000jl- | 1904 | -8/24 | Concord Marines | New England League | , | |
| Jack McCarthy | mccart003joh | 1904 | California League | , | |||
| Jack McCarthy | mccart003joh | 1904 | 115 g. | Chicago | National League | Chicago, IL | |
| Jack McCarthy | mccart004jac | 1904 | 4/3- | Umpire | Pacific Coast League | , | |
| Jack McCarthy | mccart004jac | 1904 | 4/27-6/5 | Umpire | Pacific National League | , | |
| Jack McCarthy | mccart004jac | 1904 | Umpire | Western League | , | ||
| Jack McCarthy | mccart004jac | 1904 | +7/4-8/25+ | Umpire | Pacific Coast League | , | |
| Joe McCarthy | mccart004jos | 1904 | 5/18-6/5 | Dallas Giants | Texas League | , | |
| Joe McCarthy | mccart004jos | 1904 | 6/9-7/4 | Corsicana Oil Citys | Texas League | , | |
| Joe McCarthy | mccart004jos | 1904 | 52 g. | Columbia Skyscrapers | South Atlantic League | , | |
| Joe McCarthy | mccart004jos | 1904 | San Francisco | California State League | , | ||
| Joe McCarthy | mccart003jos | 1904 | 6/29-9/10 | Corning White Ponies | Southern Tier League | , | |
| Teddy McCarthy | 1904 | Niagara Univ. | College | , | |||
| Teddy McCarthy | 1904 | +6/17+ | Corning NY | Independent | , | ||
| Teddy McCarthy | 1904 | Kane | Interstate League | , | |||
| McCaughey | 1904 | +5/22+ | Kansas City Blues | American Association | , | ||
| Albert McCauley | mccaul007--- | 1904 | +6/27-8/18 | Decatur | Tennessee-Alabama League | , | |
| Pat McCauley | mccaul001pat | 1904 | 5/25-8/16 | Rochester Bronchos | Eastern League | , | |
| T. B. McCauley | mccaul007--- | 1904 | +6/27-8/18 | Decatur | Tennessee-Alabama League | , | |
| Billy McCausland | mccaus001wil | 1904 | 4/28-5/1 | Des Moines Prohibitionists | Western League | , | |
| Billy McCausland | mccaus001wil | 1904 | +7/15+ | Cripple Creek CO | Independent | , | |
| Bernard McCay | mccay-001ber | 1904 | 4/21-9/24 | Atlanta Crackers | Southern Association | , | |
| Harry McChesney | mcches001har | 1904 | 4/24-9/16 | Des Moines Prohibitionists | Western League | , | |
| Harry McChesney | mcches001har | 1904 | 9/17-10/9 | Chicago | National League | Chicago, IL | |
| James McClain | mcclai001jam | 1904 | 6/15-7/12 | Grand Rapids Orphans | Central League | , | |
| Jimmy McClaren | mcclar000jim | 1904 | +7/4+ | Pitt.-P.A.C. | Independent | , | |
| Walter McClelland | 1904 | Pawt.-St. Marys | Independent | , | |||
| Howard McClintock | mcclin001wil | 1904 | 5/12 | Houston Wanderers | South Texas League | , | |
| Charles McCloskey | mcclos002cha | 1904 | +9/5+ | Homestead PA | Independent | , | |
| John McCloskey | mcclos001joh | 1904 | 12 g. | Boise Fruit Pickers | Pacific National League | , | |
| Harry McCloud | mcclou002har | 1904 | 4/30-9/7 | Umpire | New England League | , | |
| William McCombs | mccomb001wil | 1904 | 5/11-9/12 | Wheeling Stogies | Central League | , | |
| McConnell | 1904 | 9/24 | Boise Fruit Pickers | Pacific National League | , | ||
| Amby McConnell | mcconn001amb | 1904 | 5/6-9/17 | Troy Trojans | New York State League | , | |
| George McConnell | mcconn001geo | 1904 | 4/30-9/12 | Wheeling Stogies | Central League | , | |
| Jack McConnell | mcconn002joh | 1904 | 4/24-9/25 | St. Joseph Saints | Western League | , | |
| John McConnell | mcconn001joh | 1904 | 23 g. | Sedalia Goldbugs | Missouri Valley League | , | |
| Lanty McConnell | mcconn002lan | 1904 | 23 g. | Sedalia Goldbugs | Missouri Valley League | , | |
| Thomas McConnell | mcconn001tho | 1904 | 5/16-6/1+ | Chattanooga | Tennessee-Alabama League | , | |
| Tom? McConnell | mcconn012--- | 1904 | 6/11-7/8 | Anniston | Tennessee-Alabama League | , | |
| John McCord | mccord001joh | 1904 | Greenville Cotton Pickers | Cotton States League | , | ||
| John McCord | mccord001joh | 1904 | Coshoocton OH | Independent | , | ||
| Mike McCormack | mccorm003mic | 1904 | Brooklyn | National League | Brooklyn, NY | ||
| McCormick | mccorm030--- | 1904 | 4/30 | Manchester | New England League | , | |
| McCormick | 1904 | Brookhaven | Delta League | , | |||
| McCormick | mccorm039--- | 1904 | 7/22- | Cloudersport PA | Independent | , | |
| McCormick | mccorm039--- | 1904 | 8/24-9/8 | Coudersport | Southern Tier League | , | |
| Barry McCormick | mccorm002wil | 1904 | - 8/30 | 113 g. | Washington | American League | Washington, DC |
| F. H. McCormick | 1904 | GrFa-Mavericks | Independent | , | |||
| Frank McCormick | mccorm002fra | 1904 | Coudersport | Southern Tier League | , | ||
| Harry McCormick | mccorm004har | 1904 | 4/14- | 55 g. | New York | National League | New York, NY |
| Harry McCormick | mccorm004har | 1904 | 66 g. | Pittsburgh | National League | Pittsburgh, PA | |
| Jim McCormick | mccorm002jim | 1904 | Ilion Typewriters | New York State League | , | ||
| Jim McCormick | mccorm002jim | 1904 | Kingston Colonials | Hudson River League | , | ||
| McCoy | mccoy-024--- | 1904 | 8/11-9/10 | Wilmington Peaches | Tri-State League | , | |
| John McCrane | mccran001joh | 1904 | Meriden Silverites | Connecticut State League | , | ||
| Judge McCredie | mccred001wal | 1904 | Portland Browns | Pacific Coast League | , | ||
| Tom McCreery | mccree001tho | 1904 | 4/20-9/20 | Indianapolis Indians | American Association | , | |
| McCue | mccue-007--- | 1904 | Lodi | California State League | , | ||
| McCue | mccue-002--- | 1904 | Sacramento | California State League | , | ||
| Charles McCullough | mccull001cha | 1904 | Bridgeport Orators | Connecticut State League | , | ||
| Hugh McCullum | mccull003hug | 1904 | 4/27-7/17 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Hugh McCullum | mccull003hug | 1904 | 7/18-8/4 | Corsicana Oil Citys | Texas League | , | |
| Merritt McCully | mccull000mer | 1904 | Olympia High Sch | High School | , | ||
| Hugh McCune | 1904 | Tren.-YMCA | Independent | , | |||
| Jack McCusker | 1904 | 7/24- | Camden NJ | Independent | , | ||
| Michael McDermott | mcderm003mic | 1904 | 4/30-5/16 | Umpire | New England League | , | |
| Tom McDermott | mcderm005tho | 1904 | 7/27 | Fall River Indians | New England League | , | |
| Will McDevitt | mcdevi001wil | 1904 | 114 g. | Houston Wanderers | South Texas League | , | |
| Eddie McDill | mcdill001edw | 1904 | +5/5+ | Sedalia Goldbugs | Missouri Valley League | , | |
| Eddie McDill | mcdill001edw | 1904 | 121 g. | Topeka Saints | Missouri Valley League | , | |
| McDonald | mcdona067--- | 1904 | 12 g. | Grand Rapids Orphans | Central League | , | |
| Charles McDonald | mcdona004cha | 1904 | 5/4 | Minneapolis Millers | American Association | , | |
| E. L. McDonald | mcdona000el- | 1904 | 5/26-6/4 | Roseburg Shamrocks | Oregon State League | , | |
| Edward McDonald | mcdona002edw | 1904 | Hudson River League | , | |||
| Edward McDonald | mcdona002edw | 1904 | 9/18 | Albany Senators | New York State League | , | |
| John McDonald | mcdona008joh | 1904 | 3 g. | Tacoma Tigers | Pacific Coast League | , | |
| Joseph McDonald | mcdona003jos | 1904 | 5/10-10/1 | Lebanon | Tri-State League | , | |
| Malcolm McDonald | mcdona002mal | 1904 | 8/21 | Newark Sailors | Eastern League | , | |
| Malcolm McDonald | mcdona002mal | 1904 | 9/11-9/12 | Newark Sailors | Eastern League | , | |
| McDonough | mcdono014--- | 1904 | +7/4+ | Butte-Reduction | Independent | , | |
| William McDonough | mcdono001wil | 1904 | 4/30-5/12 | Grand Rapids Orphans | Central League | , | |
| William McDonough | mcdono001wil | 1904 | 24 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Sandy McDougal | mcdoug002joh | 1904 | 5/9-7/10 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Sandy McDougal | mcdoug002joh | 1904 | 7/13-9/17 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Pryor McElveen | mcelve001pry | 1904 | 5/16-8/3 | Knoxville | Tennessee-Alabama League | , | |
| James McEvoy | mcevoy000jam | 1904 | +10/8+ | Rich.-Imperials | Independent | , | |
| John McEvoy | 1904 | +10/8+ | Rich.-Imperials | Independent | , | ||
| John McFall | 1904 | Charleston Col | College | , | |||
| John McFall | 1904 | Char.-YMCA | Independent | , | |||
| Dan McFarlan | mcfarl002dan | 1904 | 46 g. | Boise Fruit Pickers | Pacific National League | , | |
| Chappie McFarland | mcfarl002cha | 1904 | 32 g. | St. Louis | National League | St. Louis, MO | |
| Herm McFarland | mcfarl001her | 1904 | 4/29-9/28 | Baltimore Orioles | Eastern League | , | |
| Monte McFarland | mcfarl001mon | 1904 | 120 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| Roy McFarland | mcfarl001roy | 1904 | 5/21-7/4 | Eugene Blues | Oregon State League | , | |
| John McFarlin | mcfarl001j-- | 1904 | Jacksonv. State | College | , | ||
| John McFarlin | mcfarl001j-- | 1904 | +6/3-6/18+ | Anniston | Tennessee-Alabama League | , | |
| John McFarlin | mcfarl001j-- | 1904 | Decatur | Tennessee-Alabama League | , | ||
| John McFarlin | mcfarl001j-- | 1904 | +8/17 | Sheffield | Tennessee-Alabama League | , | |
| McFarren | 1904 | +5/30-7/14+ | Palouse WA | Independent | , | ||
| Charles McGau | 1904 | Dayton Veterans | Central League | , | |||
| Connie McGeehan | mcgeeh001cor | 1904 | 5/3-9/30 | Harrisburg Senators | Tri-State League | , | |
| Charles McGill | mcgill002cha | 1904 | 22+ g. | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| Willie McGill | mcgill005wil | 1904 | Norwich Reds | Connecticut State League | , | ||
| Barney McGilligan | 1904 | 10 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | ||
| Hugh McGilligan | mcgill001hug | 1904 | 5/6-5/11 | Binghamton Bingoes | New York State League | , | |
| Bill McGilvray | mcgilv001wil | 1904 | 4/24-9/25 | Denver Grizzlies | Western League | , | |
| Jim McGinley | mcginl001jam | 1904 | 5/2-9/17 | Haverhill Hustlers | New England League | , | |
| Jim McGinley | mcginl001jam | 1904 | 9/22- | 3 g. | St. Louis | National League | St. Louis, MO |
| Stoney McGlynn | mcglyn001uly | 1904 | 5/10-9/27 | York Penn Parks | Tri-State League | , | |
| McGonigle | 1904 | 8/26 | Lebanon | Tri-State League | , | ||
| Art McGovern | mcgove001art | 1904 | 4/30-8/23 | Lowell Tigers | New England League | , | |
| Jack McGrath | 1904 | +6/13+ | Umpire | South Atlantic League | , | ||
| McGraw | mcgraw011--- | 1904 | 5/10-5/11 | Fall River Indians | New England League | , | |
| Bernard McGraw | mcgraw009--- | 1904 | +7/14+ | St. Albans | Northern New York League | , | |
| John McGraw | mcgraw003joh | 1904 | New York | National League | New York, NY | ||
| Eugene McGreevy | mcgree001eug | 1904 | 18 g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| Ted McGrew | mcgrew001har | 1904 | 4/28-5/29 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Ted McGrew | mcgrew001har | 1904 | 5/30-7/30 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Ted McGrew | mcgrew001har | 1904 | 7/31-9/9 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Albert McGuire | mcguir001alb | 1904 | 106 g. | Boone Coal Miners | Iowa League | , | |
| Deacon McGuire | mcguir006jam | 1904 | New York | American League | New York, NY | ||
| Jim McGuire | mcguir001jam | 1904 | 6/24-9/18 | Utica Pent-Ups | New York State League | , | |
| William McGuire | mcguir002wil | 1904 | 5/7-9/5 | Boone Coal Miners | Iowa League | , | |
| Thomas McGuirk | mcguir004tho | 1904 | Umpire | Hudson River League | , | ||
| William McGuirk | mcguir006wil | 1904 | 6/16 | Nashua | New England League | , | |
| Bob McHale | mchale001bob | 1904 | 4/24-9/25 | Denver Grizzlies | Western League | , | |
| Jim McHale | mchale001jam | 1904 | 129 g. | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Eugene McHugh | 1904 | Muskegon Reds | Independent | , | |||
| Irish McIlveen | mcilve001hen | 1904 | 6/18-9/30 | Williamsport Millionaires | Tri-State League | , | |
| Hector McInnes | mcinni001joh | 1904 | 4/30-7/4 | Salem Raglands | Oregon State League | , | |
| Hector McInnes | mcinni001joh | 1904 | 8/7-9/4 | Centralia Midgets | Southwest Washington League | , | |
| W. McInnes | mcinne000w-- | 1904 | 8/28 | Centralia Midgets | Southwest Washington League | , | |
| Harry McIntire | mcinti001joh | 1904 | 4/23-9/24 | Memphis Egyptians | Southern Association | , | |
| McIntyre | 1904 | Umpire | Central League | , | |||
| Butch McIntyre | mcinty001cha | 1904 | 4/28-8/6 | Evansville River Rats | Central League | , | |
| Butch McIntyre | mcinty001cha | 1904 | 33 g. | Boise Fruit Pickers | Pacific National League | , | |
| Matty McIntyre | mcinty001mat | 1904 | 152 g. | Detroit | American League | Detroit, MI | |
| Edward McIvor | mcivor001edw | 1904 | 7/18-8/15 | Dallas Giants | Texas League | , | |
| McKay | mckay-019--- | 1904 | 8/22 | Rochester Bronchos | Eastern League | , | |
| McKay | 1904 | Yale University | College | , | |||
| Bernard McKay | mccay-001ber | 1904 | San Francisco | California State League | , | ||
| Bernard McKay | mccay-001ber | 1904 | Oakland Oaks | Pacific Coast League | , | ||
| Bernard McKay | mccay-001ber | 1904 | Atlanta Crackers | Southern Association | , | ||
| Daniel Mckay | mckay-001spa | 1904 | +4/2-5/11+ | Baylor Univ. | College | , | |
| Reeve McKay | mckay-001ree | 1904 | 4/20-9/19 | Milwaukee Brewers | American Association | , | |
| Ed McKean | mckean001edw | 1904 | Toronto Maple Leafs | Eastern League | , | ||
| Benny McKee | 1904 | 41 g. | Youngstown OH | Independent | , | ||
| Ed McKelvey | mckelv001f-- | 1904 | Enid Evangelists | Southwestern League | , | ||
| McKenna | 1904 | 4/30-5/12 | Grand Rapids Orphans | Central League | , | ||
| McKenna | 1904 | 44 g. | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | ||
| James McKenna | mckenn001jam | 1904 | 13 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| John McKenzie | mckenz001joh | 1904 | 5/7-6/14 | Marshalltown Grays | Iowa League | , | |
| Francis McKeon | mckeon001fra | 1904 | Independent | , | |||
| Ed McKernan | mckern001edw | 1904 | no g. | Little Rock Travelers | Southern Association | , | |
| Ed McKernan | mckern001edw | 1904 | 118 g. | Charleston Sea Gulls | South Atlantic League | , | |
| James McKevitt | mckevi001jam | 1904 | 38 g. | Boise Fruit Pickers | Pacific National League | , | |
| Thomas McKinley | mckinl001tho | 1904 | 7/18-9/11 | Dayton Veterans | Central League | , | |
| J. L. McKowan | 1904 | 5/3 | Wheeling Stogies | Central League | , | ||
| William McKune | mckune001wil | 1904 | +3/5+ | Santa Clara Col | College | , | |
| William McKune | mckune001wil | 1904 | San Francisco | California State League | , | ||
| William McKune | mckune001wil | 1904 | Oakland | California State League | , | ||
| William McKune | mckune001wil | 1904 | 5/14-6/26+ | Eugene Blues | Oregon State League | , | |
| William McKune | mckune001wil | 1904 | +7/23+ | Oakland Oaks | Pacific Coast League | , | |
| William McKune | mckune001wil | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| William McKune | mckune001wil | 1904 | Seattle Siwashes | Pacific Coast League | , | ||
| Ed McLane | mclane001edw | 1904 | Burlington | Northern New York League | , | ||
| Ed McLane | mclane001edw | 1904 | Plattsburgh | Northern New York League | , | ||
| McLaughlin | 1904 | 8/1- | 10 g. | Sharon PA | Independent | , | |
| Barney McLaughlin | mclaug003ber | 1904 | 4/30-9/17 | Lowell Tigers | New England League | , | |
| Edward McLaughlin | mclaug001edw | 1904 | 43 g. | Augusta Tourists | South Atlantic League | , | |
| George McLaughlin | mclaug003geo | 1904 | 226 g. | Tacoma Tigers | Pacific Coast League | , | |
| Thomas McLaughlin | mclaug001tho | 1904 | +6/8-6/24+ | Bessemer | Tennessee-Alabama League | , | |
| Warren McLaughlin | mclaug001war | 1904 | New London Whalers | Connecticut State League | , | ||
| Warren McLaughlin | mclaug001war | 1904 | Charleston Sea Gulls | South Atlantic League | , | ||
| Warren McLaughlin | mclaug001war | 1904 | Augusta Tourists | South Atlantic League | , | ||
| Ralph McLaurin | mclaur001ral | 1904 | +5/28+ | Jacksonville Jays | South Atlantic League | , | |
| Edward McLean | 1904 | Fordham College | College | , | |||
| Larry McLean | mclean001joh | 1904 | 27 g. | St. Louis | National League | St. Louis, MO | |
| Sam McLean | mclean001fra | 1904 | Norwich Reds | Connecticut State League | , | ||
| Thomas McLean | 1904 | Hudson Marines | Hudson River League | , | |||
| Harry McLear | mclear001har | 1904 | 116 g. | Pittsburg Coal Diggers | Missouri Valley League | , | |
| McLeavy | mcleav000--- | 1904 | Rich.-Brownies | , | |||
| McMahon | mcmaho019--- | 1904 | 7/1-7/15 | Hornellsville Maple Cities | Southern Tier League | , | |
| Morrison McMahon | mcmaho001m-- | 1904 | Haverhill Hustlers | New England League | , | ||
| William McMahon | mcmaho001wil | 1904 | 5/2- | Manchester | New England League | , | |
| William McMahon | mcmaho001wil | 1904 | 8/30 | Nashua | New England League | , | |
| John McMakin | mcmaki001joh | 1904 | 4/25-9/24 | Atlanta Crackers | Southern Association | , | |
| McManus | mcmanu013--- | 1904 | 8/23-8/25 | Rochester Bronchos | Eastern League | , | |
| McManus | mcmanu009--- | 1904 | Victoria BC | Independent | , | ||
| Frank McManus | mcmanu001fra | 1904 | 1 g. | Detroit | American League | Detroit, MI | |
| Frank McManus | mcmanu001fra | 1904 | 5/14-9/17 | Montreal Royals | Eastern League | , | |
| Frank McManus | mcmanu001fra | 1904 | - 10/8 | 4 g. | New York | American League | New York, NY |
| John McMillan | 1904 | Buffalo Bisons | Eastern League | , | |||
| John McMillan | mcmill001joh | 1904 | 5/16-6/28+ | Anniston | Tennessee-Alabama League | , | |
| Tommy McMillan | mcmill004tho | 1904 | 15 g. | Augusta Tourists | South Atlantic League | , | |
| Hugh McMurray | mcmurr002hug | 1904 | 4/27-6/25 | Fort Worth Panthers | Texas League | , | |
| Hugh McMurray | mcmurr002hug | 1904 | 64 g. | Beaumont Millionaires | South Texas League | , | |
| Bill McNamara | mcnama001wil | 1904 | 5/6-7/10 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Bill McNamara | mcnama001wil | 1904 | 7/12-9/17 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Bill McNamara | mcnama001wil | 1904 | 9/27-9/28 | Rochester Bronchos | Eastern League | , | |
| Thomas McNamara | 1904 | 4/26- | Umpire | South Atlantic League | , | ||
| Thomas McNamara | 1904 | Umpire | Tri-State League | , | |||
| Harry McNeal | mcneal001joh | 1904 | 5/10-7/9 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Harry McNeal | mcneal001joh | 1904 | 7/13-9/15 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Harry McNeal | mcneal001joh | 1904 | 9/22-9/28 | Baltimore Orioles | Eastern League | , | |
| Leon McNeal | mcneal001ski | 1904 | 5/8-5/22 | Aberdeen Pippins | Southwest Washington League | , | |
| Hugh McNeeley | mcneel001har | 1904 | 4/24-9/25 | Colorado Springs Millionaires | Western League | , | |
| McNeil | mcneil028--- | 1904 | 7/8-8/8 | Wellsville Oil Drillers | Southern Tier League | , | |
| Bernard McNeil | mcneil001ber | 1904 | 5/6-5/23 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Bernard McNeil | mcneil001ber | 1904 | 5/31-9/11 | Troy Trojans | New York State League | , | |
| James McNeil | mcneil004jam | 1904 | 6/16 | Altoona Mountaineers | Tri-State League | , | |
| Will McNeil | mcneil003wil | 1904 | +5/21-5/28+ | Crookston Crooks | Northern League | , | |
| Ed McNichol | mcnich001edw | 1904 | 7/9-10/3 | Boston | National League | Boston, MA | |
| Frank McNichols | mcnich001fra | 1904 | 4/22-9/20 | Minneapolis Millers | American Association | , | |
| Clyde McNutt | mcnutt001cly | 1904 | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | ||
| Frank McPartlin | mcpart002fra | 1904 | 4/28-8/18 | Little Rock Travelers | Southern Association | , | |
| John McPherson | mcpher002joh | 1904 | -7/10 | 15 g. | Philadelphia | National League | Philadelphia, PA |
| John McPherson | mcpher002joh | 1904 | 8/25-9/5 | Lebanon | Tri-State League | , | |
| James McQuaid | mcquai001jam | 1904 | Kingston Colonials | Hudson River League | , | ||
| Mart McQuaid | mcquai001mor | 1904 | Umpire | Illinois-Indiana-Iowa League | , | ||
| George McQuillan | mcquil002geo | 1904 | 18 g. | Paterson Intruders | Hudson River League | , | |
| McShane | mcshan001--- | 1904 | +8/10+ & earlier | Chattanooga | Tennessee-Alabama League | , | |
| Michael McShane | mcshan001mic | 1904 | 7 ab | Baton Rouge Red Sticks | Cotton States League | , | |
| Michael McShane | mcshan001mic | 1904 | 11 g. | Brookhaven | Delta League | , | |
| Dan McSorley | 1904 | Mt. Carmel | , | ||||
| James McSorley | mcsorl001jam | 1904 | 5/14-5/24 | Syracuse Stars | New York State League | , | |
| Daniel McSurdy | mcsurd001dan | 1904 | Carlisle | Pennsylvania League | , | ||
| Daniel McSurdy | mcsurd001dan | 1904 | Mount Carmel PA | Independent | , | ||
| John McWatters | 1904 | 4/30- | Umpire | Central League | , | ||
| Al Meader | meader001al- | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | ||
| Joseph Meagher | meaghe001jos | 1904 | Roch.-Navals | Rochester Indoor League | , | ||
| Al Meander | 1904 | 31 g. | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | ||
| Pat Meaney | meaney002pat | 1904 | 208 g. | San Francisco Seals | Pacific Coast League | , | |
| Mears | 1904 | 5/2-5/17 | Grand Rapids Orphans | Central League | , | ||
| F. Meckenson | 1904 | May | 5 g. | Burlington River Rats | Iowa League | , | |
| J. H. Meckenson | 1904 | 5/7-8/10+ | Burlington River Rats | Iowa League | , | ||
| Leonard Medlenka | 1904 | Hous.-Culmore | Independent | , | |||
| Harry Meek | meek--001her | 1904 | 124 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| Billy Mehl | mehl--001wil | 1904 | 5/22-5/30 | Fargo | Northern League | , | |
| Billy Mehl | mehl--001wil | 1904 | 6/27-7/31 | Boone Coal Miners | Iowa League | , | |
| Billy Mehl | mehl--001wil | 1904 | Bismarck SD | Independent | , | ||
| Omar Mehl | mehl--001oma | 1904 | Pittsburg Coal Diggers | Missouri Valley League | , | ||
| Kid Melcher | melche001--- | 1904 | New Hope PA | Independent | , | ||
| Henry Melchoir | melchi001hen | 1904 | 4/30-6/3 | Grand Rapids Orphans | Central League | , | |
| Henry Melchoir | melchi001hen | 1904 | 6/7-9/6 | Evansville River Rats | Central League | , | |
| Bill Mellor | mellor001wil | 1904 | 4/21-5/25 | Atlanta Crackers | Southern Association | , | |
| Meloy | meloy-000--- | 1904 | 8/11 | Wilmington Peaches | Tri-State League | , | |
| John Menefee | menefe001joh | 1904 | Johnstown Johnnies | Pennsylvania League | , | ||
| Tom Menefee | menefe001tho | 1904 | 5/5 | Boise Fruit Pickers | Pacific National League | , | |
| Samuel Meniece | meniec001sam | 1904 | Big Duluth | Independent | , | ||
| Samuel Meniece | meniec001sam | 1904 | 8/13 | Duluth White Sox | Northern League | , | |
| Samuel Meniece | meniec001sam | 1904 | -9/25 | Big Duluth | Independent | , | |
| Elmer Meredith | meredi001elm | 1904 | 4/20-5/18 | Milwaukee Brewers | American Association | , | |
| Elmer Meredith | meredi001elm | 1904 | 5/30- | 11 g. | Salt Lake City Elders | Pacific National League | , |
| Elmer Meredith | meredi001elm | 1904 | 12 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Elmer Meredith | meredi001elm | 1904 | Decatur Commodores | Illinois-Indiana-Iowa League | , | ||
| Arthur Merkle | merkle001art | 1904 | Boucher MT | Amateur | , | ||
| Ed Merrill | merril001--- | 1904 | Rockford Red Sox | Illinois-Indiana-Iowa League | , | ||
| Jack Merrill | 1904 | 8/12-9/1 | Evansville River Rats | Central League | , | ||
| Merritt | merrit001--- | 1904 | 50 g. | Jackson Senators | Delta League | , | |
| Bill Merritt | merrit001bil | 1904 | 6/17- | Manchester | New England League | , | |
| Bill Merritt | merrit001bil | 1904 | Nashua | New England League | , | ||
| Bill Merritt | merrit001bil | 1904 | -9/17 | Haverhill Hustlers | New England League | , | |
| George Merritt | merrit002geo | 1904 | 5/2-9/28 | Jersey City Skeeters | Eastern League | , | |
| Sidney Merryman | merrym001sid | 1904 | 5/2-5/16 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Sidney Merryman | merrym001sid | 1904 | 5/30-7/28 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Sidney Merryman | merrym001sid | 1904 | 7/31-9/9 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| John Mertens | merten002joh | 1904 | Northern League | , | |||
| Sam Mertes | mertes001sam | 1904 | 148 g. | New York | National League | New York, NY | |
| Leo Mesmer | mesmer001leo | 1904 | Umpire | Illinois-Indiana-Iowa League | , | ||
| Jack Messerly | messer001joh | 1904 | 4/24-9/25 | Sioux City Soos | Western League | , | |
| Tom Messitt | messit001tom | 1904 | 4/25-5/9 | Colorado Springs Millionaires | Western League | , | |
| Tom Messitt | messit001tom | 1904 | 8/27-9/24 | Colorado Springs Millionaires | Western League | , | |
| James Metcalf | metcal002jam | 1904 | 5/21-7/5 | Sioux City Soos | Western League | , | |
| James Metcalf | metcal002jam | 1904 | 7/12-9/5 | Marshalltown Grays | Iowa League | , | |
| James Metcalf | metcal002jam | 1904 | U. Minnesota MedCollege | , | |||
| Monte Method | method001bel | 1904 | 4/28-8/15 | Corsicana Oil Citys | Texas League | , | |
| Metz | 1904 | +5/7+ | Guthrie Blues | Southwestern League | , | ||
| Edward Metz | metz--000edd | 1904 | +5/1+ | Marshalltown IA | Independent | , | |
| Edward Metz | metz--000edd | 1904 | 5/24-9/3+ | Canton SD | Independent | , | |
| Benny Meyer | meyer-001ber | 1904 | +8/20-9/5 | Boone Coal Miners | Iowa League | , | |
| Meyers | 1904 | +7/11+ | Davenport River Rats | Illinois-Indiana-Iowa League | , | ||
| Arthur Meyers | meyers021--- | 1904 | 5/7-5/30+ | Waterloo Microbes | Iowa League | , | |
| George Meyers | meyers001geo | 1904 | 5/16-6/17+ | Huntsville | Tennessee-Alabama League | , | |
| Harry Meyers | meyers001har | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | ||
| Harry Meyers | meyers001har | 1904 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | ||
| O. S. Meyers | 1904 | 17 g. | Leavenworth Orioles | Missouri Valley League | , | ||
| O. S. Meyers | 1904 | Fort Scott Giants | Missouri Valley League | , | |||
| A. L. Middlebrook | middle001a-- | 1904 | 72 g. | Jacksonville Jays | South Atlantic League | , | |
| A. L. Middlebrook | middle001a-- | 1904 | Augusta Tourists | South Atlantic League | , | ||
| Charlie Middleton | middle002cha | 1904 | 5/6-9/5 | Fort Dodge Gypsum Eaters | Iowa League | , | |
| Miles | miles-007--- | 1904 | 5/13 | Camden | Tri-State League | , | |
| Miller | 1904 | +6/20-9/18 | Umpire | New York State League | , | ||
| Miller | 1904 | 86 g. | Newark OH | Independent | , | ||
| Miller | 1904 | 6 g. | Findlay OH | Independent | , | ||
| Miller | miller235--- | 1904 | 5/8-6/19 | Hoquiam Perfect Gentlemen | Southwest Washington League | , | |
| Miller | miller240--- | 1904 | 8/24-9/8 | Coudersport | Southern Tier League | , | |
| Miller | miller163--- | 1904 | 2 g. | Columbia | Tennessee-Alabama League | , | |
| Al Miller | miller005al- | 1904 | Memphis Egyptians | Southern Association | , | ||
| Charles Miller | miller032cha | 1904 | 5/2-8/5 | Evansville River Rats | Central League | , | |
| Chris Miller | miller002chr | 1904 | 120 g. | Columbia Skyscrapers | South Atlantic League | , | |
| Chris Miller | miller002chr | 1904 | Augusta Tourists | South Atlantic League | , | ||
| Chris Miller | miller002chr | 1904 | Savannah Pathfinders | South Atlantic League | , | ||
| Doc Miller | miller004roy | 1904 | Northern League | , | |||
| Doc Miller | miller004roy | 1904 | 8/4-8/7 | Denver Grizzlies | Western League | , | |
| Dusty Miller | miller004cha | 1904 | 4/23-9/22 | Memphis Egyptians | Southern Association | , | |
| Dusty Miller | miller001dak | 1904 | 4/24-7/27 | Omaha Rangers | Western League | , | |
| Dusty Miller | miller001dak | 1904 | 7/29-9/24 | Des Moines Prohibitionists | Western League | , | |
| Eric Miller | miller021--- | 1904 | 6/23 | Huntsville | Tennessee-Alabama League | , | |
| George Miller | miller005geo | 1904 | 5/21-5/24 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| George Miller | miller001geo | 1904 | 5/3-8/24 | Wheeling Stogies | Central League | , | |
| Harry Miller | miller013har | 1904 | preseason | Keokuk Indians | Iowa League | , | |
| Jack Miller | miller011jac | 1904 | 4/29-5/21 | Roseburg Shamrocks | Oregon State League | , | |
| Jack Miller | miller011jac | 1904 | Medford | Rogue River Valley | , | ||
| Jim Miller | miller016jam | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| Joseph Miller | miller008jos | 1904 | 26 g. | Crookston Crooks | Northern League | , | |
| Kohly Miller | miller001koh | 1904 | no g. | Colorado Springs Millionaires | Western League | , | |
| Kohly Miller | miller001koh | 1904 | 79 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Pete Miller | miller001pet | 1904 | 5/9 | Camden | Tri-State League | , | |
| Pete Miller | miller001pet | 1904 | 8/24- | Camden NJ | Independent | , | |
| Ray Miller | 1904 | +8/17-8/25+ | Waterloo Microbes | Iowa League | , | ||
| Roscoe Miller | miller001ros | 1904 | 19 g. | Pittsburgh | National League | Pittsburgh, PA | |
| Samuel Miller | miller001sam | 1904 | 26 g. | Springfield Ponies | Connecticut State League | , | |
| Walter Miller | miller005wal | 1904 | 5/7-9/6 | Grand Rapids Orphans | Central League | , | |
| William Miller | miller005w-- | 1904 | +6/24-6/30 | Enid Evangelists | Southwestern League | , | |
| William Miller | miller005w-- | 1904 | 7/1-8/4 | Dallas Giants | Texas League | , | |
| William Miller | miller005w-- | 1904 | 8/5-8/15 | Corsicana Oil Citys | Texas League | , | |
| William Miller | miller003wil | 1904 | +7/3+ | Zanesville OH | Independent | , | |
| Pat Millerick | miller002pat | 1904 | 4/21-9/24 | Birmingham Barons | Southern Association | , | |
| Billy Milligan | millig002wil | 1904 | - 5/15 | 5 g. | New York | National League | New York, NY |
| Billy Milligan | millig002wil | 1904 | 6/11-9/28 | Providence Grays | Eastern League | , | |
| Millington | millin003--- | 1904 | 4/29-4/30 | Roseburg Shamrocks | Oregon State League | , | |
| Mills | 1904 | 13 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , | ||
| Willie Mills | mills-004wil | 1904 | 4/29-7/21 | Toronto Maple Leafs | Eastern League | , | |
| Willie Mills | mills-004wil | 1904 | 7/27-8/30 | Rochester Bronchos | Eastern League | , | |
| Willie Mills | mills-004wil | 1904 | 9/4-9/23 | Baltimore Orioles | Eastern League | , | |
| Arthur Millsap | millsa001art | 1904 | 123 g. | Iola Gasbags | Missouri Valley League | , | |
| Milton | 1904 | Fargo | Northern League | , | |||
| Larry Milton | milton001sam | 1904 | 32 g. | Iola Gasbags | Missouri Valley League | , | |
| Cotton Minahan | minaha001edm | 1904 | Manhattan Col. | College | , | ||
| Cotton Minahan | minaha001edm | 1904 | 4/21-7/26 | Birmingham Barons | Southern Association | , | |
| Cotton Minahan | minaha001edm | 1904 | +8/24+ | Rutland | Northern New York League | , | |
| Paul Minish | minish001pau | 1904 | 5/16-8/20 | Huntsville | Tennessee-Alabama League | , | |
| Paul Minish | minish001pau | 1904 | Aurora IN | Independent | , | ||
| John Minnehan | minneh001joh | 1904 | 28 ab | Natchez Indians | Cotton States League | , | |
| Charles Minor | minor-002c-- | 1904 | 4/28-8/23 | Evansville River Rats | Central League | , | |
| Jack Miran | miran-001joh | 1904 | 5/6-5/31 | Utica Pent-Ups | New York State League | , | |
| Jack Miran | miran-001joh | 1904 | 6/2 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Jack Miran | miran-001joh | 1904 | 6/5-9/15 | Utica Pent-Ups | New York State League | , | |
| Mitchell | mitche016--- | 1904 | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | ||
| Mitchell | mitche016--- | 1904 | +7/16-8/31+ | Oskaloosa Quakers | Iowa League | , | |
| Mitchell | mitche008--- | 1904 | Sheffield | Tennessee-Alabama League | , | ||
| Felton Mitchell | mitche001fel | 1904 | 105 g. | Charleston Sea Gulls | South Atlantic League | , | |
| Fred Mitchell | mitche005fre | 1904 | 25 g. | Philadelphia | National League | Philadelphia, PA | |
| Fred Mitchell | mitche005fre | 1904 | 8 g. | Brooklyn | National League | Brooklyn, NY | |
| Jonas Mitchell | mitche034--- | 1904 | 7/1-7/17 | Dayton Veterans | Central League | , | |
| Jonas Mitchell | mitche034--- | 1904 | 7/22-7/23 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Mike Mitchell | mitche002mic | 1904 | 4/29-5/25 | Newark Sailors | Eastern League | , | |
| Mike Mitchell | mitche002mic | 1904 | 5/28 | Rochester Bronchos | Eastern League | , | |
| Mike Mitchell | mitche002mic | 1904 | 6/2-9/18 | Syracuse Stars | New York State League | , | |
| Homer Mock | mock--001hom | 1904 | 5/6-9/17 | Albany Senators | New York State League | , | |
| Frank Moffett | moffet001fra | 1904 | +5/30-8/3 | Knoxville | Tennessee-Alabama League | , | |
| Frank Moffett | moffet001fra | 1904 | Brevard | Carolina Interstate League | , | ||
| Lynn Moffett | 1904 | E. Liberty Acad | Academy | , | |||
| Elmer Moffitt | moffit001elm | 1904 | 4/28-9/1 | South Bend Greens | Central League | , | |
| Kid Mohler | mohler001kid | 1904 | Seattle Siwashes | Pacific Coast League | , | ||
| Mohr | 1904 | +7/13+ | Lisbon ND | Independent | , | ||
| Mohr | mohr--001man | 1904 | 11 g. | Fargo | Northern League | , | |
| Carlton Molesworth | molesw001car | 1904 | 4/21-9/21 | Montgomery Senators | Southern Association | , | |
| Monroe | 1904 | 8/31 | Houston Wanderers | South Texas League | , | ||
| Roy Monroe | monroe002r-- | 1904 | +9/27+ | Guthrie Blues | Southwestern League | , | |
| Milton Montgomery | montgo001mil | 1904 | Evansville River Rats | Central League | , | ||
| Roy Montgomery | montgo001roy | 1904 | 4/20-6/15 | Kansas City Blues | American Association | , | |
| Roy Montgomery | montgo001roy | 1904 | 6/24-8/7 | Indianapolis Indians | American Association | , | |
| Roy Montgomery | montgo001roy | 1904 | 8/11-9/19 | Louisville Colonels | American Association | , | |
| Harry Moody | moody-001har | 1904 | preseason | Des Moines Prohibitionists | Western League | , | |
| Harry Moody | moody-001har | 1904 | +5/10+ | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| Harry Moody | moody-001har | 1904 | +7/8-8/23+ | Oskaloosa Quakers | Iowa League | , | |
| Moore | moore-061--- | 1904 | +6/10-6/27+ | Burlington River Rats | Iowa League | , | |
| Moore | 1904 | +5/27+ | Urbana OH | Independent | , | ||
| Moore | 1904 | 11 g. | Coshocton OH | Independent | , | ||
| Carl Moore | moore-007car | 1904 | Rock Island Islanders | Illinois-Indiana-Iowa League | , | ||
| Earl Moore | moore-001ear | 1904 | 26 g. | Cleveland | American League | Cleveland, OH | |
| Edward Moore | moore-001edw | 1904 | Oakland | California State League | , | ||
| Frederick Moore | moore-001fre | 1904 | 312 ab | Monroe Hill Citys | Cotton States League | , | |
| Jesse Moore | moore-001jes | 1904 | 29 g. | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |
| John Moore | moore-009joh | 1904 | 23 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| John Moore | 1904 | Belleville OH | Independent | , | |||
| John Moore | 1904 | 9/4-9/12 | Newark OH | Independent | , | ||
| Paul Moore | moore-001pau | 1904 | 29 g. | Cedar Rapids Rabbits | Illinois-Indiana-Iowa League | , | |
| Paul Moore | moore-001pau | 1904 | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | ||
| Shef Moore | moore-001s-- | 1904 | 7/1-9/7 | Addison White Sox | Southern Tier League | , | |
| Wade Moore | moore-001wad | 1904 | 114 g. | San Antonio Bronchos | South Texas League | , | |
| Wade Moore | moore-001wad | 1904 | Beaumont Millionaires | South Texas League | , | ||
| Wade Moore | moore-001wad | 1904 | Houston Wanderers | South Texas League | , | ||
| James Moorhead | moorhe001jam | 1904 | 4/30-9/19 | Fall River Indians | New England League | , | |
| Charles Morales | morale001cha | 1904 | 6/14-7/22 | San Antonio Bronchos | South Texas League | , | |
| Augie Moran | moran-002aug | 1904 | MLB Umpire | National League | , | ||
| Charles Moran | moran-003cha | 1904 | 62 g. | Washington | American League | Washington, DC | |
| Charles Moran | moran-003cha | 1904 | 82 g. | St. Louis | American League | St. Louis, MO | |
| Charlie Moran | moran-002cha | 1904 | 4/27-8/14 | Dallas Giants | Texas League | , | |
| Herbie Moran | moran-002joh | 1904 | Peddie Institute | Academy | , | ||
| Herbie Moran | moran-002joh | 1904 | 5/28- | Cloudersport PA | Independent | , | |
| Herbie Moran | moran-002joh | 1904 | 8/24-9/8 | Coudersport | Southern Tier League | , | |
| Pat Moran | moran-002pat | 1904 | Boston | National League | Boston, MA | ||
| Patrick Moran | moran-001pat | 1904 | 253ab | Poughkeepsie Colts | Hudson River League | , | |
| More | more--001--- | 1904 | Oakland | California State League | , | ||
| Lew Moren | moren-001lew | 1904 | 1 g. | Pittsburgh | National League | Pittsburgh, PA | |
| Lew Moren | moren-001lew | 1904 | 5/17 | Baltimore Orioles | Eastern League | , | |
| Lew Moren | moren-001lew | 1904 | no g. | Brooklyn | National League | Brooklyn, NY | |
| Morgan | morgan058--- | 1904 | +8/2+ | Massillon OH | Independent | , | |
| Amos Morgan | morgan001amo | 1904 | 49 g. | Iola Gasbags | Missouri Valley League | , | |
| Cy Morgan | morgan003har | 1904 | 6/12-9/18 | Minneapolis Millers | American Association | , | |
| Cy Morgan | morgan003har | 1904 | 8 g. | St. Louis | American League | St. Louis, MO | |
| Louis Morgan | morgan001lou | 1904 | 21+ g. | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |
| Louis Morgan | morgan001lou | 1904 | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | ||
| Red Morgan | morgan003jam | 1904 | Georgetown Univ | College | , | ||
| Moriarty | 1904 | 7/27-7/31 | Little Rock Travelers | Southern Association | , | ||
| Bill Moriarty | moriar002wil | 1904 | Fargo | Northern League | , | ||
| Ed Moriarty | moriar001edw | 1904 | 5/1-5/23 | Newark Sailors | Eastern League | , | |
| Ed Moriarty | moriar001edw | 1904 | 9/5-9/28 | Newark Sailors | Eastern League | , | |
| George Moriarty | moriar003geo | 1904 | 4 g. | Chicago | National League | Chicago, IL | |
| George Moriarty | moriar003geo | 1904 | 7/7-9/19 | Toledo Mud Hens | American Association | , | |
| Morris | morris045--- | 1904 | 21+ g. | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |
| Ed Morris | morris001ed- | 1904 | Superior Longshoremen | Northern League | , | ||
| Samuel Morris | morris001ed- | 1904 | 30 g. | Joplin Miners | Missouri Valley League | , | |
| Walter Morris | morris010joh | 1904 | 4/30-9/2 | Beaumont Millionaires | South Texas League | , | |
| Bill Morrison | morris008wil | 1904 | 4/26-9/25 | Des Moines Prohibitionists | Western League | , | |
| Bill Morrison | morris008wil | 1904 | Oakland | California State League | , | ||
| John Morrison | morris014joh | 1904 | Hartford Senators | Connecticut State League | , | ||
| John Morrison | morris014joh | 1904 | Holyoke Paperweights | Connecticut State League | , | ||
| John Morrison | morris014joh | 1904 | 6/28- | Manchester | New England League | , | |
| John Morrison | morris014joh | 1904 | -7/22 | Lawrence Colts | New England League | , | |
| John Morrison | morris015joh | 1904 | +5/19-9/5 | Dollar Bay | Copper Country League | , | |
| Frank Morrissey | morris003mic | 1904 | 4/30-9/17 | Manchester | New England League | , | |
| Jack Morrissey | morris016joh | 1904 | 5/14-9/12 | Grand Rapids Orphans | Central League | , | |
| William Morrow | morrow002wil | 1904 | 4/29-7/4 | Roseburg Shamrocks | Oregon State League | , | |
| Morse | morse-012--- | 1904 | 6/17 | Rochester Bronchos | Eastern League | , | |
| Charles Morse | morse-001cha | 1904 | 5/6-9/10 | Ilion Typewriters | New York State League | , | |
| Frank Morse | morse-001fra | 1904 | 4/21-9/24 | Atlanta Crackers | Southern Association | , | |
| Pete Morton | morton001pet | 1904 | 5/21-8/7 | Grand Forks Forkers | Northern League | , | |
| Pete Morton | morton001pet | 1904 | 8/21-9/11 | Toledo Mud Hens | American Association | , | |
| Pete Morton | morton001pet | 1904 | Joplin Miners | Missouri Valley League | , | ||
| Moser/Mosier | 1904 | 5/22-5/25 | Spokane Indians | Pacific National League | , | ||
| Doc Moskiman | moskim001wil | 1904 | Oakland Oaks | Pacific Coast League | , | ||
| Charles Moss | moss--003cha | 1904 | 5/11-9/10 | Williamsport Millionaires | Tri-State League | , | |
| Charles Moss | moss--006cha | 1904 | 18 g. | Brookhaven | Delta League | , | |
| Anson Mott | mott--002ans | 1904 | +5/14-6/30 | Enid Evangelists | Southwestern League | , | |
| Anson Mott | mott--002ans | 1904 | 7/1-7/31 | Dallas Giants | Texas League | , | |
| Anson Mott | mott--002ans | 1904 | 8/1-8/15 | Corsicana Oil Citys | Texas League | , | |
| Ed. Mott | mott--002ans | 1904 | +5/14+ | Enid Evangelists | Southwestern League | , | |
| Banks Moulder | moulde001ban | 1904 | Ardmore IT | Independent | , | ||
| Banks Moulder | moulde001ban | 1904 | 8/8-8/15 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Mike Mowrey | mowrey001har | 1904 | 5/4-5/16 | Chester PA | Independent | , | |
| Mike Mowrey | mowrey001har | 1904 | 6/7-9/30 | Williamsport Millionaires | Tri-State League | , | |
| Mike Mowrey | mowrey001har | 1904 | +7/7+ | Savannah Pathfinders | South Atlantic League | , | |
| Mueller | 1904 | 8 g. | Sharon PA | Independent | , | ||
| Mueller | 1904 | +8/27-8/29+ | Waterloo Microbes | Iowa League | , | ||
| Walter Mueller | muelle002wal | 1904 | 4/20-5/18 | Milwaukee Brewers | American Association | , | |
| Walter Mueller | muelle002wal | 1904 | g. ? | Calumet Aristocrats | Copper Country League | , | |
| Walter Mueller | muelle002wal | 1904 | 7/15-9/23 | Jersey City Skeeters | Eastern League | , | |
| Edward Mulcahy | mulcah001edw | 1904 | +6/6+ | 16 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , |
| Edward Mulcahy | mulcah001edw | 1904 | +6/21-6/26+ | Waterloo Microbes | Iowa League | , | |
| Tom Mulcare | 1904 | 6/19 | Paris Parasites/Ardmore Territorians | Texas League | , | ||
| Cy Mulkey | mulkey001cyr | 1904 | 4/29-7/11 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Cy Mulkey | mulkey001cyr | 1904 | Umpire | Texas League | , | ||
| Cy Mulkey | mulkey001cyr | 1904 | 23 g. | Beaumont Millionaires | South Texas League | , | |
| Frank Mullane | mullan001fra | 1904 | Grand Forks Forkers | Northern League | , | ||
| Tony Mullane | mullan001ton | 1904 | 4/21-9/25 | Umpire | Southern Association | , | |
| Dominic Mullaney | mullan002dom | 1904 | 4/21-4/30 | Birmingham Barons | Southern Association | , | |
| Dominic Mullaney | mullan002dom | 1904 | 105 g. | Savannah Pathfinders | South Atlantic League | , | |
| Dominic Mullaney | mullan002dom | 1904 | 9/14-9/25 | Montgomery Senators | Southern Association | , | |
| Ed Mullaney | mullan001edw | 1904 | 4/30-9/19 | New Bedford Whalers | New England League | , | |
| Jim Mullen | mullin001jam | 1904 | 6/1- | 22 g. | Philadelphia | American League | Philadelphia, PA |
| Jim Mullen | mullin001jam | 1904 | 27 g. | Washington | American League | Washington, DC | |
| Jim Mullen | mullin001jam | 1904 | 19 g. | Philadelphia | American League | Philadelphia, PA | |
| Otho Mullen | mullen010--- | 1904 | 5/11- | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |
| Otho Mullen | mullen010--- | 1904 | 48 ab | Greenville Cotton Pickers | Cotton States League | , | |
| Otho? Mullen | mullen010--- | 1904 | 18 g. | Canton | Delta League | , | |
| Patrick Mullen | 1904 | no g. | Terre Haute Hottentots | Central League | , | ||
| Max Muller | muller002max | 1904 | 127 g. | Salt Lake City Elders | Pacific National League | , | |
| Max Muller | muller002max | 1904 | San Francisco | California State League | , | ||
| Arthur Mullin | mullin001art | 1904 | Fort Wayne Railroaders | Central League | , | ||
| Frank Mullin | 1904 | Toledo area | Independent | , | |||
| John Mullin | mullin001joh | 1904 | 5/9-9/30 | Williamsport Millionaires | Tri-State League | , | |
| George Munch | munch-000geo | 1904 | 4/21-5/30 | Minneapolis Millers | American Association | , | |
| Mundhenk | mundhe001t-- | 1904 | 8/1 | Dayton Veterans | Central League | , | |
| Red Munson | munson001cla | 1904 | preseason | St. Louis | National League | St. Louis, MO | |
| Red Munson | munson001cla | 1904 | 9/1-10/10 | Akron OH | Independent | , | |
| Red Murch | murch-001rob | 1904 | 79 g. | Yazoo City Zoos | Delta League | , | |
| Simmy Murch | murch-001sim | 1904 | 4/30-9/5 | Lawrence Colts | New England League | , | |
| Simmy Murch | murch-001sim | 1904 | 9/20- | 13 g. | St. Louis | National League | St. Louis, MO |
| Wilbur Murdoch | murdoc001wil | 1904 | Portland Browns | Pacific Coast League | , | ||
| Wilbur Murdoch | murdoc001wil | 1904 | 129 g. | Spokane Indians | Pacific National League | , | |
| Tim Murnane | murnan001tim | 1904 | President | New England League | , | ||
| Murphy | 1904 | Fitchburg MA | Independent | , | |||
| Connie Murphy | murphy002con | 1904 | 5/6-9/5 | Haverhill Hustlers | New England League | , | |
| Connie Murphy | murphy002con | 1904 | 9/10-10/1 | Harrisburg Senators | Tri-State League | , | |
| Danny Murphy | murphy006dan | 1904 | Philadelphia | American League | Philadelphia, PA | ||
| Dave Murphy | murphy001dav | 1904 | 4/30-9/19 | New Bedford Whalers | New England League | , | |
| Ed Murphy | murphy005edw | 1904 | 5/2-5/30 | Kansas City Blues | American Association | , | |
| Frank Murphy | murphy004fra | 1904 | Norwich Reds | Connecticut State League | , | ||
| Frank Murphy | murphy004fra | 1904 | -9/30 | Harrisburg Senators | Tri-State League | , | |
| Frank Murphy | murphy002fra | 1904 | 4/30-5/30 | Fall River Indians | New England League | , | |
| Henry Murphy | murphy006hen | 1904 | 8/13-9/12 | Providence Grays | Eastern League | , | |
| Howard Murphy | murphy001how | 1904 | 455 ab | Pine Bluff Lumbermen | Cotton States League | , | |
| John Murphy | murphy015joh | 1904 | 4/30- | Haverhill Hustlers | New England League | , | |
| John Murphy | murphy015joh | 1904 | -9/17 | Lawrence Colts | New England League | , | |
| John Murphy | murphy004joh | 1904 | 5/7-9/5 | Keokuk Indians | Iowa League | , | |
| John Murphy | murphy036--- | 1904 | Bismarck ND | Independent | , | ||
| Thomas Murphy | murphy001tho | 1904 | 4/30-8/29 | Haverhill Hustlers | New England League | , | |
| Murray | murray058--- | 1904 | 9/21 | Rochester Bronchos | Eastern League | , | |
| Alexander Murray | murray001ale | 1904 | Lancaster OH | Independent | , | ||
| Billy Murray | murray007wil | 1904 | 9/4 | Jersey City Skeeters | Eastern League | , | |
| Ernest Murray | murray001ern | 1904 | 35 g. | Charleston Sea Gulls | South Atlantic League | , | |
| James Murray | murray007jam | 1904 | 440 ab | Paterson Intruders | Hudson River League | , | |
| Jim Murray | murray008jam | 1904 | 4/29-9/28 | Toronto Maple Leafs | Eastern League | , | |
| John Murray | murray012joh | 1904 | 7/2-7/29+ | Penn Yan Grape Pickers | Southern Tier League | , | |
| John Murray | murray012joh | 1904 | 8/12-9/6 | Corning White Ponies | Southern Tier League | , | |
| John Murray | murray002j-- | 1904 | 124 g. | Pittsburg Coal Diggers | Missouri Valley League | , | |
| Red Murray | murray002joh | 1904 | 7/24-8/19 | Wellsville Oil Drillers | Southern Tier League | , | |
| Red Murray | murray002joh | 1904 | 8/23-9/2 | Addison White Sox | Southern Tier League | , | |
| Musante | 1904 | 8/6-8/13 | Utica Pent-Ups | New York State League | , | ||
| William Mutter | mutter001wil | 1904 | +5/29-6/26+ | Calumet Aristocrats | Copper Country League | , | |
| John Myatt | myatt-002joh | 1904 | Baton Rouge Red Sticks | Cotton States League | , | ||
| John Myatt | myatt-002joh | 1904 | 5/13- | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |
| John Myatt | myatt-002joh | 1904 | +7/1-7/23+ | Sheffield | Tennessee-Alabama League | , | |
| Bade Myers | myers-002wil | 1904 | 4/28-9/11 | Fort Wayne Railroaders | Central League | , | |
| James Myers | myers-003j-- | 1904 | +5/10-5/23+ | Waterloo Microbes | Iowa League | , | |
| John Myers | meyers004joh | 1904 | 4/28-5/27 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| John Myers | meyers004joh | 1904 | 5/30-7/29 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| John Myers | meyers004joh | 1904 | 8/3-9/9 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Joseph Myers | myers-002jos | 1904 | 6/8-9/27 | Lebanon | Tri-State League | , | |
| William Myers | myers-009wil | 1904 | GrFa-Mavericks | Independent | , | ||
| Tommy Mylett | mylett002tho | 1904 | 5/12- | 7 g. | Sharon PA | Independent | , |
| Tommy Mylett | mylett002tho | 1904 | 7/4-9/18 | Syracuse Stars | New York State League | , | |
| Tommy Mylett | mylett002tho | 1904 | +10/16 | Clev.-Baehrs | Independent | , | |
| Phil Nadeau | nadeau001phi | 1904 | 203 g. | Portland Browns | Pacific Coast League | , | |
| A. C. Nadler | nadler000ac- | 1904 | 4/29-7/4 | Roseburg Shamrocks | Oregon State League | , | |
| Nagle | 1904 | 25 g. | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | ||
| Nagle | 1904 | 83 g. | Niles OH | Independent | , | ||
| Andrew Nagle | nagle-001and | 1904 | +7/3+ | Niles OH | Independent | , | |
| Andrew Nagle | nagle-001and | 1904 | Hartford Senators | Connecticut State League | , | ||
| Andrew Nagle | nagle-001and | 1904 | 83 g. | Niles OH | Independent | , | |
| Judge Nagle | nagle-002wal | 1904 | San Francisco | California State League | , | ||
| Paul Nagle | nagle-001lef | 1904 | 5/19- | 54 g. | Grand Forks Forkers | Northern League | , |
| Paul Nagle | nagle-001lef | 1904 | +8/20-9/5 | Waterloo Microbes | Iowa League | , | |
| Richard Nallin | nallin001ric | 1904 | +5/16-7/18+ | Harrisburg Senators | Tri-State League | , | |
| William Nance | nance-001wil | 1904 | 4/20-9/20 | Kansas City Blues | American Association | , | |
| John Nash | nash--001joh | 1904 | +7/15+ | Cripple Creek CO | Independent | , | |
| John Nash | nash--001joh | 1904 | 7/19-9/22 | Colorado Springs Millionaires | Western League | , | |
| Billy Nattress | nattre001wil | 1904 | 4/30-9/28 | Buffalo Bisons | Eastern League | , | |
| Nausser | nausse000--- | 1904 | 7/21 | Penn Yan Grape Pickers | Southern Tier League | , | |
| Offa Neal | neal--002the | 1904 | 120 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| George Needham | needha001geo | 1904 | 5/6-9/16 | Utica Pent-Ups | New York State League | , | |
| Tom Needham | needha001tho | 1904 | 5/12- | 84 g. | Boston | National League | Boston, MA |
| Lloyd Nefeau | nefeau001llo | 1904 | Carlisle | Pennsylvania League | , | ||
| William Nefzger | nefzge000wil | 1904 | 5/29-6/25+ | Eugene Blues | Oregon State League | , | |
| Edward Nehr | neher-001ed- | 1904 | +7/25+ | 22 g. | Fargo | Northern League | , |
| Fred Nehring | nehrin001fre | 1904 | 4/29-7/4 | Salem Raglands | Oregon State League | , | |
| Fred Nehring | nehrin001fre | 1904 | 2 g. | Seattle Siwashes | Pacific Coast League | , | |
| Fred Nehring | nehrin001fre | 1904 | 7/17-8/21 | Centralia Midgets | Southwest Washington League | , | |
| Fred Nehring | nehrin001fre | 1904 | 9/4 | Aberdeen Pippins | Southwest Washington League | , | |
| Norman Neighbor | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |||
| Fred Neiman | neiman001fre | 1904 | 18 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Charley Neller | 1904 | 7/24- | Camden NJ | Independent | , | ||
| Nelson | nelson019--- | 1904 | Sheffield | Tennessee-Alabama League | , | ||
| Clarence Nelson | nelson001cla | 1904 | 6/12-6/30 | Houston Wanderers | South Texas League | , | |
| Clarence Nelson | nelson001cla | 1904 | Oklahoma City Mets | Southwestern League | , | ||
| Clyde Nelson | nelson001cly | 1904 | 13 g. | Leavenworth Orioles | Missouri Valley League | , | |
| William Nelson | nelson004wil | 1904 | 17 g. | Beaumont Millionaires | South Texas League | , | |
| John Neuer | neuer-001joh | 1904 | Hazleton PA | Independent | , | ||
| Benjamin Neurither | 1904 | 6/17-7/11 | Grand Rapids Orphans | Central League | , | ||
| Harry Nevers | nevers001har | 1904 | 8/26-9/13 | Nashua | New England League | , | |
| Michael Nevins | nevins001mic | 1904 | Lodi | California State League | , | ||
| Michael Nevins | nevins001mic | 1904 | +7/4 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Ray Newcomb | 1904 | Howell MI HS | High School | , | |||
| Royal Newcomb | newcom001roy | 1904 | Howell MI HS | High School | , | ||
| Hiram Newell | newell002har | 1904 | 4/29-7/4 | Roseburg Shamrocks | Oregon State League | , | |
| Horace Newenham | newenh001hor | 1904 | no g. | Toronto Maple Leafs | Eastern League | , | |
| Horace Newenham | newenh001hor | 1904 | 5/6-6/21 | Utica Pent-Ups | New York State League | , | |
| Horace Newenham | newenh001hor | 1904 | 7/9-9/17 | Concord Marines | New England League | , | |
| Ira Newick | newick001ira | 1904 | +7/28+ | Lynn MA | Independent | , | |
| Otto Newlin | newlin001ott | 1904 | 4/20-9/20 | Indianapolis Indians | American Association | , | |
| Newman | 1904 | 6/21 | Paris Parasites/Ardmore Territorians | Texas League | , | ||
| Arthur Newman | newman001art | 1904 | Bridgeport Orators | Connecticut State League | , | ||
| John Newman | nevins001mic | 1904 | 216 ab | Baton Rouge Red Sticks | Cotton States League | , | |
| John Newman | newman001joh | 1904 | 17 g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| William Newman | newman006wil | 1904 | Knoxville | Tennessee-Alabama League | , | ||
| Harry Newmeyer | newmey001har | 1904 | 5/20- | 16 g. | Grand Forks Forkers | Northern League | , |
| Harry Newmeyer | newmey001har | 1904 | +8/4-9/3 | Waterloo Microbes | Iowa League | , | |
| Pat Newnam | newnam001pat | 1904 | , | ||||
| Al Newnham | newnha001alf | 1904 | 5/6-6/21 | Utica Pent-Ups | New York State League | , | |
| Al Newnham | newnha001alf | 1904 | 73 g. | Jacksonville Jays | South Atlantic League | , | |
| News | news--001tho | 1904 | 6/7-6/17 | Camden | Tri-State League | , | |
| Tom News | news--001tho | 1904 | Chester | Pennsylvania League | , | ||
| Tom News | news--001tho | 1904 | Hartford Senators | Connecticut State League | , | ||
| Tom News | news--001tho | 1904 | 8/11-9/10 | Wilmington Peaches | Tri-State League | , | |
| Albert Newton | newton001alb | 1904 | 4/30-7/25 | Concord Marines | New England League | , | |
| Albert Newton | newton001alb | 1904 | 7/28-9/29 | Altoona Mountaineers | Tri-State League | , | |
| Doc Newton | newton001eus | 1904 | 64 g. | Los Angeles Angels | Pacific Coast League | , | |
| Gustave Nicholi | nichol000gus | 1904 | 5/15- | Green Bay WI | Independent | , | |
| J. Wesley Nicholls | nichol001j-- | 1904 | 7/24-9/11 | San Antonio Bronchos | South Texas League | , | |
| J. Wesley Nicholls | nichol001j-- | 1904 | Galveston Sand Crabs | South Texas League | , | ||
| Simon Nicholls | nichol001sim | 1904 | Ridgely MD | Amateur | , | ||
| Nichols | nichol031--- | 1904 | 2 g. | Anniston | Tennessee-Alabama League | , | |
| Nichols | nichol028--- | 1904 | +6/16-6/30+ | Bessemer | Tennessee-Alabama League | , | |
| Art Nichols | nichol001art | 1904 | 93 g. | Rochester Bronchos | Eastern League | , | |
| C. G. Nichols | nichol001c-- | 1904 | 28 g. | Jacksonville Jays | South Atlantic League | , | |
| George Nichols | nichol001g-- | 1904 | 5 g. | Springfield Midgets | Missouri Valley League | , | |
| Kid Nichols | nichol006cha | 1904 | St. Louis | National League | St. Louis, MO | ||
| Walt Nichols | nichol001w-- | 1904 | 21 g. | Bridgeport Orators | Connecticut State League | , | |
| Al Nickell | nickel001al- | 1904 | Leavenworth Orioles | Missouri Valley League | , | ||
| Al Nickell | nickel001al- | 1904 | 9/17-9/20 | Kansas City Blues | American Association | , | |
| Harry Nickens | nicken001har | 1904 | 55 ab | Greenville Cotton Pickers | Cotton States League | , | |
| Harry Nickens | nicken001har | 1904 | 7/15-9/22 | Nashville Volunteers | Southern Association | , | |
| George Nicol | nicol-001geo | 1904 | 4/24 | Memphis Egyptians | Southern Association | , | |
| George Nicol | nicol-001geo | 1904 | 75 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| George Nicol | nicol-001geo | 1904 | Rockford Red Sox | Illinois-Indiana-Iowa League | , | ||
| Hugh Nicol | nicol-001hug | 1904 | Rockford Red Sox | Illinois-Indiana-Iowa League | , | ||
| Hugh Nicol | nicol-001hug | 1904 | Rock Island Islanders | Illinois-Indiana-Iowa League | , | ||
| Carl? Nicolar | nicola003--- | 1904 | Carlisle Indians | School | , | ||
| Carl? Nicolar | nicola003--- | 1904 | +7/1-7/29+ | Carl.-Lindler | Independent | , | |
| Carl? Nicolar | nicola003--- | 1904 | 8/11-8/18 | Harrisburg Senators | Tri-State League | , | |
| Tom Niland | niland001tom | 1904 | +7/28+ | Lynn MA | Independent | , | |
| Harry Niles | niles-001her | 1904 | 5/6-9/7 | Binghamton Bingoes | New York State League | , | |
| George Nill | nill--001geo | 1904 | 4/24-9/25 | Colorado Springs Millionaires | Western League | , | |
| George Nill | nill--001geo | 1904 | 9/27- | 15 g. | Washington | American League | Washington, DC |
| Arthur Nippert | 1904 | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |||
| Bernard Nippert | nipper001ben | 1904 | preseason | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| Bernard Nippert | nipper001ben | 1904 | Dydney OH | Independent | , | ||
| Bernard Nippert | nipper001ben | 1904 | 78 g. | Warren OH | Independent | , | |
| Ed Nist | nist--001ed- | 1904 | 29 g. | Canton OH | Independent | , | |
| Bert Noblett | noblet001j-- | 1904 | 291 ab | Monroe Hill Citys | Cotton States League | , | |
| George Noblit | noblit001geo | 1904 | 4/30-9/17 | Concord Marines | New England League | , | |
| Nolan | 1904 | 8/11 | Utica Pent-Ups | New York State League | , | ||
| J. W. Nolan | nolan-030--- | 1904 | Wheeling Stogies | Central League | , | ||
| John Nolan | nolan-030--- | 1904 | 5/8- | 5 g. | Canton OH | Independent | , |
| John Nolan | nolan-030--- | 1904 | +8/5 | Massillon OH | Independent | , | |
| John Nolan | nolan-030--- | 1904 | 8/7-9/12 | Wheeling Stogies | Central League | , | |
| Peter Nolden | nolden001pet | 1904 | no g. | Milwaukee Brewers | American Association | , | |
| Peter Nolden | nolden001pet | 1904 | 5/20- | Superior Longshoremen | Northern League | , | |
| Peter Nolden | nolden001pet | 1904 | 6/9- | Duluth White Sox | Northern League | , | |
| Peter Nolden | nolden001pet | 1904 | 19 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| Rufus Nolley | nolley001ruf | 1904 | 4/27 | Montgomery Senators | Southern Association | , | |
| Rufus Nolley | nolley001ruf | 1904 | 31 g. | Hattiesburg | Delta League | , | |
| Rufus Nolley | nolley001ruf | 1904 | +8/31+ | 11 g. | Columbia | Tennessee-Alabama League | , |
| Joe Nonemaker | nonama001jos | 1904 | 5/28-6/28 | Dayton Veterans | Central League | , | |
| Joe Nonemaker | nonama001jos | 1904 | 8/24-8/31 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Pete Noonan | noonan001pet | 1904 | Holy Cross Col. | College | , | ||
| Pete Noonan | noonan001pet | 1904 | Philadelphia | American League | Philadelphia, PA | ||
| Jerry Nops | nops--001jer | 1904 | 5/3-6/17 | Wilmington Peaches | Tri-State League | , | |
| Jerry Nops | nops--001jer | 1904 | +8/30+ | Lebanon | Tri-State League | , | |
| Jerry Nops | nops--001jer | 1904 | 9/10-9/27 | Providence Grays | Eastern League | , | |
| Alex Norcabbage | norcab001ale | 1904 | Jackson MI | Independent | , | ||
| Frank Norcom | norcom001fra | 1904 | 4/23-9/17 | Shreveport Pirates | Southern Association | , | |
| Ed Nordstrom | 1904 | +5/1+ | Frazer-Unions | Independent | , | ||
| Ed Nordstrom | 1904 | +7/27-8/29+ | Boone Coal Miners | Iowa League | , | ||
| Lou Nordyke | nordyk001lou | 1904 | 200 g. | Tacoma Tigers | Pacific Coast League | , | |
| Joseph Norton | 1904 | 5/6- | Umpire | New York State League | , | ||
| Pete Norwood | norwoo000pet | 1904 | 5/11- | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | |
| Jim Novacek | novace001jam | 1904 | 5/19- | 38 g. | Crookston Crooks | Northern League | , |
| Jim Novacek | novace001jam | 1904 | +8/10-9/1+ | Dollar Bay | Copper Country League | , | |
| Harry Noyes | noyes-001har | 1904 | 111 g. | New London Whalers | Connecticut State League | , | |
| Jack Nugent | nugent001joh | 1904 | 6/19-6/23 | Rochester Bronchos | Eastern League | , | |
| Jack Nugent | nugent001joh | 1904 | 7/11-7/15 | Manchester | New England League | , | |
| Richard Nutt | nutt--000ric | 1904 | +6/29+ | Drayton | North Dakota League | , | |
| Nydigger | 1904 | 38 g. | Niles OH | Independent | , | ||
| Nydigger | 1904 | Alliance OH | Independent | , | |||
| O'Brien | obrien087--- | 1904 | Savannah Pathfinders | South Atlantic League | , | ||
| O'Brien | obrien135--- | 1904 | 7/1-8/8 | Hornellsville Maple Cities | Southern Tier League | , | |
| O'Brien | obrien135--- | 1904 | +8/17-8/19 | Wellsville Oil Drillers | Southern Tier League | , | |
| O'Brien | obrien006j-- | 1904 | 8/18 | Binghamton Bingoes | New York State League | , | |
| O'Brien | 1904 | 7/17 | Schenectady Electricians/Scranton Miners | New York State League | , | ||
| Frank O'Brien | obrien003fra | 1904 | Sacramento | California State League | , | ||
| Frederick O'Brien | obrien001fre | 1904 | Manhattan Col. | College | , | ||
| Frederick O'Brien | obrien001fre | 1904 | Rutland | Northern New York League | , | ||
| Fritz O'Brien | obrien044--- | 1904 | 6/29-7/25 | Grand Rapids Orphans | Central League | , | |
| George O'Brien | obrien001geo | 1904 | 5/13-5/20 | Fall River Indians | New England League | , | |
| Hugh O'Brien | obrien001h-- | 1904 | 4/9 | Pratt City AL | Independent | , | |
| Hugh O'Brien | obrien001h-- | 1904 | 5/16-6/2 | Bessemer | Tennessee-Alabama League | , | |
| Hugh O'Brien | obrien001h-- | 1904 | +7/20-7/23+ | Sheffield | Tennessee-Alabama League | , | |
| Hugh O'Brien | obrien001h-- | 1904 | +8/3-8/20 | Huntsville | Tennessee-Alabama League | , | |
| Hugh O'Brien | obrien001h-- | 1904 | 9/6-9/25 | Montgomery Senators | Southern Association | , | |
| J. O'Brien | obrien006j-- | 1904 | 7/17-8/8 | Binghamton Bingoes | New York State League | , | |
| Jack O'Brien | obrien005joh | 1904 | 4/22-9/19 | Milwaukee Brewers | American Association | , | |
| Jack O'Brien | obrien006jac | 1904 | no g. | Grand Forks Forkers | Northern League | , | |
| Jack O'Brien | obrien006jac | 1904 | 1 g. | Crookston Crooks | Northern League | , | |
| James O'Brien | obrien004jam | 1904 | 4/21-9/24 | Birmingham Barons | Southern Association | , | |
| John O'Brien | obrien009joh | 1904 | 5/3-6/28 | Lawrence Colts | New England League | , | |
| John O'Brien | obrien009joh | 1904 | Derby | , | |||
| Pat O'Brien | obrien087--- | 1904 | 10 g. | Savannah Pathfinders | South Atlantic League | , | |
| Pete O'Brien | obrien001pet | 1904 | 11 g. | Indianapolis Indians | American Association | , | |
| Pete O'Brien | obrien001pet | 1904 | 4/20-9/3 | St. Paul Saints | American Association | , | |
| Thomas O'Brien | obrien003tho | 1904 | 122 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| Tom O'Brien | obrien001tom | 1904 | 4/21-6/? | Birmingham Barons | Southern Association | , | |
| Tom O'Brien | obrien001tom | 1904 | 6/15-9/25 | Montgomery Senators | Southern Association | , | |
| William O'Brien | obrien007wil | 1904 | 5/19- | 16 g. | Grand Forks Forkers | Northern League | , |
| William O'Brien | obrien011wil | 1904 | Pittsburg Coal Diggers | Missouri Valley League | , | ||
| William O'Brien | obrien007wil | 1904 | Fordham College | College | , | ||
| William O'Brien | obrien007wil | 1904 | 6/27-9/18 | Ilion Typewriters | New York State League | , | |
| William O'Brien | obrien007wil | 1904 | 8/18-8/23 | Newark Sailors | Eastern League | , | |
| John O'Connell | oconne003joh | 1904 | 119 g. | Boise Fruit Pickers | Pacific National League | , | |
| O'Connor | 1904 | 11 g. | Cairo Champions | Kentucky-Illinois-Tennessee League | , | ||
| O'Connor | oconno047--- | 1904 | 7/1-7/4 | Roseburg Shamrocks | Oregon State League | , | |
| Jack O'Connor | oconno006joh | 1904 | St. Louis | American League | St. Louis, MO | ||
| Mike O'Connor | oconno003mik | 1904 | 4/27-7/7 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Mike O'Connor | oconno003mik | 1904 | 7/8-8/15 | Umpire | Texas League | , | |
| Paddy O'Connor | oconno004pat | 1904 | 110 g. | Springfield Ponies | Connecticut State League | , | |
| Patrick O'Connor | oconno003pat | 1904 | 81 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| Willie O'Day | oday--002wil | 1904 | 4/28-5/15 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Willie O'Day | oday--002wil | 1904 | 5/18-6/5 | Eugene Blues | Oregon State League | , | |
| Willie O'Day | oday--002wil | 1904 | 6/9-7/4 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Artie O'Dea | odea--001art | 1904 | 5/19- | 62 g. | Superior Longshoremen | Northern League | , |
| Artie O'Dea | odea--001art | 1904 | 8/9- | Crookston Crooks | Northern League | , | |
| Artie O'Dea | odea--001art | 1904 | 8/12-9/5 | Lake Linden Lakers | Copper Country League | , | |
| Alfred O'Dell | odell-002alf | 1904 | 111 g. | Bridgeport Orators | Connecticut State League | , | |
| Martin O'Gara | ogara-001mar | 1904 | Villanova College | College | , | ||
| Martin O'Gara | ogara-001mar | 1904 | 14 g. | Meriden Silverites | Connecticut State League | , | |
| Martin O'Gara | ogara-001mar | 1904 | 7/27- | Addison White Sox | Southern Tier League | , | |
| Martin O'Gara | ogara-001mar | 1904 | +9/18+ | Elmira NY | Independent | , | |
| Hal O'Hagan | ohagen001har | 1904 | 6/7-9/28 | Newark Sailors | Eastern League | , | |
| Joseph O'Halloran | 1904 | +7/9+ | W. Philadelphia | MainLine | , | ||
| Bill O'Hara | ohara-002wil | 1904 | 4/29-9/19 | Toledo Mud Hens | American Association | , | |
| Dennis O'Hara | ohara-001den | 1904 | no g. | Fall River Indians | New England League | , | |
| Kid O'Hara | ohara-001jam | 1904 | 5/10-9/10 | Lawrence Colts | New England League | , | |
| Kid O'Hara | ohara-001jam | 1904 | 9/15-9/22 | Boston | National League | Boston, MA | |
| Thomas O'Hare | ohare-001tho | 1904 | 101 g. | Hartford Senators | Connecticut State League | , | |
| George O'Hearn | 1904 | 36 g. | Winnipeg Maroons | Northern League | , | ||
| Joseph O'Laughlin | 1904 | 6/18-6/25 | Utica Pent-Ups | New York State League | , | ||
| Charley O'Leary | oleary001cha | 1904 | Detroit | American League | Detroit, MI | ||
| Daniel O'Leary | oleary001dan | 1904 | 5/19- | 58 g. | Duluth White Sox | Northern League | , |
| Daniel O'Leary | oleary001dan | 1904 | 8/18-9/13 | Minneapolis Millers | American Association | , | |
| George O'Leary | oleary001geo | 1904 | Evansville River Rats | Central League | , | ||
| George O'Leary | oleary001geo | 1904 | 24+ g. | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | |
| O'Mala | 1904 | 5 g. | Akron OH | Independent | , | ||
| Michael O'Malley | omalle001mic | 1904 | 5/6-5/8 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Michael O'Malley | omalle001mic | 1904 | 443 ab | Hudson Marines | Hudson River League | , | |
| Thomas O'Mara | omara-001tho | 1904 | 5/16- | 11 g. | Bessemer | Tennessee-Alabama League | , |
| Thomas O'Mara | omara-001tho | 1904 | 45 g. | Meriden Silverites | Connecticut State League | , | |
| William O'Mara | omara-001tho | 1904 | 5/16-6/2+ | Bessemer | Tennessee-Alabama League | , | |
| O'Neil | 1904 | 11 g. | Sharon OH | Independent | , | ||
| O'Neil | oneil-039--- | 1904 | 6/29-8/12 | Penn Yan Grape Pickers | Southern Tier League | , | |
| Dan O'Neil | oneill003dan | 1904 | 4/29-9/10 | Springfield Ponies | Connecticut State League | , | |
| George O'Neil | oneil-002geo | 1904 | Mt. Carmel PA | Independent | , | ||
| Harry O'Neil | oneil-000har | 1904 | 5/13-8/26 | 3 g. | Haverhill Hustlers | New England League | , |
| Harry O'Neil | oneil-000har | 1904 | Reading | , | |||
| James O'Neil | oneil-000har | 1904 | 5/27 | Lowell Tigers | New England League | , | |
| Jack O'Neill | oneill008joh | 1904 | 51 g. | Chicago | National League | Chicago, IL | |
| James O'Neill | oneill005jam | 1904 | Lowell Tigers | New England League | , | ||
| John O'Neill | oneil-027--- | 1904 | NY-Murray Hill | Independent | , | ||
| John O'Neill | oneil-027--- | 1904 | 8/22-9/10 | Jersey City Skeeters | Eastern League | , | |
| John O'Neill | oneill004wil | 1904 | 5/7- | 17 g. | Boston | American League | Boston, MA |
| John O'Neill | oneill004wil | 1904 | 95 g. | Washington | American League | Washington, DC | |
| Mike O'Neill | oneill002mic | 1904 | 30 g. | St. Louis | National League | St. Louis, MO | |
| Peaches O'Neill | oneill002phi | 1904 | 4/16-8/4 | Cincinnati | National League | Cincinnati, OH | |
| Thomas O'Reilly | oreill001tho | 1904 | 5/6-9/18 | Utica Pent-Ups | New York State League | , | |
| Jim O'Rourke | orourk003jam | 1904 | 65 g. | Bridgeport Orators | Connecticut State League | , | |
| Jim O'Rourke | orourk003jam | 1904 | 9/22 | New York | National League | New York, NY | |
| Jimmy O'Rourke | orourk005jam | 1904 | 4/28-6/26 | Evansville River Rats | Central League | , | |
| Jimmy O'Rourke | orourk005jam | 1904 | Bridgeport Orators | Connecticut State League | , | ||
| Jimmy O'Rourke | orourk005jam | 1904 | Manchester | New England League | , | ||
| Joseph O'Rourke | orourk001jos | 1904 | 406 ab | Vicksburg Hill Billies | Cotton States League | , | |
| Tim O'Rourke | orourk003tim | 1904 | 5/7-6/25 | Waterloo Microbes | Iowa League | , | |
| Tim O'Rourke | orourk003tim | 1904 | 7/-7/ | Umpire | Iowa League | , | |
| Rebel Oakes | oakes-001enn | 1904 | 20 g. | Hattiesburg | Delta League | , | |
| Frank Oberlin | oberli002fra | 1904 | 4/28-7/19 | Fort Wayne Railroaders | Central League | , | |
| Clarence? Ochs | 1904 | Oxford | Pennsylvania League | , | |||
| George Odiorne | 1904 | +5/21+ | Charleston College | College | , | ||
| J. Odiorne | 1904 | +5/21+ | Charleston College | College | , | ||
| Fred Odwell | odwell001fre | 1904 | 4/16- | 129 g. | Cincinnati | National League | Cincinnati, OH |
| John Okey | 1904 | June | 4 g. | Boone Coal Miners | Iowa League | , | |
| George Oldham | oldham000geo | 1904 | Sharp’s Institute | Independent | , | ||
| George Oldham | oldham000geo | 1904 | U. North Carolina | College | , | ||
| Oliver | 1904 | Umpire | Texas League | , | |||
| Oliver | 1904 | 6/24-7/4 | Umpire | Texas League | , | ||
| Reginald Ollre | ollre-001rox | 1904-08 | Hous.-Firemen | Independent | , | ||
| Hank Olmsted | olmste001hen | 1904 | 5/3-9/19 | 34 g. | Columbus Senators | American Association | , |
| Sylvester Olson | olson-001syl | 1904 | 122 g. | Topeka Saints | Missouri Valley League | , | |
| Edward Opfergelt | opferg000edw | 1904 | 4/30-7/4+ | Woodstock-Olivers | Independent | , | |
| Edward Opfergelt | opferg000edw | 1904 | +7/17+ | Chic.-Gunthers | Independent | , | |
| Edward Opfergelt | opferg000edw | 1904 | +9/21+ | Woodstock-Brewery | Independent | , | |
| Walter Orbin | orbin-000wal | 1904 | 5/3-5/13 | Wilmington Peaches | Tri-State League | , | |
| Walter Orbin | orbin-000wal | 1904 | 5/23-6/17 | Camden | Tri-State League | , | |
| William Orchard | 1904 | no g. | Galveston Sand Crabs | South Texas League | , | ||
| Organ | organ-000--- | 1904 | 9/9 | Toronto Maple Leafs | Eastern League | , | |
| Jess Orndorff | orndor001jes | 1904 | 9 g. | Leavenworth Orioles | Missouri Valley League | , | |
| Jess Orndorff | orndor001jes | 1904 | 37 g. | Galveston Sand Crabs | South Texas League | , | |
| Jess Orndorff | orndor001jes | 1904 | 8/26 | Kansas City Blues | American Association | , | |
| Orr | orr---011--- | 1904 | 9/9 | Indianapolis Indians | American Association | , | |
| P. R. Orr | orr---001--- | 1904 | 5/17-6/20+ | Anniston | Tennessee-Alabama League | , | |
| P. R. Orr | orr---001--- | 1904 | +6/27-7/22+ | Sheffield | Tennessee-Alabama League | , | |
| Andreas Ortega | 1904-07 | Cuba Ls | , | ||||
| Herman Ortlieb | ortlie001her | 1904 | 4/20-5/10 | Indianapolis Indians | American Association | , | |
| Herman Ortlieb | ortlie001her | 1904 | 77 g. | Niles OH | Independent | , | |
| Ortman | ortman004--- | 1904 | Leavenworth KS | Independent | , | ||
| Arch Osborne | osborn001arc | 1904 | 5/5-8/17 | Wilmington Peaches | Tri-State League | , | |
| Joseph Osment | osment001jos | 1904 | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | ||
| Joseph Osment | osment001jos | 1904 | +6/7-6/20+ | Jackson Senators | Delta League | , | |
| Joseph Osment | osment001jos | 1904 | -7/30 | Dalton GA | Independent | , | |
| Joseph Osment | osment001jos | 1904 | +8/10-8/17 | Knoxville | Tennessee-Alabama League | , | |
| Harry Ostdiek | ostdie001hen | 1904 | 4/28-9/7 | Fort Wayne Railroaders | Central League | , | |
| Harry Ostdiek | ostdie001hen | 1904 | 9/10- | 7 g. | Cleveland | American League | Cleveland, OH |
| Champ Osteen | osteen001jam | 1904 | -5/3 | 28 g. | New York | American League | New York, NY |
| Champ Osteen | osteen001jam | 1904 | Norwich Reds | Connecticut State League | , | ||
| Champ Osteen | osteen001jam | 1904 | 9/14-9/24 | Atlanta Crackers | Southern Association | , | |
| Eddie Oswald | oswald000edd | 1904 | preseason | Springfield Midgets | Missouri Valley League | , | |
| Frank Ott | ott---002fra | 1904 | Hudson Marines | Hudson River League | , | ||
| Orval Overall | overal001orv | 1904 | 72 g. | Tacoma Tigers | Pacific Coast League | , | |
| Owens | 1904 | +8/12+ | Winnipeg Maroons | Northern League | , | ||
| Arthur Owens | owens-001art | 1904 | 20 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| Arthur Owens | owens-001art | 1904 | 5/27-8/ | Duluth White Sox | Northern League | , | |
| Arthur Owens | owens-001art | 1904 | Rockford Red Sox | Illinois-Indiana-Iowa League | , | ||
| Clarence Owens | 1904 | Umpire | Missouri Valley League | , | |||
| Red Owens | owens-003tho | 1904 | 4/23-5/10 | Shreveport Pirates | Southern Association | , | |
| Red Owens | owens-003tho | 1904 | 6/8-9/27 | York Penn Parks | Tri-State League | , | |
| Clarence Owsley | owsley001--- | 1904 | Drake Univ | College | , | ||
| Clarence Owsley | owsley001--- | 1904 | 18 g. | Topeka Saints | Missouri Valley League | , | |
| Clarence Owsley | owsley001--- | 1904 | Pittsburg Coal Diggers | Missouri Valley League | , | ||
| Clarence Owsley | owsley001--- | 1904 | 8/6-8/27 | Colorado Springs Millionaires | Western League | , | |
| Clarence Owsley | owsley001--- | 1904 | 9/1 | St. Joseph Saints | Western League | , | |
| Andy Oyler | oyler-001and | 1904 | 4/20-9/20 | Minneapolis Millers | American Association | , | |
| William Oyler | oyler-001wil | 1904 | 120 g. | Savannah Pathfinders | South Atlantic League | , | |
| Ed Pabst | pabst-001ed- | 1904 | 4/25-9/12 | Montgomery Senators | Southern Association | , | |
| Packingham | packin000--- | 1904 | 9/4 | Centralia Midgets | Southwest Washington League | , | |
| Dick Padden | padden001ric | 1904 | 132 g. | St. Louis | American League | St. Louis, MO | |
| Luis Padron | padron001lou | 1904 | Habana | Cuban Winter League | , | ||
| Albert Page | page--001alb | 1904 | 5 ab | Monroe Hill Citys | Cotton States League | , | |
| Albert Page | page--001alb | 1904 | New London Whalers | Connecticut State League | , | ||
| Billy Page | page--001wil | 1904 | 4/30-9/19 | Manchester | New England League | , | |
| George Page | page--003geo | 1904 | 4/30-7/14 | Beaumont Millionaires | South Texas League | , | |
| George Page | page--003geo | 1904 | 7/16-8/15+ | Galveston Sand Crabs | South Texas League | , | |
| Allie Paige | paige-002alb | 1904 | New London Whalers | Connecticut State League | , | ||
| George Paige | paige-001geo | 1904 | +5/29-9/1+ | Lake Linden Lakers | Copper Country League | , | |
| R. W. Paine | 1904 | Wihittinsville MA | Independent | , | |||
| Edward Painter | painte001edw | 1904 | +5/11-6/21+ | Ottumwa Standpatters | Iowa League | , | |
| Edward Painter | painte001edw | 1904 | +7/30-9/5 | Boone Coal Miners | Iowa League | , | |
| Henry Palm | palm--001hen | 1904 | Sacramento | California State League | , | ||
| Henry Palm | palm--001hen | 1904 | Lodi | California State League | , | ||
| Emilio Palomino | palomi000emi | 1904 | Carmelita | Cuban League | , | ||
| Emilio Palomino | palomi000emi | 1904 | Azul | Cuban League | , | ||
| Emilio Palomino | palomi000emi | 1904 | Almendares | Havana | , | ||
| Emil Papenfuss | papenf001emi | 1904 | Wausau WI | Independent | , | ||
| John Pappalau | pappal001joh | 1904 | 5/1-9/27 | Montreal Royals | Eastern League | , | |
| Al Pardee | pardee001alb | 1904 | 5/4-5/29 | Newark Sailors | Eastern League | , | |
| Al Pardee | pardee001alb | 1904 | 6/22-9/22 | Newark Sailors | Eastern League | , | |
| Al Pardee | 1904 | Leavenworth Orioles | Missouri Valley League | , | |||
| Frank Pardee | 1904 | Pine Bluff Lumbermen | Cotton States League | , | |||
| John Parent | parent000joh | 1904 | 7/28 | Concord Marines | New England League | , | |
| Parham | parham002--- | 1904 | 6/1 | Chattanooga | Tennessee-Alabama League | , | |
| Parker | parker020--- | 1904 | 21 g. | Hattiesburg | Delta League | , | |
| Parker | 1904 | 7/22-7/23 | Shreveport Pirates | Southern Association | , | ||
| Parker | 1904 | 7/25 | Wheeling Stogies | Central League | , | ||
| Jay Parker | parker002jay | 1904 | 4/24-9/25 | Sioux City Soos | Western League | , | |
| Richard Parker | parker001ric | 1904 | Lodi | California State League | , | ||
| Roy Parker | parker002roy | 1904 | U. of Illinois | College | , | ||
| Roy Parker | parker002roy | 1904 | 6/20-9/28 | Toronto Maple Leafs | Eastern League | , | |
| Roy Parker | parker002roy | 1904 | 8/13-8/30 | Utica Pent-Ups | New York State League | , | |
| Parkins | parkin003cha | 1904 | Johnstown Johnnies | Pennsylvania League | , | ||
| Charles Parkins | parkin003cha | 1904 | 38 g. | Hartford Senators | Connecticut State League | , | |
| Tom Parrott | parrot002tho | 1904 | 4/21-5/31 | Nashville Volunteers | Southern Association | , | |
| Tom Parrott | parrot002tho | 1904 | 6/15-7/5 | Little Rock Travelers | Southern Association | , | |
| Tom Parrott | parrot002tho | 1904 | 7/11-7/20 | Atlanta Crackers | Southern Association | , | |
| Tom Parrott | parrot002tho | 1904 | 165 ab | Monroe Hill Citys | Cotton States League | , | |
| Edward Parsons | parson001edw | 1904 | 5/17 | Bessemer | Tennessee-Alabama League | , | |
| Jim Partridge | partri001j-- | 1904 | +7/17+ | Vermillion SD | Independent | , | |
| William Partridge | partri001wil | 1904 | +7/17+ | Vermillion SD | Independent | , | |
| Dode Paskert | pasker001geo | 1904 | 4/28-9/11 | Dayton Veterans | Central League | , | |
| Dode Paskert | pasker001geo | 1904 | +10/16+ | Clev.-Franklin AC | Independent | , | |
| Tony Pastor | pastor001hen | 1904 | 4/30-9/5 | Nashua | New England League | , | |
| Jim Pastorius | pastor002jam | 1904 | 5/6-9/18 | Albany Senators | New York State League | , | |
| Patron | 1904 | +9/17+ | 6 g. | Kent OH | Independent | , | |
| Harry Pattee | pattee001har | 1904 | 44 g. | Jersey City Skeeters | Eastern League | , | |
| Ham Patterson | patter001ham | 1904 | +6/16-7/25+ | Crookston Crooks | Northern League | , | |
| Ham Patterson | patter001ham | 1904 | +8/18-8/29+ | Oskaloosa Quakers | Iowa League | , | |
| Henry Patterson | patter001hen | 1904 | 7/1-7/10 | Corsicana Oil Citys | Texas League | , | |
| Henry Patterson | patter001hen | 1904 | 7/17 | Dallas Giants | Texas League | , | |
| J. Patterson | patter004j-- | 1904 | 5/6-5/8 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Van Patterson | patter001van | 1904 | 91 g. | Niles OH | Independent | , | |
| W. W. Patterson | patter000ww- | 1904 | 5/28-5/30 | Lebanon | Tri-State League | , | |
| Will Pattison | pattis001w-- | 1904 | Baltimore Orioles | Eastern League | , | ||
| Will Pattison | pattis001w-- | 1904 | 64 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| August Paulig | paulig001aug | 1904 | 114 g. | Houston Wanderers | South Texas League | , | |
| Payne | payne-016--- | 1904 | 9 g. | Decatur | Tennessee-Alabama League | , | |
| Carl Payne | 1904 | Mt. Carmel IL | Independent | , | |||
| Fred Payne | payne-001fre | 1904 | 5/6-9/18 | Syracuse Stars | New York State League | , | |
| Joseph Payne | payne-001jos | 1904 | 5/16-7/12 | Chattanooga | Tennessee-Alabama League | , | |
| Joseph Payne | payne-001jos | 1904 | Knoxville | Tennessee-Alabama League | , | ||
| Joseph Payne | payne-001jos | 1904 | -7/30 | Dalton GA | Independent | , | |
| Wood Payne | payne-008--- | 1904 | 5/11-5/20 | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |
| John Peacock | peacoc002joh | 1904 | Hudson Marines | Hudson River League | , | ||
| Bunny Pearce | pearce001wil | 1904 | 5/14-9/6 | Evansville River Rats | Central League | , | |
| Frank Pears | pears-002fra | 1904 | 4/20-6/7 | Umpire | American Association | , | |
| Alex Pearson | pearso001ale | 1904 | +5/17-8/13+ | Altoona Mountaineers | Tri-State League | , | |
| William Pearson | pearso002wil | 1904 | 5/3-5/29 | Grand Rapids Orphans | Central League | , | |
| William Pearson | pearso002wil | 1904 | 6/9-9/11 | Dayton Veterans | Central League | , | |
| Joseph Peartree | peartr001j-- | 1904 | 5/6-9/17 | Troy Trojans | New York State League | , | |
| Charley Pease | pease-001cha | 1904 | 360 ab | Natchez Indians | Cotton States League | , | |
| Charley Pease | pease-001cha | 1904 | 10 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| Michael Peer | peer--001mic | 1904 | no g. | Toledo Mud Hens | American Association | , | |
| Michael Peer | peer--001mic | 1904 | 5/1-5/30 | Dayton Veterans | Central League | , | |
| Michael Peer | peer--001mic | 1904 | 6/8-9/6 | Evansville River Rats | Central League | , | |
| Michael Peer | peer--001mic | 1904 | 9/9-9/25 | St. Joseph Saints | Western League | , | |
| Heinie Peitz | peitz-001hen | 1904 | 84 g. | Cincinnati | National League | Cincinnati, OH | |
| Joseph Peloquin | peloqu001edm | 1904 | +5/7+ | Villanova College | College | , | |
| Joseph Peloquin | peloqu001edm | 1904 | 19 g. | Norwich Reds | Connecticut State League | , | |
| Bob Pender | pender001rob | 1904 | 407 ab | Baton Rouge Red Sticks | Cotton States League | , | |
| Pendergraft | 1904 | 5/7-5/28+ | Oskaloosa Quakers | Iowa League | , | ||
| Ike Pendleton | pendle001isa | 1904 | 111 g. | San Antonio Bronchos | South Texas League | , | |
| John Pendry | pendry001joh | 1904 | 45 g. | Kent OH | Independent | , | |
| Art Pennell | pennel001art | 1904 | 4/20-9/20 | Milwaukee Brewers | American Association | , | |
| George Pennington | pennin002geo | 1904 | 5/7-9/5 | Boone Coal Miners | Iowa League | , | |
| William Peoples | people001wil | 1904 | 7/24- | Camden NJ | Independent | , | |
| Joseph Percival | perciv001jos | 1904 | Springfield Hustlers | Illinois-Indiana-Iowa League | , | ||
| Joseph Percival | perciv001jos | 1904 | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | ||
| Joseph Percival | perciv001jos | 1904 | 31 g. | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |
| Joseph Percival | perciv001jos | 1904 | +6/28-8/3+ | Sheffield | Tennessee-Alabama League | , | |
| Fred Perkins | perkin001fre | 1904 | 5/3-5/17 | Camden | Tri-State League | , | |
| Fred Perkins | perkin001fre | 1904 | 7/24- | Camden NJ | Independent | , | |
| I. C. Perkins | 1904 | Wheeling Stogies | Central League | , | |||
| Ray Perkins | perkin001ray | 1904 | New Haven Blues | Connecticut State League | , | ||
| Ray Perkins | perkin001ray | 1904 | Meriden Silverites | Connecticut State League | , | ||
| Tate Perkins | perkin013--- | 1904 | +5/28+ | 16 g. | Fort Scott Giants | Missouri Valley League | , |
| Thomas Perkins | perkin001tho | 1904 | 5/16-6/30+ | Bessemer | Tennessee-Alabama League | , | |
| Blonde Perrin | 1904 | +5/20+ | Salem-YMCA | Independent | , | ||
| Bull Perrine | perrin001fre | 1904 | Oakland | California State League | , | ||
| Bull Perrine | perrin001fre | 1904 | San Francisco | California State League | , | ||
| John Perrine | perrin002joh | 1904 | 124 g. | Springfield Midgets | Missouri Valley League | , | |
| John Perrine | perrin002joh | 1904 | 9/17-9/20 | Kansas City Blues | American Association | , | |
| Red Perry | perry-001e-- | 1904 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | ||
| Dutch Persch | persch001abn | 1904 | 113 g. | Springfield Midgets | Missouri Valley League | , | |
| Archie Persons | person001arc | 1904-06 | U. Wisconsin | College | , | ||
| Eddie Persons | person001edw | 1904 | 65 g. | Jacksonville Jays | South Atlantic League | , | |
| Peterson | peters067--- | 1904 | 9/11 | Colorado Springs Millionaires | Western League | , | |
| Peterson | peters003--- | 1904 | San Francisco | California State League | , | ||
| Bob Peterson | peters005rob | 1904 | 5/12-9/19 | Fall River Indians | New England League | , | |
| Dave Peterson | 1904 | +6/12+ | Chanute KS | Independent | , | ||
| Dave Peterson | 1904 | Chanute | , | ||||
| Jay Peterson | 1904 | no g. | Utica Pent-Ups | New York State League | , | ||
| Robert Pettifier | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |||
| Pettigrew | 1904 | Sedalia Goldbugs | Missouri Valley League | , | |||
| Jim Pettigrew | pettig001jim | 1904 | Guthrie Blues | Southwestern League | , | ||
| Andrew Pettit | petit-001and | 1904 | 34+ g. | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |
| George Pfanmiller | pfanmi001geo | 1904 | 5/1-9/27 | Jersey City Skeeters | Eastern League | , | |
| W. L. Pfeiffer | pfeiff001w-- | 1904 | 4/28-6/7 | Dayton Veterans | Central League | , | |
| W. L. Pfeiffer | pfeiff001w-- | 1904 | 41 g. | Coshocton OH | Independent | , | |
| Dan Pfenninger | pfenni001dan | 1904 | 4/21-9/25 | Umpire | Southern Association | , | |
| A. C. Pfiester | 1904 | 4/27-5/5 | Dallas Giants | Texas League | , | ||
| Jack Pfiester | pfiest001joh | 1904 | 5/13-9/24 | Omaha Rangers | Western League | , | |
| Jack Pfiester | pfiest001joh | 1904 | 3 g. | Pittsburgh | National League | Pittsburgh, PA | |
| George Phalen | phalen001geo | 1904 | St. Bonaventure | College | , | ||
| George Phalen | phalen001geo | 1904 | 8/10-8/12 | Penn Yan Grape Pickers | Southern Tier League | , | |
| Martin Phelan | phelan001mar | 1904 | Hudson Marines | Hudson River League | , | ||
| Ralph Philbrick | philbr001ral | 1904 | 5/8-9/4 | Hoquiam Perfect Gentlemen | Southwest Washington League | , | |
| Bill Phillips | philli005wil | 1904 | 4/29-9/20 | Indianapolis Indians | American Association | , | |
| James Phillips | philli012jam | 1904 | Sunbury PA | Independent | , | ||
| O. S. Philpot | 1904 | 5/5-5/28 | Wheeling Stogies | Central League | , | ||
| Harry Phipps | phipps001har | 1904 | 5/15-7/24 | Hoquiam Perfect Gentlemen | Southwest Washington League | , | |
| Harry Phipps | phipps001har | 1904 | 7/31-9/4 | Olympia Senators | Southwest Washington League | , | |
| Thomas Phoenix | phoeni001tho | 1904 | 5/6-7/26+ | Oskaloosa Quakers | Iowa League | , | |
| Bill Phyle | phyle-002wil | 1904 | Johnstown PA | Independent | , | ||
| Bill Phyle | phyle-002wil | 1904 | 44 g. | Youngs-OhioWorks | Independent | , | |
| Wiley Piatt | piatt-001wil | 1904 | 4/21-9/24 | Nashville Volunteers | Southern Association | , | |
| Ollie Pickering | picker001oli | 1904 | 124 g. | Philadelphia | American League | Philadelphia, PA | |
| Dave Pickett | picket003dav | 1904 | 4/28-5/29 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Dave Pickett | picket003dav | 1904 | 5/30-7/18 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Dave Pickett | picket003dav | 1904 | 87/19-9/11 | Dayton Veterans | Central League | , | |
| Charles Piepho | piepho001c-- | 1904 | +5/22+ | Loui.-All Pros | Independent | , | |
| Charles Piepho | piepho001c-- | 1904 | +7/17+ | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |
| Charles Piepho | piepho001c-- | 1904 | +8/5+ | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| Charles Piepho | piepho001c-- | 1904 | +10/9+ | Loui.-All Pros | Independent | , | |
| Bemis Pierce | 1904 | Univ. Wisconsin | College | , | |||
| Elmer Pierce | pierce001elm | 1904 | 5/28-9/19 | St. Paul Saints | American Association | , | |
| J. G. Pinkerton | pinker000jg- | 1904 | Iola Gasbags | Missouri Valley League | , | ||
| Ed Pinnance | pinnan001edw | 1904 | 5/5-6/18 | Wilmington Peaches | Tri-State League | , | |
| Ed Pinnance | pinnan001edw | 1904 | 7/14-7/15 | Nashua | New England League | , | |
| Ed Pinnance | pinnan001edw | 1904 | 7/29-9/17 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Frank Piper | piper-001fra | 1904 | no g. | Ilion Typewriters | New York State League | , | |
| Frank Piper | piper-001fra | 1904 | 5/3-6/22 | Wilmington Peaches | Tri-State League | , | |
| Frank Piper | piper-001fra | 1904 | 10 g. | Warren OH | Independent | , | |
| Ralph Pitts | 1904 | U. of Illinois | College | , | |||
| Ralph Pitts | 1904 | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |||
| Homer Plake | plake-001hom | 1904 | 5/7-5/14 | Waterloo Microbes | Iowa League | , | |
| Homer Plake | plake-001hom | 1904 | 5/18-9/5 | Ottumwa Standpatters | Iowa League | , | |
| Ira Plank | plank-001ira | 1904 | Norwich Reds | Connecticut State League | , | ||
| Forrest Plass | plass-001for | 1904 | 388 ab | Vicksburg Hill Billies | Cotton States League | , | |
| Harry Platt | platt-001har | 1904 | Oakland | California State League | , | ||
| Harry Platt | platt-001har | 1904 | Lodi | California State League | , | ||
| Eddie Pleiss | pleiss001edw | 1904 | 5/10-9/30 | Lebanon | Tri-State League | , | |
| Eddie Pleiss | pleiss001edw | 1904 | Lodi | California State League | , | ||
| Eddie Pleiss | pleiss001edw | 1904 | Vicksburg Hill Billies | Cotton States League | , | ||
| Thomas Pleiss | 1904 | , | |||||
| Plummer | plumme011--- | 1904 | 8/11 | Spokane Indians | Pacific National League | , | |
| Plummer | plumme001--- | 1904 | Lodi | California State League | , | ||
| Thomas Plummer | plumme001tho | 1904 | 4/28-5/29 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Thomas Plummer | plumme001tho | 1904 | 5/30-7/30 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Thomas Plummer | plumme001tho | 1904 | 7/31-9/9 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Thomas Plummer | plumme001tho | 1904 | 8/17-8/26 | Warren OH | Independent | , | |
| Tom Plunkett | plunke001emm | 1904 | Fordham Univ | College | , | ||
| Tom Plunkett | plunke001emm | 1904 | Norwich Reds | Connecticut State League | , | ||
| Walter Plymat | plymat001--- | 1904 | +6/16-6/20+ | Superior Longshoremen | Northern League | , | |
| Dee Poindexter | poinde001dee | 1904 | 4/27-8/15 | Fort Worth Panthers | Texas League | , | |
| Phillip Poland | poland002phi | 1904 | Nashua | New England League | , | ||
| Phillip Poland | poland002phi | 1904 | 9/6-9/9 | Providence Grays | Eastern League | , | |
| Lou Polchow | polcho001lou | 1904 | 4/28-6/2 | Montgomery Senators | Southern Association | , | |
| Lou Polchow | polcho001lou | 1904 | 36 g. | Augusta Tourists | South Atlantic League | , | |
| Lou Polchow | polcho001lou | 1904 | Macon Highlanders | South Atlantic League | , | ||
| Henry Pollock | polloc001hen | 1904 | 108 g. | Beaumont Millionaires | South Texas League | , | |
| Henry Pollock | polloc001hen | 1904 | San Antonio Bronchos | South Texas League | , | ||
| Jack Pollock | polloc001joh | 1904 | preseason | Terre Haute Hottentots | Central League | , | |
| Jack Pollock | polloc001joh | 1904 | +5/25-6/28+ | Oskaloosa Quakers | Iowa League | , | |
| Poole | 1904 | 9 g. | Newark OH | Independent | , | ||
| Ed Poole | poole-001edw | 1904 | - 7/27 | 25 g. | Brooklyn | National League | Brooklyn, NY |
| M. Poole | 1904 | Wheeling Stogies | Central League | , | |||
| Pope | 1904 | 18 g. | Canton OH | Independent | , | ||
| Fred Popkay | popkay001fre | 1904 | +6/6-7/31+ | Umpire | New York State League | , | |
| Bill Popp | popp--001wil | 1904 | 5/11-6/1 | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | |
| C.R. Porter | porter004c-- | 1904 | 7/9-7/17 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Charles Porter | porter003c-- | 1904 | 106 g. | Springfield Midgets | Missouri Valley League | , | |
| Samuel Posey | 1904 | +4/14+ | U. So. Carolina | College | , | ||
| Lew Post | post--001lew | 1904 | no g. | Colorado Springs Millionaires | Western League | , | |
| Lew Post | post--001lew | 1904 | Toledo Mud Hens | American Association | , | ||
| Potts | 1904 | 23 g. | Lancaster OH | Independent | , | ||
| Potts | 1904 | Kent OH | Independent | , | |||
| Potts | 1904 | Tri-State League | , | ||||
| J. Frank Potts | potts-002j-- | 1904 | 49+ g. | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| Bill Pounds | pounds001jea | 1904 | 5/17-9/17 | Binghamton Bingoes | New York State League | , | |
| Abner Powell | powell001abn | 1904 | 4/21-9/25 | Atlanta Crackers | Southern Association | , | |
| Albert Powell | powell001b-- | 1904 | 5/7-9/5 | Boone Coal Miners | Iowa League | , | |
| B. W. Powell | powell001b-- | 1904 | 33 g. | Boone Coal Miners | Iowa League | , | |
| Fred. Powell | 1904 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |||
| J. D. Powell | powell000jd- | 1904 | +8/1+ | Misso.-Giants | Independent | , | |
| Jack Powell | powell007joh | 1904 | New York | American League | New York, NY | ||
| Edward Powers | powers001edw | 1904 | 5/4-5/25 | Fort Wayne Railroaders | Central League | , | |
| Edward Powers | powers001edw | 1904 | 5/26-5/27 | Evansville River Rats | Central League | , | |
| Edward Powers | powers001edw | 1904 | +7/14+ | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |
| Edward Powers | powers001edw | 1904 | +8/17-9/4 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| Lefty Powers | powers016--- | 1904 | +6/27-6/28+-7/ | Sheffield | Tennessee-Alabama League | , | |
| Pratt | 1904 | 12 g. | Alliance OH | Independent | , | ||
| E. Pratt | pratt-001e-- | 1904 | 90 g. | Jacksonville Jays | South Atlantic League | , | |
| E. P. Preble | peble-001e-- | 1904 | 4/28-5/15 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| E. P. Preble | peble-001e-- | 1904 | 5/18-5/30 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Albert Pregont | pregon000alb | 1904 | Wausau WI | Independent | , | ||
| Del Pregont | pregon000del | 1904 | Wausau WI | Independent | , | ||
| Syl Preston | 1904 | Cornell Univ | College | , | |||
| Walt Preston | presto002wal | 1904 | 5/8-5/20 | Sioux City Soos | Western League | , | |
| Howard Price | price-001how | 1904 | Enid Evangelists | Southwestern League | , | ||
| John Price | 1904 | 7/24- | Camden NJ | Independent | , | ||
| Norman Price | price-001how | 1904 | Enid Evangelists | Southwestern League | , | ||
| Ted Price | price-001e-- | 1904 | 4/30-9/12 | Wheeling Stogies | Central League | , | |
| Prince | 1904 | 22 g. | Coshocton OH | Independent | , | ||
| Arthur Prior | 1904 | Colorado Col | College | , | |||
| Arthur Prior | 1904 | no g. | Colorado Springs Millionaires | Western League | , | ||
| Billy Prout | prout-002wil | 1904 | 4/23-5/16 | Shreveport Pirates | Southern Association | , | |
| Billy Prout | prout-002wil | 1904 | +6/2-8/20 | Huntsville | Tennessee-Alabama League | , | |
| Billy? Pugh | pugh--005--- | 1904 | 8/2- | Wellsville Oil Drillers | Southern Tier League | , | |
| Raymond Pulse | pulse-001ray | 1904 | Anderson IN | Independent | , | ||
| Nate Pulsifer | pulsif001nat | 1904 | 4/30-9/17 | Concord Marines | New England League | , | |
| Frederick Purcell | purcel001the | 1904 | 5/2-7/2 | Wheeling Stogies | Central League | , | |
| Frederick Purcell | purcel001the | 1904 | Lancaster | Ohio State League | , | ||
| Jesse Purnell | purnel001jes | 1904 | +5/7+ | Roebling | Independent | , | |
| Jesse Purnell | purnel001jes | 1904 | 8/24- | Camden NJ | Independent | , | |
| Jesse Purnell | purnel001jes | 1904 | 9/9 | Wilmington Peaches | Tri-State League | , | |
| Jesse Purnell | purnel001jes | 1904 | 10/1-10/8 | Philadelphia | National League | Philadelphia, PA | |
| Purtell | 1904 | 24 g. | Newark OH | Independent | , | ||
| Billy Purtell | purtel002wil | 1904 | 50 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| Billy Purtell | purtel002wil | 1904 | 9/18-9/20 | Columbus Senators | American Association | , | |
| Ambrose Puttmann | puttma001amb | 1904 | 9 g. | New York | American League | New York, NY | |
| Ambrose Puttmann | puttma001amb | 1904 | 6/27-7/22 | Providence Grays | Eastern League | , | |
| Ambrose Puttmann | puttma001amb | 1904 | New York | American League | New York, NY | ||
| William Pylant | pylant001w-- | 1904 | 5/16-5/24+ | Huntsville | Tennessee-Alabama League | , | |
| William Pylant | pylant001w-- | 1904 | Columbia | Tennessee-Alabama League | , | ||
| William Pylant | pylant001w-- | 1904 | +6/18-6/23+ | Sheffield | Tennessee-Alabama League | , | |
| William Pylant | pylant001w-- | 1904 | +6/30-7/6+ | Huntsville | Tennessee-Alabama League | , | |
| William Pylant | pylant001w-- | 1904 | 7/16-9/24 | Birmingham Barons | Southern Association | , | |
| Tommy Queeney | 1904 | 5/5-5/21 | Umpire | Hudson River League | , | ||
| Arthur Queisser | quisse001art | 1904 | 4/27-8/2 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Arthur Queisser | quisse001art | 1904 | 8/5-8/15 | Fort Worth Panthers | Texas League | , | |
| Walter Queisser | queiss001wal | 1904 | 9/8-9/10 | Indianapolis Indians | American Association | , | |
| Walter Queisser | queiss001wal | 1904 | +9/8+ | Indianapolis Indians | American Association | , | |
| Eddie Quick | quick-001edw | 1904 | Salt Lake City Elders | Pacific National League | , | ||
| Eddie Quick | quick-001edw | 1904 | Butte Miners/Fruit Pickers | Pacific National League | , | ||
| Eddie Quick | quick-001edw | 1904 | 7/4-9/25 | Omaha Rangers | Western League | , | |
| Harry Quick | quick-001har | 1904 | 5/8-9/4 | Centralia Midgets | Southwest Washington League | , | |
| Arthur Quiesser | 1904 | 4/27-8/2 | Paris Parasites/Ardmore Territorians | Texas League | , | ||
| Arthur Quiesser | 1904 | 8/5-8/15 | Fort Worth Panthers | Texas League | , | ||
| Frank Quigg | quigg-001fra | 1904 | 5/6-9/5 | Umpire | Iowa League | , | |
| Arthur Quigley | quigle002art | 1904 | 5/9-6/7+ | Boone Coal Miners | Iowa League | , | |
| Frank Quigley | quigle001fra | 1904 | 109 g. | Hartford Senators | Connecticut State League | , | |
| Frank Quigley | quigle001fra | 1904 | Meriden Silverites | Connecticut State League | , | ||
| Lee Quillin | quille001leo | 1904 | 5/19-8/6 | Duluth White Sox | Northern League | , | |
| Larry Quinlan | quinla001law | 1904 | 4/20-9/19 | Louisville Colonels | American Association | , | |
| Bobby Quinn | quinn-005rob | 1904-15 | Columbus | American Association | , | ||
| Ed. Quinn | 1904 | 5/20 | Schenectady Electricians/Scranton Miners | New York State League | , | ||
| Frank Quinn | quinn-006fra | 1904 | 4/28-5/28 | Evansville River Rats | Central League | , | |
| Frank Quinn | quinn-006fra | 1904 | 6/18-7/1 | South Bend Greens | Central League | , | |
| Jack Quinn | quinn-004joh | 1904 | 6/29-9/9 | Addison White Sox | Southern Tier League | , | |
| Johnnie Quinn | 1904 | +6/9+ | Umpire | South Atlantic League | , | ||
| Tad Quinn | quinn-001cla | 1904 | 5/5 | Newark Sailors | Eastern League | , | |
| Tad Quinn | quinn-001cla | 1904 | New Haven Blues | Connecticut State League | , | ||
| Thomas Quinn | quinn-001tho | 1904 | 35 g. | Macon Highlanders | South Atlantic League | , | |
| W. J. Quinn | quinn-003bob | 1904 | Zanesville OH | ProtAssn | , | ||
| Teddy Radcliffe | radcli001c-- | 1904 | 4/26-8/14 | Colorado Springs Millionaires | Western League | , | |
| J. Radford | radfor001j-- | 1904 | 4/28-7/4 | Eugene Blues | Oregon State League | , | |
| J. E. Radis | radis-000je- | 1904 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | ||
| Raferty | 1904 | Greenfield MA | Independent | , | |||
| Jack Rafter | rafter001joh | 1904 | 5/6-9/17 | Troy Trojans | New York State League | , | |
| Jack Rafter | rafter001joh | 1904 | Pittsburgh | National League | Pittsburgh, PA | ||
| Tom Raftery | rafter001tho | 1904 | 4/30-9/17 | Haverhill Hustlers | New England League | , | |
| Ragan | ragan-001--- | 1904 | Huntsville | Tennessee-Alabama League | , | ||
| Arthur Ragan | reagan001art | 1904 | 4/28-8/9 | Dallas Giants | Texas League | , | |
| Arthur Ragan | reagan001art | 1904 | 8/14-9/22 | Birmingham Barons | Southern Association | , | |
| James Ragan | 1904 | Umpire | Missouri Valley League | , | |||
| James Ragan | 1904 | Umpire | Western Association | , | |||
| Benjamin Ragsdale | ragsda001ben | 1904 | Ardmore IT | Independent | , | ||
| Benjamin Ragsdale | ragsda001ben | 1904 | 8/5-8/15 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Benjamin Ragsdale | ragsda001ben | 1904 | Dallas Giants | Texas League | , | ||
| Joe Raidy | raidy-001jos | 1904 | 5/6-9/18 | Ilion Typewriters | New York State League | , | |
| Jack Raih | raih--001joh | 1904 | 5/15-8/ | Green Bay WI | Independent | , | |
| Rall | 1904 | 7/25 | Paris Parasites/Ardmore Territorians | Texas League | , | ||
| William Ramberger | ramber001--- | 1904 | 22 g. | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |
| Al Rambo | 1904 | 8/27- | Camden NJ | Independent | , | ||
| John Ramey | ramey-002joh | 1904 | 6/11-7/1 | Sioux City Soos | Western League | , | |
| John Ramey | ramey-002joh | 1904 | +7/19-8/31+ | Burlington River Rats | Iowa League | , | |
| George Ramsey | ramsey001geo | 1904 | Janesville WI | Independent | , | ||
| George Ramsey | ramsey001geo | 1904 | La Crosse WI | Independent | , | ||
| George Ramsey | ramsey002geo | 1904 | 4/5-6/21 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| George Ramsey | ramsey002geo | 1904 | 7/13-9/11 | Binghamton Bingoes | New York State League | , | |
| Hank Ramsey | ramsey001hen | 1904 | 5/13-9/18 | Kingston Colonials | Hudson River League | , | |
| Toad Ramsey | ramsey001toa | 1904 | Umpire | Central League | , | ||
| Harry Rand | rand--002--- | 1904 | Leavenworth Orioles | Missouri Valley League | , | ||
| Randall | 1904 | Harvard Univ. | College | , | |||
| Newt Randall | randal001new | 1904 | 5/19- | 67 g. | Duluth White Sox | Northern League | , |
| Newt Randall | randal001new | 1904 | +8/12-8/16+ | Portage Lake | Copper Country League | , | |
| Randell | randel001--- | 1904 | 17 g. | Canton | Delta League | , | |
| Randolph | randol005--- | 1904 | Washburn College | College | , | ||
| Randolph | randol005--- | 1904 | Joplin Miners | Missouri Valley League | , | ||
| Randolph | randol005--- | 1904 | Topeka Saints | Missouri Valley League | , | ||
| William Rankin | rankin001wil | 1904 | 357 ab | Natchez Indians | Cotton States League | , | |
| Edward Ransick | ransic001edw | 1904 | Charleston WV | Independent | , | ||
| Frederick Ransome | ransom001fra | 1904 | Rock Island Islanders | Illinois-Indiana-Iowa League | , | ||
| Rapp | rapp--022--- | 1904 | 8/23- | Haverhill Hustlers | New England League | , | |
| Rapp | rapp--022--- | 1904 | -8/26 | Lawrence Colts | New England League | , | |
| Charles Rapp | rapp--001cha | 1904 | +5/12+ | Mt. Vernon OH | Independent | , | |
| Louis Rapp | rapp--001lou | 1904 | 4/29-9/5 | Toronto Maple Leafs | Eastern League | , | |
| William Rapp | 1904 | Norwich Reds | Connecticut State League | , | |||
| William Rapps | rapps-001wil | 1904 | 114 g. | Leavenworth Orioles | Missouri Valley League | , | |
| Jimmy Raub | raub--001jam | 1904 | Newburgh Taylor-mades | Hudson River League | , | ||
| Jimmy Raub | raub--001jam | 1904 | 7/1-7/13 | Hornellsville Maple Cities | Southern Tier League | , | |
| Tommy Raub | raub--001tho | 1904 | 4/29-8/28 | Toronto Maple Leafs | Eastern League | , | |
| John Ray | ray---006joh | 1904 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | ||
| Thomas Ray | ray---002tho | 1904 | 68 g. | Savannah Pathfinders | South Atlantic League | , | |
| Thomas Ray | ray---002tho | 1904 | Augusta Tourists | South Atlantic League | , | ||
| Fred Raymer | raymer001fre | 1904 | 114 g. | Boston | National League | Boston, MA | |
| Fred Raymer | raymer001fre | 1904 | 19 g. | Tacoma Tigers | Pacific Coast League | , | |
| Bugs Raymond | raymon001art | 1904 | +5/17+ | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| Bugs Raymond | raymon001art | 1904 | +6/13-9/5 | Waterloo Microbes | Iowa League | , | |
| Bugs Raymond | raymon001art | 1904 | 9/23 | Detroit | American League | Detroit, MI | |
| Tealey Raymond | raymon002fra | 1904 | Los Angeles Angels | Pacific Coast League | , | ||
| Tealey Raymond | raymon002fra | 1904 | 5/27-6/19 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Tealey Raymond | raymon002fra | 1904 | Portland Browns | Pacific Coast League | , | ||
| Tealey Raymond | raymon002fra | 1904 | 97 g. | San Jose | California State League | , | |
| Tealey Raymond | raymon002fra | 1904 | Stockton | California State League | , | ||
| J. Read | 1904 | Decatur | Tennessee-Alabama League | , | |||
| William Read | read--000bil | 1904 | 9/27 | Toronto Maple Leafs | Eastern League | , | |
| Charles Reading | readin001cha | 1904 | 4/24-8/18 | Toledo Mud Hens | American Association | , | |
| Reagan | reagan008--- | 1904 | Decatur | Tennessee-Alabama League | , | ||
| Steve Reagan | reagan001ste | 1904 | 118 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| George Ream | ream--001geo | 1904 | 5/3-9/11 | Fort Wayne Railroaders | Central League | , | |
| Phil Reardon | reardo001phi | 1904 | 28 g. | Columbia Skyscrapers | South Atlantic League | , | |
| William Rebscher | rebsch001wil | 1904 | 23 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Wallace Reddick | reddic001wal | 1904 | 37 g. | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | |
| J. Redmond | redmon003j-- | 1904 | 5/7-6/8+ | Ottumwa Standpatters | Iowa League | , | |
| J. Redmond | redmon003j-- | 1904 | 6/23-7/4 | Umpire | Iowa League | , | |
| James Redmond | redmon003jam | 1904 | 5/6-9/5 | Ottumwa Standpatters | Iowa League | , | |
| Benno Reeb | 1904 | Hamilton OH | Independent | , | |||
| Reed | reed--039--- | 1904 | 36 g. | Jackson Senators | Delta League | , | |
| Reed | 1904 | 6/20-6/23 | Corsicana Oil Citys | Texas League | , | ||
| Reed | 1904 | 86 g. | Niles OH | Independent | , | ||
| Ed Reed | 1904 | Crookston Crooks | Northern League | , | |||
| Edward Reed | reed--001edw | 1904 | 4/29-5/27 | Terre Haute Hottentots | Central League | , | |
| Edward Reed | reed--001edw | 1904 | Rock Island Islanders | Illinois-Indiana-Iowa League | , | ||
| George Reed | reed--003geo | 1904 | 44 ab | Pine Bluff Lumbermen | Cotton States League | , | |
| George Reed | reed--003geo | 1904 | 6/9-6/15 | San Antonio Bronchos | South Texas League | , | |
| Ray Reed | reed--002ray | 1904 | 4/29-7/4 | Roseburg Shamrocks | Oregon State League | , | |
| Thomas Reed | reed--001tho | 1904 | 49 g. | Pittsburg Coal Diggers | Missouri Valley League | , | |
| Zeke Reed | reed--000zek | 1904 | Helena MT | Independent | , | ||
| C. C. Reeder | 1904 | Wheeling Stogies | Central League | , | |||
| Grover Reeder | reeder002gro | 1904 | Pine Bluff Lumbermen | Cotton States League | , | ||
| Grover Reeder | reeder002gro | 1904 | 10 ab | Baton Rouge Red Sticks | Cotton States League | , | |
| Grover Reeder | reeder002gro | 1904 | 14 g. | Brookhaven | Delta League | , | |
| Grover Reeder | reeder002gro | 1904 | Cumberland MD | Independent | , | ||
| Henry Rees | rees--000hen | 1904 | Minn.-Toosers | Amateur | , | ||
| Ralph Reeve | 1904 | Lynn MA | Independent | , | |||
| Reeves | 1904 | +5/10+ | Burlington River Rats | Iowa League | , | ||
| Billy Reeves | reeves001wil | 1904 | 5/8-7/10 | Hoquiam Perfect Gentlemen | Southwest Washington League | , | |
| Billy Reeves | reeves001wil | 1904 | 7/24 | Aberdeen Pippins | Southwest Washington League | , | |
| Billy Reeves | reeves001wil | 1904 | 8/28 | Centralia Midgets | Southwest Washington League | , | |
| William Reid | 1904 | Scammon KS | Independent | , | |||
| Bill Reidy | reidy-001wil | 1904 | - 7/1 | 11 g. | Brooklyn | National League | Brooklyn, NY |
| Bill Reidy | reidy-001wil | 1904 | 7/29-9/17 | Louisville Colonels | American Association | , | |
| Bob Reigler | 1904 | +8/6+ | No. Braddock | Independent | , | ||
| Reilly | 1904 | Poughkeepsie Colts | Hudson River League | , | |||
| Reilly | 1904 | 30 g. | Canton OH | Independent | , | ||
| Charlie Reilly | reilly003cha | 1904 | 112 g. | Spokane Indians | Pacific National League | , | |
| Josh Reilly | reilly002wil | 1904 | San Jose | California State League | , | ||
| Reinacher | reinac001--- | 1904 | 5/9-5/14 | Utica Pent-Ups | New York State League | , | |
| Senter Reiney | rainey001sen | 1904 | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | ||
| Phil Reisinger | reisin001phi | 1904 | 346 ab | Greenville Cotton Pickers | Cotton States League | , | |
| Doc Reisling | reisli001fra | 1904 | 4/20-7/26 | Toledo Mud Hens | American Association | , | |
| Doc Reisling | reisli001fra | 1904 | 7/30-8/30 | New Orleans Pelicans | Southern Association | , | |
| Doc Reisling | reisli001fra | 1904 | 9/10- | 7 g. | Brooklyn | National League | Brooklyn, NY |
| George Reitz | reitz-001geo | 1904 | 4/27-8/15 | Fort Worth Panthers | Texas League | , | |
| Henry Reitz | reitz-001hen | 1904 | 4/28-5/8 | Eugene Blues | Oregon State League | , | |
| Henry Reitz | reitz-001hen | 1904 | 5/11- | San Francisco Seals | Pacific Coast League | , | |
| Henry Reitz | reitz-001hen | 1904 | 7/26-9/12 | Milwaukee Brewers | American Association | , | |
| John Reitz | reitz-001joh | 1904 | Fort Dodge Gypsum Eaters | Iowa League | , | ||
| Clarence Relf | reid--001r-- | 1904 | 75 g. | Yazoo City Zoos | Delta League | , | |
| Butch Rementer | rement001wil | 1904 | 5/3-6/12 | Camden | Tri-State League | , | |
| Butch Rementer | rement001wil | 1904 | 6/22-9/10 | Wilmington Peaches | Tri-State League | , | |
| Butch Rementer | rement001wil | 1904 | +10/5+ | Trenton YMCA | Independent | , | |
| Butch Rementer | rement001wil | 1904 | 10/8 | Philadelphia | National League | Philadelphia, PA | |
| Arthur Reuber | 1904-05 | Northwestern U. | College | , | |||
| Ed Reulbach | reulba001edw | 1904 | Notre Dame Univ | College | , | ||
| Ed Reulbach | reulba001edw | 1904 | Sedalia Goldbugs | Missouri Valley League | , | ||
| Ed Reulbach | reulba001edw | 1904 | Burlington | Northern New York League | , | ||
| John Reuther | reuthe001joh | 1904 | 5/14-9/2 | Galveston Sand Crabs | South Texas League | , | |
| Reynolds | reynol017--- | 1904 | 6/2-6/14+ | Anniston | Tennessee-Alabama League | , | |
| Reynolds | 1904 | 15 g. | Alliance OH | Independent | , | ||
| Hal Reynolds | reynol002h-- | 1904 | +5/9-5/12+ | Burlington River Rats | Iowa League | , | |
| Jesse Reynolds | reynol001jes | 1904 | 49 g. | Charleston Sea Gulls | South Atlantic League | , | |
| Jesse Reynolds | reynol001jes | 1904 | +7/2+ | Columbia Skyscrapers | South Atlantic League | , | |
| Randolph Reynolds | reynol017--- | 1904 | Auburn Univ. | College | , | ||
| Randolph Reynolds | reynol017--- | 1904 | 6/2-6/14+ | Anniston | Tennessee-Alabama League | , | |
| Tommy Reynolds | reynol001tho | 1904 | 5/6-6/14 | Boone Coal Miners | Iowa League | , | |
| Edgar Rhodes | rhodes004dus | 1904 | +7/4+ | Linc.-Creameries | Independent | , | |
| Frank Rhoton | rhoton001fra | 1904 | 5/16-8/3 | Knoxville | Tennessee-Alabama League | , | |
| William Riccius | ricciu001wil | 1904 | 4/30-8/26 | Fall River Indians | New England League | , | |
| Arthur Rice | rice--001art | 1904 | Kingston Colonials | Hudson River League | , | ||
| Laurence Rice | rice--001law | 1904 | 6/29-9/10 | Elmira | Southern Tier League | , | |
| Thomas Richards | richar002tho | 1904 | 20+ g. | Cairo Champions | Kentucky-Illinois-Tennessee League | , | |
| Richardson | richar064--- | 1904 | 7/1-8/19 | Hornellsville Maple Cities | Southern Tier League | , | |
| Albert Richardson | richar001a-- | 1904 | 8 g. | Corsicana Oil Citys | Texas League | , | |
| Albert Richardson | richar001a-- | 1904 | 7/4-7/21 | Corsicana Oil Citys | Texas League | , | |
| Bill Richardson | richar006wil | 1904 | 5/3-9/11 | Terre Haute Hottentots | Central League | , | |
| Joe Rickert | ricker001jos | 1904 | 4/23-9/25 | New Orleans Pelicans | Southern Association | , | |
| Branch Rickey | rickey001wes | 1904 | 6/23-8/15 | Dallas Giants | Texas League | , | |
| Dorsey Riddlemoser | riddle002dor | 1904 | Allentown | Pennsylvania State League | , | ||
| Jack Ridgway | ridgwa001jac | 1904 | Williamston | Independent | , | ||
| Arthur Riggs | riggs-002art | 1904 | 23 g. | Leavenworth Orioles | Missouri Valley League | , | |
| Charles Rigler | rigler001cy- | 1904-06 | Umpire | Central League | , | ||
| Riley | 1904 | 26 g. | Troy Trojans | New York State League | , | ||
| Riley | 1904 | Hudson Marines | Hudson River League | , | |||
| Riley | riley-051--- | 1904 | 4/29 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| James Riley | riley-010jam | 1904 | 8/12-9/2 | New Bedford Whalers | New England League | , | |
| William Riley | 1904 | 5/6-9/17 | Troy Trojans | New York State League | , | ||
| Frank Rinn | rinn--002fra | 1904 | 6/5- | Umpire | Tri-State League | , | |
| Frank Ripley | ripley001fra | 1904 | 5/7-9/5 | Burlington River Rats | Iowa League | , | |
| John? Rippin | rippin001--- | 1904 | 5/18-5/20 | Huntsville | Tennessee-Alabama League | , | |
| John? Rippin | rippin001--- | 1904 | Decatur | Tennessee-Alabama League | , | ||
| Pop Rising | rising001per | 1904 | 38 g. | New London Whalers | Connecticut State League | , | |
| Pop Rising | rising001per | 1904 | +6/16-8/13+ | Altoona Mountaineers | Tri-State League | , | |
| Dud Risley | risley001dud | 1904 | 119 g. | Iola Gasbags | Missouri Valley League | , | |
| William Ritchie | ritchi001wil | 1904 | Oxford PA | Independent | , | ||
| William Ritchie | ritchi001wil | 1904 | 9/17-9/29 | Williamsport Millionaires | Tri-State League | , | |
| Ritter | ritter010--- | 1904 | 25 g. | Joplin Miners | Missouri Valley League | , | |
| Ritter | ritter010--- | 1904 | Leavenworth Orioles | Missouri Valley League | , | ||
| Albert Ritter | ritter001alb | 1904 | Shawnee Browns/Chickasha Indians | Southwestern League | , | ||
| Harvey Ritter | ritter002har | 1904 | Pottstown | Pennsylvania League | , | ||
| Riva | 1904 | 6/4-7/19 | Umpire | New England League | , | ||
| Roach | roach-011--- | 1904 | 22 g. | Canton | Delta League | , | |
| Roach | 1904 | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | |||
| John Roach | roach-003joh | 1904 | no g. | Evansville River Rats | Central League | , | |
| John Roach | roach-003joh | 1904 | 4/23-4/30 | Montgomery Senators | Southern Association | , | |
| John Roach | roach-003joh | 1904 | 7/1-9/8 | Corning White Ponies | Southern Tier League | , | |
| Mike Roach | roach-001mik | 1904 | 5/6-9/18 | Ilion Typewriters | New York State League | , | |
| Skel Roach | roach-001rud | 1904 | 29 g. | Portland Browns | Pacific Coast League | , | |
| Frederick Robarge | robarg001fre | 1904 | Monson CT | Independent | , | ||
| Clay Robb | robb--001cla | 1904 | 5/2-8/29 | Beaumont Millionaires | South Texas League | , | |
| Clay Robb | robb--001cla | 1904 | postseason | Houston Wanderers | South Texas League | , | |
| Vince Robbins | robbin001vin | 1904 | +7/3+ | FW-Shamrocks | Independent | , | |
| Robenault | 1904 | 2 g. | Findlay OH | Independent | , | ||
| E. L. Roberts | 1904 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |||
| Harry Roberts | robert003har | 1904 | +6/1-7/2+ | Decatur | Tennessee-Alabama League | , | |
| Harry Roberts | robert003har | 1904 | 7/18- | Macon Highlanders | South Atlantic League | , | |
| John Robertshaw | robert014joh | 1904 | 12 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| Robertson | 1904 | 4/30-5/12 | Grand Rapids Orphans | Central League | , | ||
| Robertson | 1904 | 26 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | ||
| William Robertson | robert009wil | 1904 | Piqua OH | Independent | , | ||
| William Robertson | robert009wil | 1904 | 5/1,7/28-9/12 | Wheeling Stogies | Central League | , | |
| Robinson | robins070--- | 1904 | 5/20-5/22 | Roseburg Shamrocks | Oregon State League | , | |
| Bob Robinson | 1904 | Topeka-? | City League | , | |||
| Bob Robinson | 1904 | Topeka Saints | Missouri Valley League | , | |||
| Jack Robinson | robins006joh | 1904 | 86 g. | Jacksonville Jays | South Atlantic League | , | |
| Joshua Robinson | robins005jos | 1904 | 30 g. | Norwich Reds | Connecticut State League | , | |
| Rabbit Robinson | robins003wil | 1904 | Detroit | American League | Detroit, MI | ||
| Wilbert Robinson | robins001wil | 1904 | 4/29-7/2 | Baltimore Orioles | Eastern League | , | |
| Robishaw | 1904 | Yazoo City Zoos | Delta League | , | |||
| Chick Robitaille | robita001jos | 1904 | 5/7-8/30 | Troy Trojans | New York State League | , | |
| Chick Robitaille | robita001jos | 1904 | 9/2- | 9 g. | Pittsburgh | National League | Pittsburgh, PA |
| Mike Rochford | rochfo001mic | 1904 | Hartford Senators | Connecticut State League | , | ||
| Rochon | rochon000wal | 1904 | +6/26+ | Aberdeen Pippins | Southwest Washington League | , | |
| Rochon | 1904 | +7/4+ | Seattle Siwashes | Pacific Coast League | , | ||
| Walter Rochon | rochon000wal | 1904 | 5/8-8/7 | Aberdeen Pippins | Southwest Washington League | , | |
| Roy Rock | rock--002roy | 1904 | 4/30-9/28 | Providence Grays | Eastern League | , | |
| Ike Rockenfield | rocken001isa | 1904 | 17 g. | Portland Browns | Pacific Coast League | , | |
| Ike Rockenfield | rocken001isa | 1904 | 124 g. | Spokane Indians | Pacific National League | , | |
| Rogers | rogers030--- | 1904 | 5 g. | Leavenworth Orioles | Missouri Valley League | , | |
| Emmett Rogers | rogers002emm | 1904 | 5/1-5/23+ | Oklahoma City Mets | Southwestern League | , | |
| Emmett Rogers | rogers002emm | 1904 | Guthrie Blues | Southwestern League | , | ||
| Emmett Rogers | rogers002emm | 1904 | postseason | Coffeeville KS | Independent | , | |
| Fred Rogers | rogers002fra | 1904 | 5/19- | 58 g. | Superior Longshoremen | Northern League | , |
| Fred Rogers | rogers002fra | 1904 | +8/16+ | Portage Lake | Copper Country League | , | |
| James Rogers | rogers004jam | 1904 | +5/18-9/5 | Dollar Bay | Copper Country League | , | |
| Terry Rogers | rogers001ter | 1904 | 97 g. | New Haven Blues | Connecticut State League | , | |
| Terry Rogers | rogers001ter | 1904 | Norwich Reds | Connecticut State League | , | ||
| William Rogers | rogers001wil | 1904 | +7/15+ | Meriden Silverites | Connecticut State League | , | |
| William Rogers | rogers003wil | 1904 | 6/3-6/8 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |
| William Rogers | rogers003wil | 1904 | 6/10-8/7 | Columbia | Tennessee-Alabama League | , | |
| William Rogers | rogers003wil | 1904-07 | Quachita Baptist | College | , | ||
| George Rohe | rohe--001geo | 1904 | 4/23-9/25 | New Orleans Pelicans | Southern Association | , | |
| Dick Rohn | rohn--001ric | 1904 | 114 g. | Sedalia Goldbugs | Missouri Valley League | , | |
| William Roland | roland001wil | 1904 | 5/8-5/29 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| William Roland | roland001wil | 1904 | 5/30-6/27 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| William Roland | roland001wil | 1904 | 6/28-8/12 | Evansville River Rats | Central League | , | |
| Dillwyn Rollins | rollin001j-- | 1904 | Dartmouth Col. | College | , | ||
| Dillwyn Rollins | rollin001j-- | 1904 | 6/20-9/17 | Nashua | New England League | , | |
| Pat Rollins | rollin001hen | 1904 | Oxford | Pennsylvania League | , | ||
| Romer | 1904 | 4.29-5/30 | Roseburg Shamrocks | Oregon State League | , | ||
| Romer | 1904 | Gold Hill | Rogue River Valley | , | |||
| E. N. Romig | romig-000en- | 1904 | Davenport River Rats | Illinois-Indiana-Iowa League | , | ||
| E. N. Romig | romig-000en- | 1904 | 9/21-9/25 | St. Joseph Saints | Western League | , | |
| John Root | root--001joh | 1904 | 49 g. | Iola Gasbags | Missouri Valley League | , | |
| Charles Rose | rose--004cha | 1904 | 5/19- | 66 g. | Fargo | Northern League | , |
| Charles Rose | rose--004cha | 1904 | +8/23+ | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Ross | 1904 | 18 g. | Canton OH | Independent | , | ||
| Ross | 1904 | 9/17 | Utica Pent-Ups | New York State League | , | ||
| Ross | ross--024--- | 1904 | Monroe Hill Citys | Cotton States League | , | ||
| Ross | ross--002ber | 1904 | +7/15-8/26+ | Cripple Creek CO | Independent | , | |
| Ross | ross--002ber | 1904 | 8/30 | Colorado Springs Millionaires | Western League | , | |
| Art Ross | ross--001art | 1904 | Lodi | California State League | , | ||
| Art Ross | ross--001art | 1904 | 196 g. | Los Angeles Angels | Pacific Coast League | , | |
| Bert Ross | ross--002ber | 1904 | +7/15-8/26+ | Cripple Creek CO | Independent | , | |
| Bert Ross | ross--002ber | 1904 | 8/30 | Colorado Springs Millionaires | Western League | , | |
| D. Ross | ross--002d-- | 1904 | 4/24-5/19 | Shreveport Pirates | Southern Association | , | |
| Ernie Ross | ross--001ern | 1904 | Norwich Reds | Connecticut State League | , | ||
| Claude Rossman | rossma001cla | 1904 | 82 g. | Holyoke Paperweights | Connecticut State League | , | |
| Claude Rossman | rossma001cla | 1904 | 9/16- | 18 g. | Cleveland | American League | Cleveland, OH |
| Lester Rosson | rosson001les | 1904 | 4/28-5/26 | Nashville Volunteers | Southern Association | , | |
| Lester Rosson | rosson001les | 1904 | 45 g. | Charleston Sea Gulls | South Atlantic League | , | |
| Andy Roth | roth--001and | 1904 | 110 g. | Augusta Tourists | South Atlantic League | , | |
| Andy Roth | roth--001and | 1904 | Savannah Pathfinders | South Atlantic League | , | ||
| Bill Roth | roth--001wil | 1904 | +5/18-6/16+ | Dollar Bay | Copper Country League | , | |
| Frank Roth | roth--001fra | 1904 | 81 g. | Philadelphia | National League | Philadelphia, PA | |
| Bobby Rothermel | rother001bob | 1904 | 311 ab | Greenville Cotton Pickers | Cotton States League | , | |
| George Rothermel | rother000geo | 1904 | Garwin IA | Independent | , | ||
| Jack Rothfuss | rothfu001jac | 1904 | Independent | , | |||
| Jack Rothfuss | rothfu001jac | 1904 | 6/17-9/5 | Kansas City Blues | American Association | , | |
| Claude Rothgeb | rothge001cla | 1904-05 | Univ. Illinois | College | , | ||
| Billy Rourke | rourke001wil | 1904 | 4/24-9/25 | Omaha Rangers | Western League | , | |
| Dave Rowan | rowan-001dav | 1904 | no g. | Syracuse Stars | New York State League | , | |
| Rowe | rowe--015--- | 1904 | 4/4- | Davidson College | College | , | |
| Royer | royer-003--- | 1904-05 | Univ. of Kansas | College | , | ||
| W. F. Royers | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |||
| Ted Ruark | 1904 | 5/13-6/15 | Waterloo Microbes | Iowa League | , | ||
| Jesse Ruby | ruby--001jes | 1904 | 116 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Nap Rucker | rucker001geo | 1904 | 9/2-9/23 | Atlanta Crackers | Southern Association | , | |
| Orlando Rudd | rudd--001o-- | 1904 | 5/6-7/6 | Oskaloosa Quakers | Iowa League | , | |
| Orlando Rudd | rudd--001o-- | 1904 | 7/7-9/5 | Waterloo Microbes | Iowa League | , | |
| Frank Rudderham | rudder001fra | 1904 | 6/5-6/18 | Albany Senators | New York State League | , | |
| Frank Rudderham | rudder001fra | 1904 | 6/25-7/20 | Troy Trojans | New York State League | , | |
| John Rudderham | rudder001joh | 1904 | 4/30-9/17 | Umpire | New England League | , | |
| Dick Rudolph | rudolp001ric | 1904 | Morris HS | High School | , | ||
| Dick Rudolph | rudolp001ric | 1904 | 9/10 | Providence Grays | Eastern League | , | |
| John Rudolph | rudolp001joh | 1904 | Sharon PA | Independent | , | ||
| John Rudolph | rudolp001joh | 1904 | - 7/17 | 2 g. | Chicago | National League | Chicago, IL |
| John Rudolph | rudolp001joh | 1904 | 8/4-8/13 | Utica Pent-Ups | New York State League | , | |
| C. Ruening | ruenin001c-- | 1904 | 7/29-9/12 | Troy Trojans | New York State League | , | |
| Paul Ruff | ruff--001pau | 1904 | 5/8-9/5+ | Centralia Midgets | Southwest Washington League | , | |
| Harry Ruh | ruh---001har | 1904 | 404 ab | Baton Rouge Red Sticks | Cotton States League | , | |
| Gus Ruhland | ruhlan001gus | 1904 | 121 g. | Jacksonville Jays | South Atlantic League | , | |
| Louis Runkel | runkle001lou | 1904 | 50 g. | Portland Browns | Pacific Coast League | , | |
| Louis Runkel | runkle001lou | 1904 | 129 g. | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Clyde Rupert | rupert000red | 1904 | 4/29-5/1 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Clyde Rupert | rupert000red | 1904 | 6/2-6/23 | Roseburg Shamrocks | Oregon State League | , | |
| Clyde Rupert | rupert000red | 1904 | +7/1-7/4 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Russell | 1904 | Dallas Giants | Texas League | , | |||
| Clyde Russell | russel001cly | 1904 | 4/22-9/24 | Nashville Volunteers | Southern Association | , | |
| Cy Russell | russel002fra | 1904 | San Jose | California State League | , | ||
| Frank Russell | 1904 | Toledo Mud Hens | American Association | , | |||
| H. L. Russell | russel000roy | 1904 | 5/8-9/4 | Centralia Midgets | Southwest Washington League | , | |
| J. J. Russell | 1904 | Pine Bluff Lumbermen | Cotton States League | , | |||
| John Russell | russel006jac | 1904 | 5/3-7/18 | Wilmington Peaches | Tri-State League | , | |
| John Russell | russel006jac | 1904 | 9/10-9/27 | York Penn Parks | Tri-State League | , | |
| N. W. Russell | russel001n-- | 1904 | 50 g. | Clarksdale | Delta League | , | |
| Austin Rutherford | ruther001aus | 1904 | 6/29-9/9 | Addison White Sox | Southern Tier League | , | |
| Joseph Rutherford | ruther001jos | 1904 | Baltimore Orioles | Eastern League | , | ||
| Lou Rutledge | rutled001lou | 1904 | 48+ g. | Cairo Champions | Kentucky-Illinois-Tennessee League | , | |
| Ryan | ryan--006wil | 1904 | 9/17 | Syracuse Stars | New York State League | , | |
| Ryan | ryan--037--- | 1904 | 67 g. | Youngstown OH | Independent | , | |
| Ryan | ryan--037--- | 1904 | +7/8-9/20 | Sharon PA | Independent | , | |
| Ryan | ryan--037--- | 1904 | San Francisco | California State League | , | ||
| Jack Ryan | ryan--004joh | 1904 | 4/20-9/18 | Kansas City Blues | American Association | , | |
| Jack Ryan | ryan--001jac | 1904 | 24 g. | Jackson Senators | Delta League | , | |
| Jimmy Ryan | ryan--003jam | 1904 | 4/24-9/25 | Colorado Springs Millionaires | Western League | , | |
| Joseph Ryan | ryan--001jos | 1904 | 9/2 | Haverhill Hustlers | New England League | , | |
| Paul Ryan | ryan--003pau | 1904 | 24 g. | Jackson Senators | Delta League | , | |
| Raymond Ryan | ryan--001ray | 1904 | Sydney OH | Independent | , | ||
| William Ryan | ryan--006wil | 1904 | 5/6-5/17 | Troy Trojans | New York State League | , | |
| William Ryan | ryan--006wil | 1904 | 5/31-7/10 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| William Ryan | ryan--006wil | 1904 | 7/16-7/17 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Edwin Sabrie | sabrie001edw | 1904 | Vicksburg Hill Billies | Cotton States League | , | ||
| James Sager | sager-001jam | 1904 | 4/28-9/11 | South Bend Greens | Central League | , | |
| Harry Saillard | sailla001har | 1904 | 5/16-7/6+ | Huntsville | Tennessee-Alabama League | , | |
| Harry Saillard | sailla001har | 1904 | 54 g. | Jackson Senators | Delta League | , | |
| John Saladin | saladi002joh | 1904 | 7/17 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Solly Salisbury | salisb001wil | 1904 | no g. | Minneapolis Millers | American Association | , | |
| Walter Salm | salm--001wal | 1904 | 4/27-8/15 | Corsicana Oil Citys | Texas League | , | |
| Guy Sample | sample001guy | 1904 | 3/31 | Tacoma Tigers | Pacific Coast League | , | |
| Guy Sample | sample001guy | 1904 | 4/26-5/27 | St. Joseph Saints | Western League | , | |
| Guy Sample | sample001guy | 1904 | 325 ab | Pine Bluff Lumbermen | Cotton States League | , | |
| Sanders | sander027--- | 1904 | +5/24-5/25+ | Columbia | Tennessee-Alabama League | , | |
| Reuben Sanders | sander000rub | 1904 | 6/17 | Eugene Blues | Oregon State League | , | |
| Reuben Sanders | sander000rub | 1904-07 | Sherman Institute | School | , | ||
| War Sanders | sander001war | 1904 | - 7/4 | 4 g. | St. Louis | National League | St. Louis, MO |
| War Sanders | sander001war | 1904 | 7/22-9/23 | Omaha Rangers | Western League | , | |
| Nelson Sandherr | sandhe001nel | 1904 | Chester PA | Independent | , | ||
| Nelson Sandherr | sandhe001nel | 1904 | Williamsport PA | Independent | , | ||
| Nelson Sandherr | sandhe001nel | 1904 | +6/23+ | Johnstown PA | Independent | , | |
| William Sanford | sanfor000wil | 1904 | 27 g. | Augusta Tourists | South Atlantic League | , | |
| William Sanford | sanfor000wil | 1904 | +6/27-8/2+ | Decatur | Tennessee-Alabama League | , | |
| Sapp | sapp--001--- | 1904 | Johnstown PA | Independent | , | ||
| Charles Sapp | sapp--002cha | 1904 | 4/30-5/1 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Charles Sapp | sapp--002--- | 1904 | 5/11-5/12 | Grand Rapids Orphans | Central League | , | |
| Charles Sapp | sapp--007--- | 1904 | 5/24-5/25 | Dayton Veterans | Central League | , | |
| Charles Sapp | sapp--002cha | 1904 | 6/2-6/19 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Sappe | 1904 | 6 g. | Niles OH | Independent | , | ||
| Sarry | sarry-001--- | 1904 | 1 g. | Huntsville | Tennessee-Alabama League | , | |
| Waldo Sasse | sasse-003--- | 1904 | 81 g. | Warren OH | Independent | , | |
| Howard Savage | savage000how | 1904 | Univ. Wisconsin | College | , | ||
| Howard Savage | savage000how | 1904 | Aurora IL | Independent | , | ||
| Howard Savage | savage000how | 1904 | 5/20-6/28 | Colorado Springs Millionaires | Western League | , | |
| Howard Savage | savage000how | 1904 | 7/6-7/19 | Boone Coal Miners | Iowa League | , | |
| Ralph Savidge | savidg001ral | 1904 | 46 g. | Savannah Pathfinders | South Atlantic League | , | |
| Ralph Savidge | savidg001ral | 1904 | 9/21-9/30 | Williamsport Millionaires | Tri-State League | , | |
| Sheep Sawyer | sawyer010--- | 1904 | 5/16-6/15 | Huntsville | Tennessee-Alabama League | , | |
| Sheep Sawyer | sawyer010--- | 1904 | 6/16-6/20+ | Bessemer | Tennessee-Alabama League | , | |
| Sheep Sawyer | sawyer010--- | 1904 | +6/27-8/3+ | Sheffield | Tennessee-Alabama League | , | |
| Ed Scala | 1904 | Galveston Sand Crabs | South Texas League | , | |||
| Doc Scanlan | scanla001wil | 1904 | 4 g. | Pittsburgh | National League | Pittsburgh, PA | |
| Doc Scanlan | scanla001wil | 1904 | Plattsburgh | Northern New York League | , | ||
| Doc Scanlan | scanla001wil | 1904 | 13 g. | Brooklyn | National League | Brooklyn, NY | |
| Scanlon | 1904 | 11 g. | Findlay OH | Independent | , | ||
| Robert Scanlon | scanlo001rob | 1904 | Kingston Colonials | Hudson River League | , | ||
| Lindsay Scarbrough | scarbr002--- | 1904 | 1 g. | Anniston | Tennessee-Alabama League | , | |
| Edward Schaaf | schaaf001ed- | 1904 | 10 g. | Fort Scott Giants | Missouri Valley League | , | |
| Schaefer | schaef017--- | 1904 | Jackson Senators | Delta League | , | ||
| Ben Schaefer | 1904 | Evansville River Rats | Central League | , | |||
| George Schaefer | schaef002geo | 1904 | 5/1-9/11 | South Bend Greens | Central League | , | |
| Germany Schaefer | schaef001her | 1904 | Milwaukee Brewers | American Association | , | ||
| Ed Schaeffer | 1904 | 93 g. | Boone Coal Miners | Iowa League | , | ||
| Ed Schaeffer | 1904 | Waterloo Microbes | Iowa League | , | |||
| Ed Schaeffer | 1904 | Burlington River Rats | Iowa League | , | |||
| Schafer | schafe008--- | 1904 | +5/30+ | Big Duluth | Independent | , | |
| Schafer | schafe008--- | 1904 | 8/6-8/13 | Duluth White Sox | Northern League | , | |
| Schafer | schafe008--- | 1904 | -9/25 | Big Duluth | Independent | , | |
| Ben Schafstall | schafs001ber | 1904 | 4/25-5/7 | Omaha Rangers | Western League | , | |
| Ben Schafstall | schafs001ber | 1904 | 6/21-6/25 | Omaha Rangers | Western League | , | |
| Ben Schafstall | schafs001ber | 1904 | Grand Island NB | Independent | , | ||
| Henry Scharnweber | scharn001hen | 1904 | 5/19-7/24 | Grand Forks Forkers | Northern League | , | |
| Henry Scharnweber | scharn001hen | 1904 | +8/4-9/5 | Waterloo Microbes | Iowa League | , | |
| Fred Schatzke | schatz001fre | 1904 | St. Edwards Col. | College | , | ||
| Fred Schatzke | schatz001fre | 1904 | 4/30-9/2 | Galveston Sand Crabs | South Texas League | , | |
| Schaub | schaub005--- | 1904 | 9/16 | Rochester Bronchos | Eastern League | , | |
| Bob Schaub | schaub001rob | 1904 | 4/23-9/24 | Shreveport Pirates | Southern Association | , | |
| Frank Schaub | schaub001fra | 1904 | 5/7-8/4+ | Waterloo Microbes | Iowa League | , | |
| Frank Schaub | schaub001fra | 1904 | -9/5 | Fort Dodge Gypsum Eaters | Iowa League | , | |
| Louis Schaub | schaub001lou | 1904 | 5/7-9/5 | Ottumwa Standpatters | Iowa League | , | |
| Ted Scheffler | scheff001ted | 1904 | 7/14-7/16 | Manchester | New England League | , | |
| Frank Scheibeck | scheib001fra | 1904 | 4/30-9/24 | St. Joseph Saints | Western League | , | |
| Louis Schettler | schett001lou | 1904 | Natchez Indians | Cotton States League | , | ||
| Louis Schettler | schett001lou | 1904 | 15 g. | Brookhaven | Delta League | , | |
| Lou Schiappacasse | schiap001lou | 1904 | 424 ab | Monroe Hill Citys | Cotton States League | , | |
| Bert Schils | schils001alb | 1904 | 44 g. | Crookston Crooks | Northern League | , | |
| Bert Schils | schils001alb | 1904 | 7/30-9/25 | Des Moines Prohibitionists | Western League | , | |
| Schilsky | schils002--- | 1904 | 6/18-6/22 | Lebanon | Tri-State League | , | |
| Larry Schlafly | schlaf001har | 1904 | 198 g. | Oakland Oaks | Pacific Coast League | , | |
| Admiral Schlei | schlei001geo | 1904 | Cincinnati | National League | Cincinnati, OH | ||
| Schleier | schlei003--- | 1904 | 9/3 | Des Moines Prohibitionists | Western League | , | |
| Claude Schmeer | schmee001cla | 1904 | Portland Browns | Pacific Coast League | , | ||
| Claude Schmeer | schmee001cla | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| Schmidt | schmid005--- | 1904 | +5/23-8/10+ | Columbia | Tennessee-Alabama League | , | |
| Boss Schmidt | schmid001cha | 1904 | 107 g. | Springfield Midgets | Missouri Valley League | , | |
| Boss Schmidt | schmid001cha | 1904 | 9/16-9/20 | Minneapolis Millers | American Association | , | |
| Henry Schmidt | schmid004hen | 1904 | 70 g. | Oakland Oaks | Pacific Coast League | , | |
| Crazy Schmit | schmit001fre | 1904 | 36 g. | Yazoo City Zoos | Delta League | , | |
| August Schnack | 1904 | Hudson Marines | Hudson River League | , | |||
| Frank Schneiberg | schnei001fra | 1904 | Rockford Red Sox | Illinois-Indiana-Iowa League | , | ||
| Frank Schneiberg | schnei001fra | 1904 | 17 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Fred Schock | schock001fre | 1904 | 5 g. | Seattle Siwashes | Pacific Coast League | , | |
| Emmett Schofield | schofi001emm | 1904 | 4/28-7/4 | Eugene Blues | Oregon State League | , | |
| Frank Scholler | schoel001fra | 1904 | 5/17-5/29 | Evansville River Rats | Central League | , | |
| Walter Schooler | school001wal | 1904 | preseason | Waterloo Microbes | Iowa League | , | |
| Thomas Schoonhoven | schoon001tho | 1904 | 4/- | 64 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , |
| Thomas Schoonhoven | schoon001tho | 1904 | 6/16-7/ | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| Thomas Schoonhoven | schoon001tho | 1904 | +7/24-7/27+ | Oskaloosa Quakers | Iowa League | , | |
| Grant Schopp | schopp001gra | 1904 | 5/6-9/5 | Ottumwa Standpatters | Iowa League | , | |
| Grant Schopp | schopp001gra | 1904 | +9/13 | North English IA | Independent | , | |
| W. Schott | schott001w-- | 1904 | Canton | Delta League | , | ||
| Joe Schrall | schral001jos | 1904 | 5/6-9/18 | Albany Senators | New York State League | , | |
| John Schrant | schran001joh | 1904 | 121 g. | Sedalia Goldbugs | Missouri Valley League | , | |
| John Schrant | schran001joh | 1904 | Topeka Saints | Missouri Valley League | , | ||
| John Schrant | schran001joh | 1904 | 9/20 | Kansas City Blues | American Association | , | |
| Ossee Schrecongost | schrec001oss | 1904 | Philadelphia | American League | Philadelphia, PA | ||
| Frank Schreiner | schrin001f-- | 1904 | +6/19-8/14+ | Kaukauna WI | Independent | , | |
| Pop Schriver | schriv001wil | 1904 | 4/20-9/19 | Louisville Colonels | American Association | , | |
| Schroeder | schroe015--- | 1904 | 7/1-8/4 | Hornellsville Maple Cities | Southern Tier League | , | |
| Schroeder | schroe015--- | 1904 | 8/9-8/12 | Penn Yan Grape Pickers | Southern Tier League | , | |
| Cap Schroeder | schroe001cas | 1904 | 35 g. | Hattiesburg | Delta League | , | |
| Mike Schroeder | schroe000mik | 1904 | 8/30-9/10 | Fall River Indians | New England League | , | |
| Tony Schubert | schube000ton | 1904 | +8/26+ | Lake Linden Lakers | Copper Country League | , | |
| Schudt | schudt000--- | 1904 | 9/15-9/17 | Troy Trojans | New York State League | , | |
| Frank Schulte | schult001fra | 1904 | 5/6-9/18 | Syracuse Stars | New York State League | , | |
| Frank Schulte | schult001fra | 1904 | 9/21- | 20 g. | Chicago | National League | Chicago, IL |
| Jack Schulte | schult003joh | 1904 | 5/6-6/24 | Syracuse Stars | New York State League | , | |
| Jack Schulte | schult003joh | 1904 | Plattsburgh | Northern New York League | , | ||
| Schultz | schult011--- | 1904 | Chester | Pennsylvania League | , | ||
| C. O. Schultz | 1904 | Umpire | Central League | , | |||
| George Schultz | schult001geo | 1904 | 4/29-9/22 | Rochester Bronchos | Eastern League | , | |
| Ernst Schulz | schulz001ern | 1904 | no g. | Greenville Cotton Pickers | Cotton States League | , | |
| Ernst Schulz | schulz001ern | 1904 | 92 g. | Canton | Delta League | , | |
| Hack Schumann | schuma002car | 1904 | no g. | Ilion Typewriters | New York State League | , | |
| Hack Schumann | schuma002car | 1904 | 5/8-6/3 | Utica Pent-Ups | New York State League | , | |
| Jack Schuster | schust001--- | 1904 | Umpire | Kentucky-Illinois-Tennessee League | , | ||
| Jack Schuster | schust001--- | 1904 | +8/8-8/9+ | Boone Coal Miners | Iowa League | , | |
| Jack Schuster | schust001--- | 1904 | 9/8-9/17 | Umpire | American Association | , | |
| Joseph Schwab | schwab001jos | 1904 | 41+ g. | Cairo Champions | Kentucky-Illinois-Tennessee League | , | |
| Joseph Schwab | schwab001jos | 1904 | 10 g. | Canton | Delta League | , | |
| Bill Schwartz | schwar003wil | 1904 | 5/2-6/16 | Cleveland | American League | Cleveland, OH | |
| Bill Schwartz | schwar003wil | 1904 | 53 g. | Akron OH | Independent | , | |
| Charles Schwartz | schwar001cha | 1904 | 4/21-9/25 | Montgomery Senators | Southern Association | , | |
| Edward Schwartz | schwar003edw | 1904 | 6/5-9/4 | Hoquiam Perfect Gentlemen | Southwest Washington League | , | |
| Rudy Schwenck | schwen001rud | 1904 | Vicksburg Hill Billies | Cotton States League | , | ||
| Arlo Scoggins | scoggi001arl | 1904 | Iola St. College | College | , | ||
| Arlo Scoggins | scoggi001arl | 1904 | 113 g. | Iola Gasbags | Missouri Valley League | , | |
| Scott | 1904 | 43 g. | Newark OH | Independent | , | ||
| Dick Scott | scott-001amo | 1904 | 4/23 | Columbus Senators | American Association | , | |
| Dick Scott | scott-001amo | 1904 | 4/29-9/1 | Terre Haute Hottentots | Central League | , | |
| George Scott | scott-004geo | 1904 | 5/7-8/28 | Binghamton Bingoes | New York State League | , | |
| George Scott | scott-004geo | 1904 | 9/4-9/18 | Louisville Colonels | American Association | , | |
| Joseph Scott | scott-004jos | 1904 | Davenport River Rats | Illinois-Indiana-Iowa League | , | ||
| Trammel Scott | 1904-05 | Univ. of Georgia | College | , | |||
| William Scudder | scudde002--- | 1904 | 6/16-6/22 | Altoona Mountaineers | Tri-State League | , | |
| William Scudder | scudde001wil | 1904 | 7/8-8/19 | Wellsville Oil Drillers | Southern Tier League | , | |
| William Scudder | scudde001wil | 1904 | 8/23-8/30 | Addison White Sox | Southern Tier League | , | |
| William Scudder | scudde001wil | 1904 | 9/10 | Coatesville | Pennsylvania League | , | |
| P. C. Scullin | 1904 | 5/11-9/14 | Cairo Champions | Kentucky-Illinois-Tennessee League | , | ||
| James Seabough | seabou001jam | 1904 | 94 g. | Pittsburg Coal Diggers | Missouri Valley League | , | |
| Jimmy Seagraves | seagra001cha | 1904 | Carlisle | Pennsylvania League | , | ||
| Jimmy Seagraves | seagra001cha | 1904 | Mt. Carmel AA | Independent | , | ||
| Jimmy Seagraves | seagra001cha | 1904 | +9/27-9/30 | Lebanon | Tri-State League | , | |
| Frank Sealts | 1904 | -6/16 | 16 g. | Warren OH | Independent | , | |
| Frank Sealts | 1904 | +8/6+ | Lima OH | Independent | , | ||
| Seaman | 1904 | 49 g. | Mansfield OH | Independent | , | ||
| Seaman | 1904 | Newark OH | Independent | , | |||
| Walter Seare | seare-000wal | 1904 | 8/19- | Salt Lake City Elders | Pacific National League | , | |
| Harry Seay | seay--001h-- | 1904 | 4/30-8/2 | Beaumont Millionaires | South Texas League | , | |
| Harry Seay | seay--001h-- | 1904 | 8/17-8/31 | Galveston Sand Crabs | South Texas League | , | |
| Jimmy Sebring | sebrin001jam | 1904 | 80 g. | Pittsburgh | National League | Pittsburgh, PA | |
| Jimmy Sebring | sebrin001jam | 1904 | 56 g. | Cincinnati | National League | Cincinnati, OH | |
| Charles Sechrist | sechri001cha | 1904 | 4/30- | Fall River Indians | New England League | , | |
| Charles Sechrist | sechri001cha | 1904 | -9/17 | Haverhill Hustlers | New England League | , | |
| Doc Sechrist | sechri001doc | 1904 | 10 g. | Savannah Pathfinders | South Atlantic League | , | |
| Doc Sechrist | sechri001doc | 1904 | Waycross GA | Independent | , | ||
| Doc Sechrist | sechri001doc | 1904 | Augusta Tourists | South Atlantic League | , | ||
| Otis Sedgwick | sedgwi001oti | 1904 | U. Vermont | College | , | ||
| William Sedgwick | sedgwi001wil | 1904 | -7/31 | North English IA | Independent | , | |
| William Sedgwick | sedgwi001wil | 1904 | 8/3-9/5 | Boone Coal Miners | Iowa League | , | |
| Seely | 1904 | 5/18 | Chattanooga | Tennessee-Alabama League | , | ||
| H. Seewald | sewald001har | 1904 | Portsmouth OH | Independent | , | ||
| John Segars | segars001joh | 1904 | 11 g. | Macon Highlanders | South Atlantic League | , | |
| John Seibert | seiber002joh | 1904 | 8/17-9/9 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| John Seibert | seiber002joh | 1904 | 17 g. | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Sammy Seifert | 1904 | Sharon OH | Independent | , | |||
| Sammy Seifert | 1904 | 8/9 | Ashtabula OH | Independent | , | ||
| George Seigle | seigle001geo | 1904 | 122 g. | Iola Gasbags | Missouri Valley League | , | |
| Edward Seitz | seitz-001edw | 1904 | 5/10-5/20 | Decatur | Tennessee-Alabama League | , | |
| Edward Seitz | seitz-001edw | 1904 | 6/3-6/5 | Burlington River Rats | Iowa League | , | |
| Joseph Seitz | seitz-000joe | 1904 | Georgetown Col | College | , | ||
| Joseph Seitz | seitz-000joe | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| Joseph Seitz | seitz-000joe | 1904 | 8/18-9/10 | Elmira | Southern Tier League | , | |
| Kip Selbach | selbac001alb | 1904 | 48 g. | Washington | American League | Washington, DC | |
| Kip Selbach | selbac001alb | 1904 | 98 g. | Boston | American League | Boston, MA | |
| Al Selby | selby-001alb | 1904 | 4/28-7/25 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Al Selby | selby-001alb | 1904 | So McAlester | , | |||
| Reed Self | self--004--- | 1904 | +7/24+ | Dall.-Sanger Bros. | Independent | , | |
| G. W. Selig | selig-000gw- | 1904 | 4/28-5/3 | Fort Wayne Railroaders | Central League | , | |
| Selley | 1904 | Clarksville TN | Independent | , | |||
| Selley | 1904 | 1 g. | Sheffield | Tennessee-Alabama League | , | ||
| Joseph Senior | 1904 | Chester PA | Independent | , | |||
| John Sens | sens--001joh | 1904 | 24 g. | Macon Highlanders | South Atlantic League | , | |
| John Sens | sens--001joh | 1904 | Columbia Skyscrapers | South Atlantic League | , | ||
| John Sens | sens--001joh | 1904 | 60 g. | Hattiesburg | Delta League | , | |
| Paul Sentell | sentel001leo | 1904 | 108 g. | Macon Highlanders | South Atlantic League | , | |
| Bert Senter | senter001--- | 1904 | Topeka Saints | Missouri Valley League | , | ||
| Albert Servatius | servat001alb | 1904 | +7/13-8/14+ | Austin PA | Independent | , | |
| Perry Sessions | sessio001per | 1904 | 4/22-9/20 | St. Paul Saints | American Association | , | |
| William Setley | setley001wil | 1904 | Umpire | Kentucky-Illinois-Tennessee League | , | ||
| Al Severoid | 1904 | 8/2-8/7 | Grand Forks Forkers | Northern League | , | ||
| Harry Sewald | sewald001har | 1904 | 17 g. | Piqua OH | Independent | , | |
| Frank Sexton | sexton001fra | 1904-06 | Brown Univ. | College | , | ||
| Thomas Seymour | seymou000tho | 1904 | no g. | Des Moines Prohibitionists | Western League | , | |
| Joe Shackleton | shackl001jos | 1904 | Hoboken NJ | Independent | , | ||
| Ed. Shafer | schaef001e-- | 1904 | 5/7-6/3 | Boone Coal Miners | Iowa League | , | |
| Ed. Shafer | schaef001e-- | 1904 | 6/7-7/27+ | Waterloo Microbes | Iowa League | , | |
| Ed. Shafer | schaef001e-- | 1904 | +8/1-9/5 | Burlington River Rats | Iowa League | , | |
| Ed. Shafer | schaef001e-- | 1904 | 93 g. | Boone Coal Miners | Iowa League | , | |
| Ed. Shafer | schaef001e-- | 1904 | Waterloo Microbes | Iowa League | , | ||
| Ed. Shafer | schaef001e-- | 1904 | Burlington River Rats | Iowa League | , | ||
| Charlie Shaffer | shaffe001cha | 1904 | Butte Miners/Fruit Pickers | Pacific National League | , | ||
| Charlie Shaffer | shaffe001cha | 1904 | Spokane Indians | Pacific National League | , | ||
| Theodore Shaffer | shaffe001the | 1904 | 13 ab | Pine Bluff Lumbermen | Cotton States League | , | |
| Shanabrook | shanna001war | 1904 | Massillon OH | Independent | , | ||
| Bert Shaner | shaner001ber | 1904 | Herington | Central Kansas State League | , | ||
| Bert Shaner | shaner001ber | 1904 | +9/27+ | Emporia KS | Independent | , | |
| Luther Shanks | shanks001lut | 1904 | Umpire | Missouri Valley League | , | ||
| Shannon | 1904 | Cairo Champions | Kentucky-Illinois-Tennessee League | , | |||
| Frank Shannon | shanno002fra | 1904 | Bowdoin College | College | , | ||
| Owen Shannon | shanno001owe | 1904 | 5/14-5/29 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Owen Shannon | shanno001owe | 1904 | 5/30-7/30 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Owen Shannon | shanno001owe | 1904 | 7/31-9/1 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Spike Shannon | shanno003wil | 1904 | 134 g. | St. Louis | National League | St. Louis, MO | |
| Peck Sharp | sharp-001jim | 1904 | 4/26-6/5 | Umpire | Pacific National League | , | |
| Bud Sharpe | sharpe001bay | 1904 | WC-Brandywine | Independent | , | ||
| Jack Sharrott | sharro001jac | 1904 | Ilion Typewriters | New York State League | , | ||
| Shag Shaughnessy | shaugh001fra | 1904 | Southern Illinois | , | |||
| Shag Shaughnessy | shaugh001fra | 1904 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | ||
| August Shaumeyer | schaum001aug | 1904 | 119 g. | Iola Gasbags | Missouri Valley League | , | |
| Clinton Shaver | shaver001g-- | 1904 | Spartanburg SC | Independent | , | ||
| Al Shaw | shaw--001alf | 1904 | 5/4-8/12 | Buffalo Bisons | Eastern League | , | |
| Al Shaw | shaw--001alf | 1904 | 9/28 | Buffalo Bisons | Eastern League | , | |
| Frank Shaw | shaw--001fra | 1904 | 5/19-6/6 | Duluth White Sox | Northern League | , | |
| Frank Shaw | shaw--001fra | 1904 | 6/9-7/12+ | Superior Longshoremen | Northern League | , | |
| Frank Shaw | shaw--001fra | 1904 | +7/22-8/5 | Duluth White Sox | Northern League | , | |
| Hunky Shaw | shaw--001roy | 1904-06 | U. of Washington | College | , | ||
| Hunky Shaw | shaw--001roy | 1904 | 1 g. | Portland Browns | Pacific Coast League | , | |
| Hunky Shaw | shaw--001roy | 1904 | 5/26-7/4 | Roseburg Shamrocks | Oregon State League | , | |
| Hunky Shaw | shaw--001roy | 1904 | 7/10-7/24 | Centralia Midgets | Southwest Washington League | , | |
| John Shaw | shaw--007joh | 1904 | 5/6-9/18 | Ilion Typewriters | New York State League | , | |
| Danny Shay | shay--001dan | 1904 | Stockton | California State League | , | ||
| Danny Shay | shay--001dan | 1904 | St. Louis | National League | St. Louis, MO | ||
| Danny Shay | shay--001dan | 1904 | Portland Browns | Pacific Coast League | , | ||
| Shea | shea--036--- | 1904 | 9/5-9/10 | Elmira | Southern Tier League | , | |
| Danny Shea | shea--001dan | 1904 | Portland Browns | Pacific Coast League | , | ||
| Danny Shea | shea--001dan | 1904 | +7/22+ | San Francisco Seals | Pacific Coast League | , | |
| Danny Shea | shea--001dan | 1904 | Seattle Siwashes | Pacific Coast League | , | ||
| Danny Shea | shea--001dan | 1904 | +12/3+ | Stockton | California State League | , | |
| Dennie Shea | shea--001den | 1904 | 110 g. | Columbia Skyscrapers | South Atlantic League | , | |
| Nap Shea | shea--001joh | 1904 | 5/4-9/23 | Newark Sailors | Eastern League | , | |
| Sheehan | 1904 | 87 g. | Niles OH | Independent | , | ||
| Tommy Sheehan | sheeha003tho | 1904 | 216 g. | Tacoma Tigers | Pacific Coast League | , | |
| Roy Sheets | sheets001roy | 1904 | 4/30-9/17 | Concord Marines | New England League | , | |
| William Sheffield | sheffi001--- | 1904 | Oklahoma City Mets | Southwestern League | , | ||
| Ben Shelton | shelto001ben | 1904 | 4/27-6/29 | Corsicana Oil Citys | Texas League | , | |
| Ben Shelton | shelto001ben | 1904 | 7/4-9/2 | Galveston Sand Crabs | South Texas League | , | |
| George Sheppard | sheppa001geo | 1904 | 42 g. | Duluth White Sox | Northern League | , | |
| Jack Sheridan | sherid001jac | 1904 | MLB Umpire | American League | , | ||
| Sherman | 1904 | 5 g. | Kane PA | Independent | , | ||
| John Sherman | sherma004--- | 1904 | 32 g. | Paducah Indians | Kentucky-Illinois-Tennessee League | , | |
| John Sherman | sherma004--- | 1904 | +8/20+ | Evansville River Rats | Central League | , | |
| John Sherman | sherma004--- | 1904 | +9/3-9/11+ | Terre Haute Hottentots | Central League | , | |
| Ray Sherwood | sherwo001--- | 1904 | +8/1+ | Aberdeen Pippins | Southwest Washington League | , | |
| Simon Shetter | 1904 | Phil.-So.Athletic | Independent | , | |||
| Charlie Shields | shield002cha | 1904 | 53 g. | Portland Browns | Pacific Coast League | , | |
| Charlie Shields | shield002cha | 1904 | Seattle Siwashes | Pacific Coast League | , | ||
| Anton Shimonek | shimon001ant | 1904 | 125 g. | Joplin Miners | Missouri Valley League | , | |
| Herman Shincel | shince001her | 1904 | 87 g. | Holyoke Paperweights | Connecticut State League | , | |
| Morris Shincup | shinca000--- | 1904 | +8/10+ | Batavia NY | Independent | , | |
| Morris Shincup | shinca000--- | 1904 | 9/23 | Rochester Bronchos | Eastern League | , | |
| Shinners | 1904 | Hudson River League | , | ||||
| Ed. Shinners | shinne001ed- | 1904 | 60 g. | Topeka Saints | Missouri Valley League | , | |
| Bill Shipke | shipke001wil | 1904 | 4/24/-9/25 | Omaha Rangers | Western League | , | |
| Frank Shipp | shipp-000ski | 1904 | +6/27+ | 3 g. | Chattanooga | Tennessee-Alabama League | , |
| Frank Shipp | shipp-000ski | 1904 | Grant University | College | , | ||
| George Shoch | shoch-001geo | 1904 | 5/6-9/27 | Troy Trojans | New York State League | , | |
| G. Herman Shoffner | shoffn001g-- | 1904 | 27 g. | Canton | Delta League | , | |
| Shonberger | schonb001--- | 1904 | +7/7-7/8 | Anniston | Tennessee-Alabama League | , | |
| Ed Shortell | shorte001edw | 1904 | 6/5-6/19 | Binghamton Bingoes | New York State League | , | |
| Ed Shortell | shorte001edw | 1904 | Hoboken NJ | Independent | , | ||
| Eugene Shour | shour-001eug | 1904 | 122 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| Shriver | shrive002--- | 1904 | 5/29 | Centralia Midgets | Southwest Washington League | , | |
| Shriver | shrive002--- | 1904 | +6/12+ | Centralia Clerks | Independent | , | |
| Caleb Shriver | shrive001cal | 1904 | 5/20-8/30 | Wheeling Stogies | Central League | , | |
| William Shufelt | shufel001wil | 1904 | Newburgh Taylor-mades | Hudson River League | , | ||
| Frank Shugart | shugar001fra | 1904 | 4/24-7/23 | Des Moines Prohibitionists | Western League | , | |
| Shultz | 1904 | Peekskill | Hudson River League | , | |||
| Eddie Shultz | shultz001edw | 1904 | 6/8-6/11 | Lebanon | Tri-State League | , | |
| Joseph Sibbick | 1904 | 56 g. | Warren OH | Independent | , | ||
| Johnny Siegle | siegle001joh | 1904 | 5/6-9/18 | Ilion Typewriters | New York State League | , | |
| Herman Siegrist | siegri002--- | 1904 | 5/8-6/12, 8/14 | Umpire | Southwest Washington League | , | |
| Herman Siegrist | siegri002--- | 1904 | 6/19-7/3 | Centralia Midgets | Southwest Washington League | , | |
| Ed Siever | siever001edw | 1904 | St. Louis | American League | St. Louis, MO | ||
| Sigiman | 1904 | +7/28+ | Oklahoma City Mets | Southwestern League | , | ||
| Sigman | 1904 | 7 g. | Ashtabula OH | Independent | , | ||
| Thurse Sigman | sigima001ter | 1904 | Ashland OH | Independent | , | ||
| Thurse Sigman | sigima001ter | 1904 | 41 g. | Hattiesburg | Delta League | , | |
| Hank Simon | simon-001hen | 1904 | 5/10-9/18 | Albany Senators | New York State League | , | |
| Mike Simon | simon-003mic | 1904 | 4/21-9/5 | Columbus Senators | American Association | , | |
| Jack Simons | simons001joh | 1904 | San Francisco | California State League | , | ||
| Jack Simons | simons001joh | 1904 | 1 g. | Portland Browns | Pacific Coast League | , | |
| Ben Simonton | simont001ben | 1904 | +9/13+ | Urbana OH | Independent | , | |
| Oscar Simpson | 1904-05 | +5/3/04+ | Newberry College | College | , | ||
| Oscar Simpson | 1904-05 | Newberry College | College | , | |||
| Lawrence Sinex | sinex-001law | 1904 | 5/28- | Cloudersport PA | Independent | , | |
| Lawrence Sinex | sinex-001law | 1904 | 8/24-9/1 | Coudersport | Southern Tier League | , | |
| Singleton | 1904 | 5/7-5/9+ | Burlington River Rats | Iowa League | , | ||
| Charles Sisler | sisler001cha | 1904 | 4/24-4/26 | St. Joseph Saints | Western League | , | |
| Charles Sisler | sisler001cha | 1904 | 76 g. | Topeka Saints | Missouri Valley League | , | |
| Charles Sisler | sisler001cha | 1904 | Joplin Miners | Missouri Valley League | , | ||
| Charles Sisler | sisler001cha | 1904 | Leavenworth Orioles | Missouri Valley League | , | ||
| Carl Sitton | sitton001car | 1904 | +3/22+ | St. Albans | Academy | , | |
| Carl Sitton | sitton001car | 1904 | no g. | Atlanta Crackers | Southern Association | , | |
| Carl Sitton | sitton001car | 1904 | Birmingham Barons | Southern Association | , | ||
| Sitzer | 1904 | LafayetteCollege | College | , | |||
| Sitzer | 1904 | Corning NY | Independent | , | |||
| Sixsmith | 1904 | 5 g. | Sharon OH | Independent | , | ||
| Edward Skala | skalla001ed- | 1904 | 19 ab | Natchez Indians | Cotton States League | , | |
| Edward Skala | skalla001ed- | 1904 | 51 g. | Brookhaven | Delta League | , | |
| Michael Skanter | 1904 | +7/29-8/6+ | Grand Forks Forkers | Northern League | , | ||
| Michael Skanter | 1904 | 8/12+ | Lake Linden Lakers | Copper Country League | , | ||
| Tom Skelley | skelle001--- | 1904 | Holy Cross | College | , | ||
| Tom Skelley | skelle001--- | 1904 | +7/14+ | Plattsburgh | Northern New York League | , | |
| John Skopec | skopec001joh | 1904 | 5/19-7/29 | Colorado Springs Millionaires | Western League | , | |
| Walt Slagle | slagle001wal | 1904 | 4/21-9/18 | St. Paul Saints | American Association | , | |
| Cyril Slapnicka | 1904-06 | Cedar Rapids HS | High School | , | |||
| Asa Slater | slater001asa | 1904 | 5/1-8/29 | San Antonio Bronchos | South Texas League | , | |
| Ed Slater | slater001hen | 1904 | Holyoke Paperweights | Connecticut State League | , | ||
| Jack Slattery | slatte001joh | 1904 | 4/29-9/20 | Milwaukee Brewers | American Association | , | |
| Thomas Slattery | slatte000tho | 1904 | 8/21-9/2 | Utica Pent-Ups | New York State League | , | |
| Walter Slear | slear-001wal | 1904 | +5/29-8/11+ | Fort Dodge Gypsum Eaters | Iowa League | , | |
| Walter Slear | slear-001wal | 1904 | +8/29-9/5 | Oskaloosa Quakers | Iowa League | , | |
| Ike Slette | slette001isa | 1904 | Superior Longshoremen | Northern League | , | ||
| Jim Smalley | 1904 | Guthrie Blues | Southwestern League | , | |||
| Fred Smeltz | 1904 | Terre Haute Hottentots | Central League | , | |||
| Fred Smeltz | 1904 | 59+ g. | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | ||
| Bill Smink | smink-001wil | 1904 | 290 ab | Baton Rouge Red Sticks | Cotton States League | , | |
| Bill Smink | smink-001wil | 1904 | 8/24 | Toronto Maple Leafs | Eastern League | , | |
| Bill Smink | smink-001wil | 1904 | 9/1-9/12 | Newark Sailors | Eastern League | , | |
| Booker Smiser | smiser000boo | 1904 | +4/29+ | Cumberland Col. | College | , | |
| Booker Smiser | smiser000boo | 1904 | +8/16+ | Colu.-Culleoka | Independent | , | |
| Alfred Smissen | 1904 | 6/22 | Paris Parasites/Ardmore Territorians | Texas League | , | ||
| Smith | smith-361--- | 1904 | 6/29-8/9+ | Addison White Sox | Southern Tier League | , | |
| Smith | 1904 | 8/13 | Corsicana Oil Citys | Texas League | , | ||
| Smith | 1904 | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |||
| Smith | 1904 | +5/12+ | Burlington River Rats | Iowa League | , | ||
| Smith | 1904 | +8/8+ | Burlington River Rats | Iowa League | , | ||
| Smith | 1904 | +7/24+ | Oskaloosa Quakers | Iowa League | , | ||
| Aleck Smith | smith-001ale | 1904 | 10 g. | Chicago | National League | Chicago, IL | |
| Anthony Smith | smith-001ant | 1904 | 4/30-9/2 | Galveston Sand Crabs | South Texas League | , | |
| August Smith | smith-001aug | 1904 | +6/23-7/6+ | Waterloo Microbes | Iowa League | , | |
| Billy Smith | smith-011wil | 1904 | 114 g. | Macon Highlanders | South Atlantic League | , | |
| Billy Smith | smith-057wil | 1904 | 4/21-9/24 | Birmingham Barons | Southern Association | , | |
| Bull Smith | smith-001lew | 1904 | 4/30-8/29 | Wheeling Stogies | Central League | , | |
| Bull Smith | smith-001lew | 1904 | 8/30- | 13 g. | Pittsburgh | National League | Pittsburgh, PA |
| Carlos Smith | smith-006car | 1904 | 217 g. | Seattle Siwashes | Pacific Coast League | , | |
| Charles Smith | 1904 | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |||
| Charlie Smith | smith-011cha | 1904 | 4/23-9/23 | Atlanta Crackers | Southern Association | , | |
| Charlie Smith | smith-057cha | 1904 | +6/27-8/26 | Sault Ste. Marie | Independent | , | |
| Dexter Smith | 1904 | 5/19- | Umpire | Northern League | , | ||
| Dexter Smith | 1904 | 8/31-9/25 | Umpire | Pacific National League | , | ||
| Dick Smith | smith-018ric | 1904 | 79 g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| Dick Smith | smith-005dic | 1904 | 5/10-5/19 | Lebanon | Tri-State League | , | |
| Ed Smith | smith-001rhe | 1904 | 5/10-9/11 | Dayton Veterans | Central League | , | |
| Ed Smith | smith-001ed- | 1904 | San Francisco | California State League | , | ||
| Ed Smith | smith-001ed- | 1904 | Stockton | California State League | , | ||
| Edwin Smith | smith-001g-- | 1904 | 5 g. | Fort Scott Giants | Missouri Valley League | , | |
| Elmer Smith | smith-004elm | 1904 | Johnstown Johnnies | Pennsylvania League | , | ||
| Elmer Smith | smith-004elm | 1904 | 4/27-5/10 | Kansas City Blues | American Association | , | |
| Elmer Smith | smith-004elm | 1904 | 6/3-9/18 | Ilion Typewriters | New York State League | , | |
| Elmer Smith | smith-005elm | 1904 | 86 g. | Springfield Midgets | Missouri Valley League | , | |
| Elmer Smith | smith-005elm | 1904 | Leavenworth Orioles | Missouri Valley League | , | ||
| Frank Smith | smith-008fra | 1904 | Chicago | American League | Chicago, IL | ||
| Frank Smith | smith-004fra | 1904 | 43 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Fred Smith | smith-010fre | 1904 | 5/2-9/11 | Terre Haute Hottentots | Central League | , | |
| George Smith | smith-012geo | 1904 | 4/29-9/28 | Rochester Bronchos | Eastern League | , | |
| George Smith | smith-020geo | 1904 | Oakland | California State League | , | ||
| Germany Smith | smith-013geo | 1904 | +6/16+ | Altoona Mountaineers | Tri-State League | , | |
| Harry Smith | smith-018har | 1904 | 47 g. | Pittsburgh | National League | Pittsburgh, PA | |
| Herbert Smith | smith-005her | 1904 | 5/2-9/11 | South Bend Greens | Central League | , | |
| J. Smith | smith-032j-- | 1904 | 18 g. | Jacksonville Jays | South Atlantic League | , | |
| Joe Smith | smith-007jos | 1904 | +6/16+ | Penn Park PA | Independent | , | |
| Joe Smith | smith-007jos | 1904 | 5/10-9/30 | York Penn Parks | Tri-State League | , | |
| John Smith | smith-024joh | 1904 | 5/11-6/22+ | Altoona Mountaineers | Tri-State League | , | |
| Jud Smith | smith-001jud | 1904 | Los Angeles Angels | Pacific Coast League | , | ||
| Lester Smith | smith-003les | 1904 | 4/30- | Beaumont Millionaires | South Texas League | , | |
| Lester Smith | smith-003les | 1904 | San Antonio Bronchos | South Texas League | , | ||
| Lester Smith | smith-003les | 1904 | -9/2 | Houston Wanderers | South Texas League | , | |
| Madison Smith | smith-001mad | 1904 | 40 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Otto Smith | smith-002ott | 1904 | 8/8 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Phenomenal Smith | smith-013joh | 1904 | 5/12-9/16 | Manchester | New England League | , | |
| Samuel Smith | smith-007sam | 1904 | +6/19-7/24+ | Canton OH | Independent | , | |
| Samuel Smith | smith-007sam | 1904 | +9/18+ | Massillon OH | Independent | , | |
| Stub Smith | smith-001stu | 1904 | 4/23-9/24 | Shreveport Pirates | Southern Association | , | |
| Syd Smith | smith-001syd | 1904 | 118 g. | Charleston Sea Gulls | South Atlantic League | , | |
| Tom Smith | smith-001tho | 1904 | 4/24-9/25 | Denver Grizzlies | Western League | , | |
| Tom Smith | smith-009tom | 1904 | 5/6-7/15 | Nashville Volunteers | Southern Association | , | |
| Tom Smith | smith-009tom | 1904 | 61 ab | Monroe Hill Citys | Cotton States League | , | |
| William Smith | smith-008wil | 1904 | 4/21-9/24 | Birmingham Barons | Southern Association | , | |
| William Smith | smith-079wil | 1904 | Waynesburg Col. | College | , | ||
| Herbert Smithson | donova043--- | 1904 | 5/7-6/21+ | Boone Coal Miners | Iowa League | , | |
| Presley Smithwick | smithw001p-- | 1904 | 5/16-7/6+ | 25 g. | Huntsville | Tennessee-Alabama League | , |
| Homer Smoot | smoot-001hom | 1904 | 137 g. | St. Louis | National League | St. Louis, MO | |
| Harry Smythe | smythe003har | 1904 | New London Whalers | Connecticut State League | , | ||
| Harry Smythe | smythe003har | 1904 | Kingston Colonials | Hudson River League | , | ||
| Harry Smythe | smythe003har | 1904 | 9/9-9/17 | Binghamton Bingoes | New York State League | , | |
| Snodgrass | snodgr004--- | 1904 | 5/16-7/17 | Chattanooga | Tennessee-Alabama League | , | |
| Snodgrass | snodgr004--- | 1904 | +7/20-8/3+ | Sheffield | Tennessee-Alabama League | , | |
| Chappie Snodgrass | snodgr001amz | 1904 | 79 ab | Baton Rouge Red Sticks | Cotton States League | , | |
| Walter Snodgrass | snodgr002wal | 1904 | Newark OH | Independent | , | ||
| George Snoke | snoke-000mas | 1904 | Meriden Silverites | Connecticut State League | , | ||
| George Snoke | snoke-000mas | 1904 | Hartford Senators | Connecticut State League | , | ||
| George Snoke | snoke-000mas | 1904 | 7/14-7/15 | Lebanon | Tri-State League | , | |
| Snook | 1904 | 31 g. | Meriden Silverites | Connecticut State League | , | ||
| Snook | 1904 | Hartford Senators | Connecticut State League | , | |||
| G. Snook | snook-001g-- | 1904 | Pottstown | Pennsylvania League | , | ||
| Harvey Snook | 1904-07 | Lafayette College | College | , | |||
| Joe Snooks | snooks001jos | 1904 | 5/7-9/5 | Marshalltown Grays | Iowa League | , | |
| Roy Snyder | snyder001roy | 1904 | 16 g. | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |
| Scott Snyder | snyder001sco | 1904 | 5/2- | Perry IA | Independent | , | |
| Van Snyder | snyder002c-- | 1904 | 5/6-9/5 | Fort Dodge Gypsum Eaters | Iowa League | , | |
| William Snyder | snyder006wil | 1904 | no g. | Columbus Senators | American Association | , | |
| William Snyder | snyder006wil | 1904 | Decatur | Tennessee-Alabama League | , | ||
| Gus Soffel | soffel001aug | 1904 | 4/30-9/17 | Nashua | New England League | , | |
| Gus Soffel | soffel001aug | 1904 | +7/4+ | Pitts.-PAC | Independent | , | |
| Percy Solbraa | 1904 | Eau Claire WI | Independent | , | |||
| Solenberger | solenb000--- | 1904 | Colo State U. | College | , | ||
| Solenberger | solenb000--- | 1904 | 8/30-9/14 | Colorado Springs Millionaires | Western League | , | |
| Arthur Somers | somers005--- | 1904 | Oxford PA | Independent | , | ||
| Arthur Somers | somers000art | 1904 | 4/28-7/4 | Eugene Blues | Oregon State League | , | |
| Sox Sorber | sorber001wal | 1904 | +6/27-8/2+ | Decatur | Tennessee-Alabama League | , | |
| Walter Sorenson | sorens001wal | 1904 | 5/23 | Grand Forks Forkers | Northern League | , | |
| Walter Sorenson | sorens001wal | 1904 | 5/25 | Crookston Crooks | Northern League | , | |
| Walter Sorenson | sorens001wal | 1904 | 6/19-6/29 | Grand Forks Forkers | Northern League | , | |
| C. Van Sorrell | sorrel003--- | 1904 | 5/16-7/6 | Anniston | Tennessee-Alabama League | , | |
| William Sorrells | sorrel003wil | 1904 | 5/1-9/2 | Houston Wanderers | South Texas League | , | |
| Holly Souders | souder001har | 1904 | 5/11 | Kansas City Blues | American Association | , | |
| Holly Souders | souder001har | 1904 | 5/24- | 10 g. | Fargo | Northern League | , |
| Holly Souders | souder001har | 1904 | 8/12-8/29 | St. Joseph Saints | Western League | , | |
| Walter South | south-001wal | 1904 | 4/27-5/2 | Dallas Giants | Texas League | , | |
| Walter South | south-001wal | 1904 | 5/14- | Kent OH | Independent | , | |
| Arthur Southwell | southw001art | 1904 | 7/28-8/25 | Nashua | New England League | , | |
| John Spaatz | spaatz001joh | 1904 | 4/28- | Dayton Veterans | Central League | , | |
| Bob Spade | spade-001rob | 1904 | Jacksonville Jays | South Atlantic League | , | ||
| Bob Spade | spade-001rob | 1904 | 5/24- | Kent OH | Independent | , | |
| Bob Spade | spade-001rob | 1904 | Warren OH | Independent | , | ||
| Joseph Spaid | 1904-07 | IL Wesleyan College | College | , | |||
| Joseph Spaid | 1904 | Pittsburg Coal Diggers | Missouri Valley League | , | |||
| Alva Spangler | spangl001alv | 1904 | 4/28-9/8 | South Bend Greens | Central League | , | |
| Alva Spangler | spangl001alv | 1904 | 9/10-9/19 | Louisville Colonels | American Association | , | |
| Bill Sparger | sparge001wil | 1904 | Natchez Indians | Cotton States League | , | ||
| James Sparks | sparks001bax | 1904 | 45 g. | Yazoo City Zoos | Delta League | , | |
| James Sparks | sparks001bax | 1904 | 1 g. | Bessemer | Tennessee-Alabama League | , | |
| James Sparks | sparks001bax | 1904 | 9/9 | Memphis Egyptians | Southern Association | , | |
| Frank Spates | spates001fra | 1904 | 128 ab | Baton Rouge Red Sticks | Cotton States League | , | |
| Frank Spates | spates001fra | 1904 | Frostburg | Independent | , | ||
| Carl Speaker | 1904 | Jackson-Marshall | Independent | , | |||
| Spear | 1904 | +5/11-9/3+ | Fort Dodge Gypsum Eaters | Iowa League | , | ||
| Ross Speck | speck-001ros | 1904 | +5/22+ | Bartlesville OK | Independent | , | |
| Charles Speckin | 1904 | +5/26-7/23+ | Oskaloosa Quakers | Iowa League | , | ||
| Speer | speer-002--- | 1904 | 5/16- | 8 g. | Bessemer | Tennessee-Alabama League | , |
| Speer | speer-003--- | 1904 | 5/17- | 1 g. | Anniston | Tennessee-Alabama League | , |
| George Speer | speer-001geo | 1904 | 4/20-9/15 | Milwaukee Brewers | American Association | , | |
| Kid Speer | speer-002geo | 1904 | 42 g. | Springfield Midgets | Missouri Valley League | , | |
| Jack Speery | 1904 | 19 g. | Akron OH | Independent | , | ||
| Jack Speery | 1904 | Canton OH | Independent | , | |||
| William Spelliscy | spelli001wil | 1904 | U. ND Agricultural | College | , | ||
| William Spelliscy | spelli001wil | 1904 | +5/16+ | Fargo ND | Independent | , | |
| William Spelliscy | spelli001wil | 1904 | +7/13+ | Lisbon ND | Independent | , | |
| William Spelliscy | spelli001wil | 1904 | Bismarck SD | Independent | , | ||
| Albert Spencer | spence001alb | 1904 | +5/10-9/5 | Ottumwa Standpatters | Iowa League | , | |
| Clark Spencer | spence001cla | 1904 | 5/22-6/17 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Clark Spencer | spence001cla | 1904 | Denton TX | Independent | , | ||
| Clark Spencer | spence001cla | 1904 | So McAlester | Southwestern League | , | ||
| Collis Spencer | spence001col | 1904 | +5/23-6/22+ | Columbia | Tennessee-Alabama League | , | |
| Collis Spencer | spence001col | 1904 | +6/28-8/3+ | Huntsville | Tennessee-Alabama League | , | |
| Collis Spencer | spence001col | 1904 | -9/1 | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |
| Dit Spencer | spence001d-- | 1904 | 4/27-6/13 | Corsicana Oil Citys | Texas League | , | |
| Dit Spencer | spence001d-- | 1904 | 6/14-7/3 | Umpire | Texas League | , | |
| Dit Spencer | spence001d-- | 1904 | 7/4 | Corsicana Oil Citys | Texas League | , | |
| Dit Spencer | spence001d-- | 1904 | 30 g. | San Antonio Bronchos | South Texas League | , | |
| Frank Spencer | spence001fra | 1904 | 106 g. | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Harry Spencer | spence001hen | 1904 | San Francisco | California State League | , | ||
| Harry Spencer | spence001hen | 1904 | 90 g. | Portland Browns | Pacific Coast League | , | |
| John Spencer | spence001cly | 1904 | 6/- | Columbia | Tennessee-Alabama League | , | |
| John Spencer | spence001cly | 1904 | +6/16-6/30+ | Bessemer | Tennessee-Alabama League | , | |
| John Spencer | spence001cly | 1904 | 7/15-7/19+ | Huntsville | Tennessee-Alabama League | , | |
| Wirt Spencer | spence001wir | 1904 | Umpire | South Texas League | , | ||
| Ed Spies | spies-001ed- | 1904 | 49 g. | Yazoo City Zoos | Delta League | , | |
| Harry Spies | spies-001hen | 1904 | Los Angeles Angels | Pacific Coast League | , | ||
| Matt Spiesman | spiesm002mat | 1904 | 5/6-9/18 | Albany Senators | New York State League | , | |
| Spivine | 1904 | 8/14 | Olympia Senators | Southwest Washington League | , | ||
| George Spooner | spoone001geo | 1904 | 4/20-4/30 | St. Paul Saints | American Association | , | |
| George Spooner | spoone001geo | 1904 | 51 g. | Winnipeg Maroons | Northern League | , | |
| George Spooner | spoone001geo | 1904 | Norwich Reds | Connecticut State League | , | ||
| George Spooner | spoone001geo | 1904 | Holyoke Paperweights | Connecticut State League | , | ||
| Joseph Sporer | sporer001jos | 1904 | 19 g. | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Joseph Sporer | sporer001jos | 1904 | Sault Ste. Marie | Independent | , | ||
| Jack Spratt | spratt001wil | 1904 | 121 g. | Augusta Tourists | South Atlantic League | , | |
| Charles Springer | 1904 | Wash. & Jeff. Col. | College | , | |||
| Charles Springer | 1904 | Washington PA | Independent | , | |||
| Fred Springs | spring001fre | 1904 | 11 g. | Jacksonville Jays | South Atlantic League | , | |
| Roy St. John | stjohn001roy | 1904 | 97 g. | Leavenworth Orioles | Missouri Valley League | , | |
| Jim St. Vrain | stvrai001jam | 1904 | Tacoma Tigers | Pacific Coast League | , | ||
| Cy Stackpole | stackp001art | 1904 | 5/11-7/27 | New Bedford Whalers | New England League | , | |
| Stewart Stader | 1904 | Indianapolis Indians | American Association | , | |||
| Stewart Stader | 1904 | Greenville Cotton Pickers | Cotton States League | , | |||
| John Stafford | staffo001joh | 1904 | 8/9-9/19 | Umpire | New England League | , | |
| Robert Stafford | staffo003rob | 1904 | 4/29-6/5 | Newark Sailors | Eastern League | , | |
| Robert Stafford | staffo003rob | 1904 | 6/9-9/24 | Atlanta Crackers | Southern Association | , | |
| Stagwold | stagwo000--- | 1904 | 8/26 | Fall River Indians | New England League | , | |
| Chick Stahl | stahl-001cha | 1904 | 157 g. | Boston | American League | Boston, MA | |
| Jake Stahl | stahl-001gar | 1904 | 142 g. | Washington | American League | Washington, DC | |
| D. Lee Staley | staley001d-- | 1904 | Mercer College | College | , | ||
| D. Lee Staley | staley001d-- | 1904 | 10 g. | Savannah Pathfinders | South Atlantic League | , | |
| George Stallings | stalli002geo | 1904 | 4/29-9/28 | Buffalo Bisons | Eastern League | , | |
| Everett Stalter | stalte001eve | 1904 | no g. | Ilion Typewriters | New York State League | , | |
| Everett Stalter | stalte001eve | 1904 | 5/6-9/17 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Frederick Stamler | stamle001jam | 1904 | 7/18-8/8 | Hornellsville Maple Cities | Southern Tier League | , | |
| Frederick Stamler | stamle001jam | 1904 | 9/9-9/21 | Providence Grays | Eastern League | , | |
| John Stamm | stamm-001joh | 1904 | 60 g. | Yazoo City Zoos | Delta League | , | |
| Oscar Stanage | stanag001osc | 1904 | Stockton | California State League | , | ||
| Tom Stankard | stanka001tho | 1904 | Holy Cross Col. | College | , | ||
| Tom Stankard | stanka001tho | 1904 | 7/2-7/26 | Pittsburgh | National League | Pittsburgh, PA | |
| Tom Stankard | stanka001tho | 1904 | 7/29-8/13 | Jersey City Skeeters | Eastern League | , | |
| Joe Stanley | stanle003jos | 1904 | 3 g. | Boston | National League | Boston, MA | |
| Joe Stanley | stanle003jos | 1904 | 5/8-5/17 | Providence Grays | Eastern League | , | |
| Joe Stanley | stanle003jos | 1904 | 5/25-9/25 | New Orleans Pelicans | Southern Association | , | |
| Matt Stanley | stanle001mat | 1904 | 18 g. | Portland Browns | Pacific Coast League | , | |
| Matt Stanley | stanle001mat | 1904 | 106 g. | Spokane Indians | Pacific National League | , | |
| Stark | stark-012--- | 1904 | +5/23-8/3+ | Columbia | Tennessee-Alabama League | , | |
| Stark | stark-012--- | 1904 | Sheffield | Tennessee-Alabama League | , | ||
| Claude Stark | stark-001cla | 1904 | 93 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| Claude Stark | stark-001cla | 1904 | +10/28+ | 44 g. | Oakland Oaks | Pacific Coast League | , |
| Dolly Stark | stark-001mon | 1904 | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | ||
| Con Starkel | starke001con | 1904 | 4/27-9/24 | Boise Fruit Pickers | Pacific National League | , | |
| Con Starkel | starke001con | 1904 | +9/30+ | 14 g. | Portland Browns | Pacific Coast League | , |
| George Starnagle | starna001geo | 1904 | 6/17-8/13 | Minneapolis Millers | American Association | , | |
| George Starnagle | starna001geo | 1904 | 9/4-9/25 | Sioux City Soos | Western League | , | |
| A. L. Starr | starr-001a-- | 1904 | 5/21-7/7 | Anniston | Tennessee-Alabama League | , | |
| Harry Stauffer | stauff001hen | 1904 | 37 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Charles Stecher | steche001cha | 1904 | 5/17-9/30 | Lebanon | Tri-State League | , | |
| A. L. Steele | steele013--- | 1904 | 5/8-9/4 | Olympia Senators | Southwest Washington League | , | |
| Carroll Steele | steele002car | 1904 | 5/16-8/2+ | Decatur | Tennessee-Alabama League | , | |
| Fred Steele | steele001fre | 1904 | 7 g. | Pittsburg Coal Diggers | Missouri Valley League | , | |
| Fred Steele | steele001fre | 1904 | 4/22-6/4 | Milwaukee Brewers | American Association | , | |
| Fred Steele | steele001fre | 1904 | 25 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| Farmer Steelman | steelm001mor | 1904 | 141 g. | Portland Browns | Pacific Coast League | , | |
| Clarence Steen | 1904 | Beatrice NE | Independent | , | |||
| Steese | steese001--- | 1904 | Steelton | , | |||
| Michael Steffani | steffa001mic | 1904 | San Jose | California State League | , | ||
| Steinberg | 1904 | 5/6-5/10 | Houston Wanderers | South Texas League | , | ||
| Paul Steinberg | steinb002pau | 1904 | Syra.-All-Collegiates | , | |||
| Chris Steltz | steitz001chr | 1904 | Spokane Indians | Pacific National League | , | ||
| Fred Stem | stem--001fre | 1904-07 | U. of North Carolina | College | , | ||
| Lenard Stephens | stephe001len | 1904 | Bessemer | Tennessee-Alabama League | , | ||
| W. R. Stephens | 1904 | Ellsworth | Independent | , | |||
| Louis Sterling | sterli001lou | 1904 | 5/8 | Utica Pent-Ups | New York State League | , | |
| Louis Sterling | sterli001lou | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| Louis Sterling | sterli001lou | 1904 | 6/29-8/19 | Hornellsville Maple Cities | Southern Tier League | , | |
| Louis Sterling | sterli001lou | 1904 | 7/27-8/2 | Utica Pent-Ups | New York State League | , | |
| Louis Sterling | sterli001lou | 1904 | 9/1-9/9 | Addison White Sox | Southern Tier League | , | |
| Jay Stetler | stetle001per | 1904 | Williamsport Millionaires | Tri-State League | , | ||
| Stevens | 1904 | 7 g. | Alliance OH | Independent | , | ||
| Len Stevens | stephe001len | 1904 | 5/16-7/2+ | Bessemer | Tennessee-Alabama League | , | |
| Stevenson | steven003--- | 1904 | 19 g. | Brookhaven | Delta League | , | |
| John Steventon | steven007joh | 1904 | 4/30-8/12 | Concord Marines | New England League | , | |
| John Steventon | steven007joh | 1904 | 9/5-9/21 | Altoona Mountaineers | Tri-State League | , | |
| Stewart | 1904 | Columbia Skyscrapers | South Atlantic League | , | |||
| Ace Stewart | stewar001ace | 1904 | 4/23-6/14 | New Orleans Pelicans | Southern Association | , | |
| Ace Stewart | stewar001ace | 1904 | 8/5-8/21 | Terre Haute Hottentots | Central League | , | |
| Charles Stewart | stewar001duc | 1904 | 5/6-7/1+ | Fort Dodge Gypsum Eaters | Iowa League | , | |
| Harry Stewart | stewar005har | 1904 | 33 g. | Macon Highlanders | South Atlantic League | , | |
| Harry Stewart | stewar005har | 1904 | Dayton NCR | Independent | , | ||
| Joe Stewart | stewar003jos | 1904 | 6/9-6/11 | Boston | National League | Boston, MA | |
| Joe Stewart | stewar003jos | 1904 | 7/2 | Atlanta Crackers | Southern Association | , | |
| Joe Stewart | stewar003jos | 1904 | 8/4 | Shreveport Pirates | Southern Association | , | |
| Joe Stewart | stewar003jos | 1904 | 9/3-9/19 | Toledo Mud Hens | American Association | , | |
| Henry Stickney | stickn001abr | 1904 | 4/21-6/14 | Montgomery Senators | Southern Association | , | |
| Henry Stickney | stickn001abr | 1904 | 39 g. | Augusta Tourists | South Atlantic League | , | |
| Henry Stickney | stickn001abr | 1904 | Macon Highlanders | South Atlantic League | , | ||
| Henry Stickney | stickn001abr | 1904 | San Francisco | California State League | , | ||
| Will Stickney | stickn001abr | 1904 | 4/21-7/? | Montgomery Senators | Southern Association | , | |
| Will Stickney | stickn001abr | 1904 | Montgomery Senators | Southern Association | , | ||
| Stephen Stift | 1904 | Evansville River Rats | Central League | , | |||
| Leland Stillman | stillm001lee | 1904 | +4/20-5/14+ | Chicago Univ. | College | , | |
| Leland Stillman | stillm001lee | 1904 | 6/24-9/17 | Des Moines Prohibitionists | Western League | , | |
| Archie Stimmel | stimme001arc | 1904 | 4/22-9/20 | Minneapolis Millers | American Association | , | |
| Herbert Stiner | 1904 | Sedalia Goldbugs | Missouri Valley League | , | |||
| George Stinson | stinso001geo | 1904 | 115 g. | Macon Highlanders | South Atlantic League | , | |
| John Stinson | stinso001joh | 1904 | Topeka Saints | Missouri Valley League | , | ||
| John Stinson | stinso001joh | 1904 | Pittsburg Coal Diggers | Missouri Valley League | , | ||
| Stock | stock-005--- | 1904 | 8/21 | Olympia Senators | Southwest Washington League | , | |
| Otis Stocksdale | stocks002oti | 1904 | 4/25-9/24 | Memphis Egyptians | Southern Association | , | |
| Amasa Stollenwerck | stolle001--- | 1904 | Southern Univ. | College | , | ||
| Amasa Stollenwerck | stolle001--- | 1904 | +5/26-6/10+ | Decatur | Tennessee-Alabama League | , | |
| Amasa Stollenwerck | stolle001--- | 1904 | +7/4-7/8+ | Greensboro AL | Independent | , | |
| Amasa Stollenwerck | stolle001--- | 1904 | 7/10- | Selma AL | Independent | , | |
| George Stone | stone-003geo | 1904 | 4/20-9/20 | Milwaukee Brewers | American Association | , | |
| George Stone | 1904 | Umpire | Connecticut State League | , | |||
| Harold Stone | stone-001har | 1904 | Ardmore IT | Independent | , | ||
| Harold Stone | stone-001har | 1904 | 8/5-8/15 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Howard Stone | stone-001how | 1904 | +5/11+ | Newark OH | Independent | , | |
| Herb Stoner | stoner001her | 1904 | 119 g. | Sedalia Goldbugs | Missouri Valley League | , | |
| Herb Stoner | stoner001her | 1904 | 9/19 | Kansas City Blues | American Association | , | |
| John Stoner | 1904 | Yazoo City Zoos | Delta League | , | |||
| Harry Storch | storch001har | 1904 | Kent OH | Independent | , | ||
| George Storey | 1904 | +8/17 | Marshalltown Grays | Iowa League | , | ||
| Tom Stouch | stouch001tom | 1904 | U. of Alabama | College | , | ||
| Tom Stouch | stouch001tom | 1904 | 5/16-8/20 | Decatur | Tennessee-Alabama League | , | |
| Joseph Stoup | stvrai001jam | 1904 | +9/20+ | Elyria OH | Independent | , | |
| George Stovall | stoval001geo | 1904 | 5/7-6/14+ | Burlington River Rats | Iowa League | , | |
| George Stovall | stoval001geo | 1904 | 7/4- | 52 g. | Cleveland | American League | Cleveland, OH |
| Jesse Stovall | stoval001jes | 1904 | Seattle Siwashes | Pacific Coast League | , | ||
| Jesse Stovall | stoval001jes | 1904 | - 10/7 | 25 g. | Detroit | American League | Detroit, MI |
| Stewart Strader | strade001ste | 1904 | 81 ab | Greenville Cotton Pickers | Cotton States League | , | |
| Stewart Strader | strade001ste | 1904 | 36 g. | Macon Highlanders | South Atlantic League | , | |
| Sammy Strang | strang001sam | 1904 | 77 g. | Brooklyn | National League | Brooklyn, NY | |
| Frank Strarup | straru000fra | 1904 | 5/10-5/31 | Umpire | Missouri Valley League | , | |
| Milo Stratton | stratt001mil | 1904 | Woodstock IL | Independent | , | ||
| Milo Stratton | stratt001mil | 1904 | +7/31-8/3+ | Boone Coal Miners | Iowa League | , | |
| Milo Stratton | stratt001mil | 1904 | +8/9-8/11+ | Fort Dodge Gypsum Eaters | Iowa League | , | |
| Strayer | 1904 | 5/8-7/17 | Aberdeen Pippins | Southwest Washington League | , | ||
| Thomas Strayer | straye000tom | 1904 | 5/1-7/4 | Harrisburg Senators | Tri-State League | , | |
| Thomas Strayer | straye000tom | 1904 | Johnstown Johnnies | Pennsylvania League | , | ||
| Thomas Strayer | straye000tom | 1904 | 8/26 | York Penn Parks | Tri-State League | , | |
| Gabby Street | street001cha | 1904 | 4/28-9/10 | Terre Haute Hottentots | Central League | , | |
| Gabby Street | street001cha | 1904 | 9/13- | 11 g. | Cincinnati | National League | Cincinnati, OH |
| Julie Streib | streib001jul | 1904 | San Francisco | California State League | , | ||
| Julie Streib | streib001jul | 1904 | 219 g. | Oakland Oaks | Pacific Coast League | , | |
| Theodore Streib | streib001the | 1904 | 6/18-7/4 | Eugene Blues | Oregon State League | , | |
| Theodore Streib | streib001the | 1904 | 24 g. | Oakland Oaks | Pacific Coast League | , | |
| Oscar Streit | streit001osc | 1904 | 5/4-9/20 | Birmingham Barons | Southern Association | , | |
| Cub Stricker | strick001cub | 1904 | 7/24- | Camden NJ | Independent | , | |
| Elmer Stricklett | strick001elm | 1904 | 5/20-9/20 | Milwaukee Brewers | American Association | , | |
| Elmer Stricklett | strick001elm | 1904 | Chicago | American League | Chicago, IL | ||
| Charles Strobel | strobe001cha | 1904 | Toledo Mud Hens | American Association | , | ||
| Billy Stroh | stroh-001wil | 1904 | 5/6-6/6 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Billy Stroh | stroh-001wil | 1904 | 6/17-6/19 | Utica Pent-Ups | New York State League | , | |
| Billy Stroh | stroh-001wil | 1904 | 8/19 | Syracuse Stars | New York State League | , | |
| George Stroh | stroh-001geo | 1904 | 5/14-9/11 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Herman Strom | strom-001her | 1904 | 5/9-5/14 | Binghamton Bingoes | New York State League | , | |
| Herman Strom | strom-001her | 1904 | 7/1-9/7 | Elmira | Southern Tier League | , | |
| Herman Strom | strom-001her | 1904 | Addison NY | Independent | , | ||
| Ed Strong | strong000ed- | 1904 | 6/9-6/11 | Salt Lake City Elders | Pacific National League | , | |
| Con Strothers | stroth001joh | 1904 | 4/26-7/19 | Augusta Tourists | South Atlantic League | , | |
| Charles Strub | strub-001cha | 1904 | San Francisco | California State League | , | ||
| Dan Stuart | 1904 | Umpire | Central League | , | |||
| Henry Stubblefield | stubbl001hen | 1904 | 100 g. | Houston Wanderers | South Texas League | , | |
| Henry Stubblefield | stubbl001hen | 1904 | San Antonio Bronchos | South Texas League | , | ||
| George Stultz | stultz002geo | 1904 | 4/25-7/26 | Montgomery Senators | Southern Association | , | |
| George Stultz | stultz002geo | 1904 | 8/30-9/17 | Memphis Egyptians | Southern Association | , | |
| Such | such--000--- | 1904 | 7/4 | Penn Yan Grape Pickers | Southern Tier League | , | |
| Frank Suess | suess-001fra | 1904 | 9/9 | Spokane Indians | Pacific National League | , | |
| Frank Suess | suess-001fra | 1904 | 4/29-5/15 | Salem Raglands | Oregon State League | , | |
| Frank Suess | suess-001fra | 1904 | 5/18-7/4 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Frank Suess | suess-001fra | 1904 | Spokane Indians | Pacific National League | , | ||
| Joe Sugden | sugden001jos | 1904 | 105 g. | St. Louis | American League | St. Louis, MO | |
| George Suggs | suggs-001geo | 1904 | 41 g. | Jacksonville Jays | South Atlantic League | , | |
| George Suggs | suggs-001geo | 1904 | 8/13-8/20 | Atlanta Crackers | Southern Association | , | |
| Wilford Sullinger | sullin001f-- | 1904 | Oklahoma City Mets | Southwestern League | , | ||
| Sullivan | sulliv091--- | 1904 | 9/6-9/16 | Little Rock Travelers | Southern Association | , | |
| Andy Sullivan | sulliv001and | 1904 | 9/13 | Boston | National League | Boston, MA | |
| Andy Sullivan | sulliv001and | 1904 | Newport RI | Independent | , | ||
| Andy Sullivan | sulliv001and | 1904 | Fitchburg MA | Independent | , | ||
| Denny Sullivan | sulliv001den | 1904 | 4/20-8/1 | Minneapolis Millers | American Association | , | |
| Denny Sullivan | sulliv001den | 1904 | 9/11 | Minneapolis Millers | American Association | , | |
| F. L. Sullivan | sulliv002f-- | 1904 | Burlington River Rats | Iowa League | , | ||
| F. P. Sullivan | 1904 | 5/20-7/18 | Umpire | New England League | , | ||
| H. Thomas Sullivan | sulliv002h-- | 1904 | 5/7-8/24+ | Waterloo Microbes | Iowa League | , | |
| Jack Sullivan | sulliv023joh | 1904 | Villanova Col | College | , | ||
| Jack Sullivan | sulliv023joh | 1904 | Worcester | Connecticut League | , | ||
| James Sullivan | sulliv018jam | 1904 | 5/8-5/11 | Providence Grays | Eastern League | , | |
| James Sullivan | sulliv018jam | 1904 | 5/23- | Nashua | New England League | , | |
| James Sullivan | sulliv018jam | 1904 | -6/28 | Manchester | New England League | , | |
| James Sullivan | sulliv018jam | 1904 | 8/25-8/28 | Providence Grays | Eastern League | , | |
| Jim Sullivan | sulliv006jam | 1904 | 5/3-9/25 | New Orleans Pelicans | Southern Association | , | |
| Jim Sullivan | sulliv006jam | 1904 | San Francisco | California State League | , | ||
| John Sullivan | sulliv004joh | 1904 | 4/20-9/20 | St. Paul Saints | American Association | , | |
| John Sullivan | sulliv001joh | 1904 | Chicago City League | , | |||
| John Sullivan | sulliv001joh | 1904 | 55 g. | Winnipeg Maroons | Northern League | , | |
| John Sullivan | sulliv005joh | 1904 | 4/27-8/15 | Fort Worth Panthers | Texas League | , | |
| John Sullivan | sulliv013joh | 1904 | Norwich Reds | Connecticut State League | , | ||
| John Sullivan | sulliv001wal | 1904 | 4/27-8/15 | Fort Worth Panthers | Texas League | , | |
| Michael Sullivan | sulliv002mic | 1904 | Norwich Reds | Connecticut State League | , | ||
| Mike Sullivan | sulliv005mic | 1904 | New London Whalers | Connecticut State League | , | ||
| Owen Sullivan | sulliv001owe | 1904 | Newburgh Taylor-mades | Hudson River League | , | ||
| Suter Sullivan | sulliv002sut | 1904 | 5/3-6/11 | Wilmington Peaches | Tri-State League | , | |
| Suter Sullivan | sulliv002sut | 1904 | 6/13-9/20 | Kansas City Blues | American Association | , | |
| Ted Sullivan | sulliv001tp- | 1904 | Calumet Aristocrats | Copper Country League | , | ||
| William Sullivan | 1904 | 4/29-9/28 | Umpire | Eastern League | , | ||
| Sully | sully-001--- | 1904 | +7/2+ | Hamilton | Ohio State League | , | |
| Sully | sully-001--- | 1904 | 8/9-8/15 | Bessemer | Tennessee-Alabama League | , | |
| Summers | 1904 | Oxford | Pennsylvania League | , | |||
| Ed Summers | summer001ora | 1904 | 5/22-5/28 | Wabash College | College | , | |
| Ed Summers | summer001ora | 1904 | 6/4-7/27 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Ollie Summers | summer001oli | 1904 | +7/3-7/15+ | Norwich Reds | Connecticut State League | , | |
| Ollie Summers | summer001oli | 1904 | 8/20-9/28 | Harrisburg Senators | Tri-State League | , | |
| Bill Sump | sump--001wil | 1904 | +4/29+ | 17 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , |
| Bill Sump | sump--001wil | 1904 | In May | 4 g. | Burlington River Rats | Iowa League | , |
| Bill Sump | sump--001wil | 1904 | +7/21-7/23+ | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| E. Sutherland | suther001e-- | 1904 | 47 g. | Hattiesburg | Delta League | , | |
| Jack Sutthoff | suttho001joh | 1904 | 12 g. | Cincinnati | National League | Cincinnati, OH | |
| Jack Sutthoff | suttho001joh | 1904 | 19 g. | Philadelphia | National League | Philadelphia, PA | |
| Larry Sutton | sutton001lar | 1904 | Ilion Typewriters | New York State League | , | ||
| Harry Swacina | swacin001har | 1904 | 121 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| Arthur Swaim | swaim-001art | 1904 | 5/7-9/5+ | Marshalltown Grays | Iowa League | , | |
| Charles Swain | swain-002cha | 1904 | San Jose | California State League | , | ||
| Charles Swain | swain-002cha | 1904 | 3 g. | San Francisco Seals | Pacific Coast League | , | |
| Albert Swalm | swalm-001alb | 1904 | 90 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Harry Swalm | swalm-001har | 1904 | -7/ | 5 g. | Memphis Egyptians | Southern Association | , |
| Arthur Swan | swan--000cas | 1904 | Basin MT | Independent | , | ||
| Arthur Swan | swan--000cas | 1904 | +8/6+ | Helena MT | Independent | , | |
| Oscar Swan | swann-001o-- | 1904 | 4/23-9/16 | Shreveport Pirates | Southern Association | , | |
| Pinky Swander | swande002edw | 1904 | 4/14 | St. Louis | American League | St. Louis, MO | |
| Pinky Swander | swande002edw | 1904 | 4/20-9/20 | Indianapolis Indians | American Association | , | |
| Ivor? Swanson | swanso008--- | 1904 | 8/25-9/11 | Providence Grays | Eastern League | , | |
| Fred Swartzel | 1904 | +7/12+ | Oklahoma City Mets | Southwestern League | , | ||
| Frank Swayne | swayne001fra | 1904 | 5/28- | Coudersport PA | Independent | , | |
| Frank Swayne | swayne001fra | 1904 | Kane | Interstate League | , | ||
| Frank Swayne | swayne001fra | 1904 | 9/7-9/18 | Utica Pent-Ups | New York State League | , | |
| Michael Swayne | swayne001--- | 1904 | 7/22- | Coudersport PA | Independent | , | |
| Michael Swayne | swayne001--- | 1904 | 8/24-9/1 | Coudersport | Southern Tier League | , | |
| Sweeney | 1904 | 10 g. | Youngstown OH | Independent | , | ||
| Alex. Sweeney | sweene001ale | 1904 | 5/5-10/1 | Lebanon | Tri-State League | , | |
| Bill Sweeney | sweene001wil | 1904 | 6/7 | St. Paul Saints | American Association | , | |
| Bill Sweeney | sweene001wil | 1904 | 6/9-7/21 | Toledo Mud Hens | American Association | , | |
| Bill Sweeney | sweene001wil | 1904 | 44 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Edward Sweeney | sweene000ed- | 1904 | Hudson Marines | Hudson River League | , | ||
| Michael Sweeney | sweene009mic | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| Patrick Sweeney | sweene001pat | 1904 | 5/6 | Wheeling Stogies | Central League | , | |
| Patrick Sweeney | sweene001pat | 1904 | Johnstown PA | Independent | , | ||
| Thomas Sweeney | 1904 | Umpire | Hudson River League | , | |||
| Swigert | 1904 | 5/7-6/15 | Umpire | Iowa League | , | ||
| Charlie Swindells | swinde001cha | 1904 | St. Louis | National League | St. Louis, MO | ||
| Charlie Swindells | swinde001cha | 1904 | 76 g. | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Swinford | 1904 | 9/6 | Terre Haute Hottentots | Central League | , | ||
| Ed Switzer | switze001j-- | 1904 | 20 g. | San Antonio Bronchos | South Texas League | , | |
| Walter Swope | swope-001wal | 1904 | 5/2-9/16 | Nashua | New England League | , | |
| Len Swormstedt | sworms001leo | 1904 | 4/22-6/6 | Louisville Colonels | American Association | , | |
| Len Swormstedt | sworms001leo | 1904 | 7/25-8/1 | Louisville Colonels | American Association | , | |
| Len Swormstedt | sworms001leo | 1904 | 8/31 | Harrisburg Senators | Tri-State League | , | |
| Edward Sykes | sykes-010--- | 1904 | 17 g. | Piqua OH | Independent | , | |
| Louis Sylvester | sylves001lou | 1904 | 4/30-5/14 | Manchester | New England League | , | |
| Charles Symons | symons000cy- | 1904 | 5/19-7/13 | Superior Longshoremen | Northern League | , | |
| Charles Symons | symons000cy- | 1904 | 8/13 | Crookston Crooks | Northern League | , | |
| Charles Symons | symons000cy- | 1904 | +9/4-9/11+ | Two Harbors MN | Independent | , | |
| Charles Symons | symons000cy- | 1904 | +10/2+ | Hibbing MN | Independent | , | |
| William Taaffe | taffee001w-- | 1904 | Vandalia IL | Independent | , | ||
| William Taaffe | taffee001w-- | 1904 | 9/3-9/10+ | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Harry Tackaberry | tackab001har | 1904 | 114 ab | Pine Bluff Lumbermen | Cotton States League | , | |
| Harry Tackaberry | tackab001har | 1904 | +10/2+ | Fort Worth Panthers | Texas League | , | |
| Harry Tackaberry | tackab001har | 1904 | 6/24 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Harry Tackaberry | tackab001har | 1904 | 6/30-7/22 | Umpire | Texas League | , | |
| Harry Tackaberry | tackab001har | 1904 | 7/23-7/24 | Corsicana Oil Citys | Texas League | , | |
| Harry Tackaberry | tackab001har | 1904 | 7/26-7/28 | Fort Worth Panthers | Texas League | , | |
| Harry Tackaberry | tackab001har | 1904 | +10/2+ | Fort Worth Panthers | Texas League | , | |
| James Tamsett | tamset001jam | 1904 | 4/21-9/24 | Birmingham Barons | Southern Association | , | |
| J. C. Tannehill | 1904 | Wheeling Stogies | Central League | , | |||
| Eugene Tansey | tansey001eug | 1904 | 72 g. | Springfield Ponies | Connecticut State League | , | |
| Robert Tarleton | tarlet001rob | 1904 | Baton Rouge Red Sticks | Cotton States League | , | ||
| Robert Tarleton | tarlet001rob | 1904 | 58 g. | Yazoo City Zoos | Delta League | , | |
| James Tarr | tarr--000jam | 1904 | Shawnee Browns/Chickasha Indians | Southwestern League | , | ||
| Harry Tate | tate--001har | 1904 | 5/17-6/22 | Lebanon | Tri-State League | , | |
| Hughie Tate | tate--001hug | 1904 | Homestead PA | Independent | , | ||
| Hughie Tate | tate--001hug | 1904 | Cumberland MD | Independent | , | ||
| Taylor | taylor100--- | 1904 | 5/3-5/4 | Providence Grays | Eastern League | , | |
| Taylor | taylor099--- | 1904 | 9/8 | Rochester Bronchos | Eastern League | , | |
| Taylor | taylor091--- | 1904 | 5/3-5/11 | Fall River Indians | New England League | , | |
| Taylor | taylor059--- | 1904 | 5 ab | Natchez Indians | Cotton States League | , | |
| Taylor | taylor008--- | 1904 | +6/17+ | Huntsville | Tennessee-Alabama League | , | |
| Billy Taylor | taylor002bil | 1904 | 5/1-9/30 | Harrisburg Senators | Tri-State League | , | |
| E. W. Taylor | 1904 | Wheeling Stogies | Central League | , | |||
| Earl Taylor | taylor001ear | 1904 | Leavenworth Orioles | Missouri Valley League | , | ||
| Ed Taylor | taylor001edg | 1904 | 5/8-6/19 | San Antonio Bronchos | South Texas League | , | |
| Eddie Taylor | taylor001edd | 1904 | Charlestown WV | Independent | , | ||
| Frederick Taylor | taylor003fre | 1904 | Newburgh Taylor-mades | Hudson River League | , | ||
| George Taylor | 1904 | Omaha Rangers | Western League | , | |||
| Harry Taylor | taylor005jac | 1904 | Winchester IN | Independent | , | ||
| John Taylor | taylor107--- | 1904 | +5/11-8/3+ | Marshalltown Grays | Iowa League | , | |
| Luther Taylor | taylor001lut | 1904 | New York | National League | New York, NY | ||
| M. Owen Taylor | taylor001m-- | 1904 | +6/27-8/26+ | Sault Ste. Marie | Independent | , | |
| Slats Taylor | taylor002vir | 1904 | 4/28-5/15 | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Slats Taylor | taylor002vir | 1904 | 5/18-6/26+ | Vancouver Soldiers/Albany Rollers | Oregon State League | , | |
| Wally Taylor | taylor001wal | 1904 | 4/23-4/26 | Little Rock Travelers | Southern Association | , | |
| Wally Taylor | taylor001wal | 1904 | 6/1-9/17 | Manchester | New England League | , | |
| George Te Linde | 1904 | +9/13+ | Painesville OH | Independent | , | ||
| George Te Linde | 1904 | +10/16-10/23+ | Euclid Beach | Independent | , | ||
| Harry Teal | teal--002har | 1904 | no g. | Fort Wayne Railroaders | Central League | , | |
| Harvey Teal | teal--003har | 1904 | no g. | Toledo Mud Hens | American Association | , | |
| Harvey Teal | teal--003har | 1904 | +8/5+ | Montpelier OH | Independent | , | |
| Robert Teas | teas--001rob | 1904 | 8/10 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Robert Teas | teas--001rob | 1904 | +8/23 | Wichita Falls | Western Texas | , | |
| George Tebeau | tebeau002geo | 1904 | 4/20-9/20 | Louisville Colonels | American Association | , | |
| Delbert Teel | teel--001d-- | 1904 | 5/6-9/5 | Ottumwa Standpatters | Iowa League | , | |
| Richard Teela | teela-000ric | 1904 | Oshk.-Struebing | Independent | , | ||
| Harry Tempany | tempan000har | 1904 | Spokane Indians | Pacific National League | , | ||
| Harry Tempany | tempan000har | 1904 | 6/26-7/4 | Eugene Blues | Oregon State League | , | |
| Templeton | temple003--- | 1904 | Corsicana Oil Citys | Texas League | , | ||
| Curt Templin | templi001cur | 1904 | -5/24 | Chester | Pennsylvania League | , | |
| Curt Templin | templi001cur | 1904 | Oxford | Pennsylvania League | , | ||
| Curt Templin | templi001cur | 1904 | 9/15 | Providence Grays | Eastern League | , | |
| Terrell | 1904 | 36 g. | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | ||
| Terrell | 1904 | 7/22 | San Antonio Bronchos | South Texas League | , | ||
| Ralph Terry | 1904 | Kalamazoo College | College | , | |||
| Ivey Tevis | tevis-001iva | 1904 | 5/20-6/6 | Houston Wanderers | South Texas League | , | |
| Parry Thackara | thacka001dav | 1904 | Pottstown | Pennsylvania League | , | ||
| Grant Thatcher | thatch001uly | 1904 | 4/24 | Brooklyn | National League | Brooklyn, NY | |
| Grant Thatcher | thatch001uly | 1904 | 27 g. | Savannah Pathfinders | South Atlantic League | , | |
| Tony Thebo | thebo-001ant | 1904 | 4/27-6/30 | Corsicana Oil Citys | Texas League | , | |
| Tony Thebo | thebo-001ant | 1904 | 55 g. | Beaumont Millionaires | South Texas League | , | |
| Joseph Theisen | theise001jos | 1904 | Meriden Silverites | Connecticut State League | , | ||
| George Therre | therre001geo | 1904 | 5/11-9/18 | Ilion Typewriters | New York State League | , | |
| Otto Thiel | thiel-001ott | 1904 | 4/24-7/26 | Des Moines Prohibitionists | Western League | , | |
| Otto Thiel | thiel-001ott | 1904 | 7/28-9/21 | Omaha Rangers | Western League | , | |
| Henry Thielman | thielm001hen | 1904 | 5/2-9/15 | Jersey City Skeeters | Eastern League | , | |
| Jake Thielman | thielm001joh | 1904 | 4/26 | Portland Browns | Pacific Coast League | , | |
| Jack Thiery | thiery001joh | 1904 | 93 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| Maurice Thoits | 1904 | 8/1 | Lowell Tigers | New England League | , | ||
| Thomas | thomas037--- | 1904 | +8/26+ | Lake Linden Lakers | Copper Country League | , | |
| Thomas | thomas047--- | 1904 | 6/2-6/25+ | Anniston | Tennessee-Alabama League | , | |
| Alphonse Thomas | thomas002alp | 1904 | Meriden Silverites | Connecticut State League | , | ||
| Bill Thomas | thomas007wil | 1904 | 5/10-7/11 | Lebanon | Tri-State League | , | |
| Bill Thomas | thomas007wil | 1904 | 7/12-7/19 | Harrisburg Senators | Tri-State League | , | |
| Bill Thomas | thomas007wil | 1904 | 7/26-8/5 | Wilmington Peaches | Tri-State League | , | |
| Clifford Thomas | thomas001cli | 1904 | 5/16- | 6 g. | Huntsville | Tennessee-Alabama League | , |
| Clifford Thomas | thomas001cli | 1904 | 6/ | Columbia | Tennessee-Alabama League | , | |
| Dick Thomas | thomas000re- | 1904 | 4/30-8/28 | San Antonio Bronchos | South Texas League | , | |
| Frosty Thomas | thomas001for | 1904 | 4/20-9/18 | Minneapolis Millers | American Association | , | |
| Ira Thomas | thomas001ira | 1904 | 4/30-6/23 | Providence Grays | Eastern League | , | |
| Ira Thomas | thomas001ira | 1904 | 8/1-8/28 | Providence Grays | Eastern League | , | |
| Jack Thomas | thomas007joh | 1904 | 4/24-9/25 | Omaha Rangers | Western League | , | |
| James Thomas | thomas002jim | 1904 | +5/29-9/5 | Lake Linden Lakers | Copper Country League | , | |
| Joe Thomas | thomas001tho | 1904 | 33 g. | Crookston Crooks | Northern League | , | |
| Joe Thomas | thomas001tho | 1904 | 8/21- | 12 g. | Salt Lake City Elders | Pacific National League | , |
| Orth Thomas | thomas001ort | 1904 | 5/1-5/31 | Galveston Sand Crabs | South Texas League | , | |
| Orth Thomas | thomas001ort | 1904 | 6/5-8/4 | Houston Wanderers | South Texas League | , | |
| Roy Thomas | thomas002roy | 1904 | Philadelphia | National League | Philadelphia, PA | ||
| Tom Thomas | thomas005tho | 1904 | 5/19- | 33 g. | Crookston Crooks | Northern League | , |
| William Thomas | thomas002wil | 1904 | Tacoma Tigers | Pacific Coast League | , | ||
| Thompson | thomps087--- | 1904 | Ottawa Univ. | College | , | ||
| Thompson | thomps087--- | 1904 | 21 g. | Topeka Saints | Missouri Valley League | , | |
| Thompson | 1904 | 7/8- | Wellsville Oil Drillers | Southern Tier League | , | ||
| Gus Thompson | thomps007joh | 1904 | 39 g. | Boise Fruit Pickers | Pacific National League | , | |
| Jack Thompson | thomps011joh | 1904 | 4/28-9/11 | Terre Haute Hottentots | Central League | , | |
| M. J. Thompson | thomps002m-- | 1904 | 36 g. | Norwich Reds | Connecticut State League | , | |
| Jack Thoney | thoney001joh | 1904 | 17 g. | Washington | American League | Washington, DC | |
| Jack Thoney | thoney001joh | 1904 | 36 g. | New York | American League | New York, NY | |
| Jack Thoney | thoney001joh | 1904 | 7/1-8/4 | Rochester Bronchos | Eastern League | , | |
| Jack Thoney | thoney001joh | 1904 | 8/31-9/29 | Montreal Royals | Eastern League | , | |
| John Thornton | thornt003joh | 1904 | 4/24-9/25 | Colorado Springs Millionaires | Western League | , | |
| Ross Thornton | thornt001ros | 1904 | 114 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Ross Thornton | thornt001ros | 1904 | 7/15- | Columbus Senators | American Association | , | |
| Ross Thornton | thornt001ros | 1904 | Rock Island Islanders | Illinois-Indiana-Iowa League | , | ||
| Woody Thornton | thornt002woo | 1904 | 46 g. | Augusta Tourists | South Atlantic League | , | |
| Woody Thornton | thornt002woo | 1904 | Columbia Skyscrapers | South Atlantic League | , | ||
| William Thum | thum--001wil | 1904 | Evansville River Rats | Central League | , | ||
| Pat Tibald | tibald001pet | 1904 | 4/28-8/28 | Terre Haute Hottentots | Central League | , | |
| James Tibbetts | tibbet002jam | 1904 | 5/22-8/25 | Fall River Indians | New England League | , | |
| James Tibbetts | tibbet002jam | 1904 | +8/30-9/30 | Lebanon | Tri-State League | , | |
| George Tieman | tieman001geo | 1904 | 4/28-9/11 | South Bend Greens | Central League | , | |
| Tierney | tierne004mar | 1904 | 6/9 | Wilmington Peaches | Tri-State League | , | |
| Mark Tierney | tierne001edw | 1904 | 6/25- | Lawrence Colts | New England League | , | |
| Mark Tierney | tierne001edw | 1904 | -9/17 | Lowell Tigers | New England League | , | |
| Jack Tighe | tighe-001joh | 1904 | 36 g. | Norwich Reds | Connecticut State League | , | |
| Jack Tighe | tighe-001joh | 1904 | 7/18-9/19 | New Bedford Whalers | New England League | , | |
| William Tiley | 1904 | 5/6-6/16 | Oskaloosa Quakers | Iowa League | , | ||
| William Tiley | 1904 | 7/7-9/5 | Umpire | Iowa League | , | ||
| Jimmy Tilford | tilfor001jam | 1904 | 21 g. | Clarksdale | Delta League | , | |
| Joe Tilford | tilfor001joe | 1904 | 5/27-6/5 | Umpire | Texas League | , | |
| John Titus | titus-001joh | 1904 | Philadelphia | National League | Philadelphia, PA | ||
| Stanley Titus | titus-004--- | 1904 | Georgetown Med | College | , | ||
| Stanley Titus | titus-004--- | 1904 | +6/26+ | 14 g. | Salt Lake City Elders | Pacific National League | , |
| Stanley Titus | titus-004--- | 1904 | Spokane Indians | Pacific National League | , | ||
| Stanley Titus | titus-004--- | 1904 | 9/4 | Centralia Midgets | Southwest Washington League | , | |
| Walter Tobin | tobin-001wal | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| E. H. Todd | todd--001o-- | 1904 | +5/15+ | 15 g. | Vincennes Reds | Kentucky-Illinois-Tennessee League | , |
| E. H. Todd | todd--001o-- | 1904 | by 7/21 | Sheffield | Tennessee-Alabama League | , | |
| Junius Todd | todd--000jun | 1904 | 4/30 | Fort Wayne Railroaders | Central League | , | |
| Jack Toft | toft--001jam | 1904 | 4/30 | Toronto Maple Leafs | Eastern League | , | |
| Jack Toft | toft--001jam | 1904 | 6/26-8/24 | Providence Grays | Eastern League | , | |
| Jack Toft | toft--001jam | 1904 | 9/17-9/26 | Providence Grays | Eastern League | , | |
| Jimmy Toman | toman-001jam | 1904 | 193 g. | Los Angeles Angels | Pacific Coast League | , | |
| Tompkins | 1904 | Hattiesburg | Delta League | , | |||
| Thomas Toner | toner-001tho | 1904 | 436 ab | Vicksburg Hill Billies | Cotton States League | , | |
| James Toohey | 1904 | Leavenworth Orioles | Missouri Valley League | , | |||
| Albert Tooley | 1904 | Howell MI | High School | , | |||
| Roy Toren | toren-002roy | 1904 | 6/24-6/30 | Grand Rapids Orphans | Central League | , | |
| Cy Torrence | torren001osc | 1904 | 13 g. | Charleston Sea Gulls | South Atlantic League | , | |
| Cy Torrence | torren001osc | 1904 | Umpire | South Atlantic League | , | ||
| Will Torrence | torren002wil | 1904 | +7/16+ | Pittsburg Coal Diggers | Missouri Valley League | , | |
| William Torrence | torren002wil | 1904 | Pittsburg Coal Diggers | Missouri Valley League | , | ||
| William Torrence | torren002wil | 1904 | 82 g. | Joplin Miners | Missouri Valley League | , | |
| William Torrence | torren002wil | 1904 | +9/25+ | Oklahoma CityOT | Independent | , | |
| Clarence Totman | totman001cla | 1904 | 39 g. | Chicago Junction | Independent | , | |
| Clarence Totman | totman001cla | 1904 | 8/17- | Canton OH | Independent | , | |
| Clarence Totman | totman001cla | 1904 | Akron OH | Independent | , | ||
| Joseph Touhey | toohey001jos | 1904 | 5/6-5/8 | Utica Pent-Ups | New York State League | , | |
| Joseph Touhey | toohey001jos | 1904 | 6/17-6/21 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Joseph Touhey | toohey001jos | 1904 | 7/1-8/19 | Hornellsville Maple Cities | Southern Tier League | , | |
| W. C. Touhey | 1904 | Paterson Intruders | Hudson River League | , | |||
| Walter Towers | towers001wal | 1904 | 12 g. | Springfield Midgets | Missouri Valley League | , | |
| Babe Towne | towne-001jay | 1904 | 4/24-9/25 | Des Moines Prohibitionists | Western League | , | |
| Cy Townsend | townse002cha | 1904 | Lodi | California State League | , | ||
| Cy Townsend | townse002cha | 1904 | 59 g. | San Francisco Seals | Pacific Coast League | , | |
| Guy Townsend | townse001guy | 1904 | 5/7-6/13+ | Keokuk Indians | Iowa League | , | |
| Happy Townsend | townse001joh | 1904 | 38 g. | Washington | American League | Washington, DC | |
| Zob Townsend | townse000zob | 1904 | Beatrice NE | Independent | , | ||
| Bill Tozer | tozer-001wil | 1904 | 66 g. | Salt Lake City Elders | Pacific National League | , | |
| Tracy | tracy-011--- | 1904 | 9/11 | Butte Miners/Fruit Pickers | Pacific National League | , | |
| John Tracy | tracy-002joh | 1904 | 5/2-5/3 | Montreal Royals | Eastern League | , | |
| John? Tracy | tracy-014--- | 1904 | 5/17-5/30 | Wilmington Peaches | Tri-State League | , | |
| Robert Tracy | 1904 | Hartford Senators | Connecticut State League | , | |||
| William Tracy | 1904 | Hartford Senators | Connecticut State League | , | |||
| Charles Traeger | traege002cha | 1904 | 5/19- | 67 g. | Fargo | Northern League | , |
| James Trainor | traino001jam | 1904 | 5/26-9/17 | Syracuse Stars | New York State League | , | |
| George Treadway | treadw001geo | 1904 | Portland Browns | Pacific Coast League | , | ||
| Wix Treadway | treadw001win | 1904 | 5/7-6/15 | Marshalltown Grays | Iowa League | , | |
| Trestrall | trestr001--- | 1904 | +9/26+ | KC-Thomas Blues | Independent | , | |
| Benjamin Tribble | 1904 | Macon Highlanders | South Atlantic League | , | |||
| Robert Tritton | tritto001rob | 1904 | 4/23 | Birmingham Barons | Southern Association | , | |
| Robert Tritton | tritto001rob | 1904 | 5/6-6/1 | Montgomery Senators | Southern Association | , | |
| Robert Tritton | tritto001rob | 1904 | +7/4+ | Columbia | Tennessee-Alabama League | , | |
| Robert Tritton | tritto001rob | 1904 | Charleston Sea Gulls | South Atlantic League | , | ||
| B. Trobough | 1904 | +5/25+ | Tobias NE | Independent | , | ||
| Del Trobough | trobou001del | 1904 | 5/7-6/13 | Burlington River Rats | Iowa League | , | |
| Del Trobough | trobou001del | 1904 | +7/12+ | Ord NE | Independent | , | |
| Del Trobough | trobou001del | 1904 | Humphrey NE | Independent | , | ||
| Thad Troy | troy--001tha | 1904 | -7/16 | 14 g. Mgr. | Piqua OH | Independent | , |
| Thad Troy | troy--001tha | 1904 | 8/2-8/4 | Wheeling Stogies | Central League | , | |
| Harry Truby | truby-002har | 1904 | 118 g. | Augusta Tourists | South Atlantic League | , | |
| Harry Truby | truby-002har | 1904 | Savannah Pathfinders | South Atlantic League | , | ||
| Truesdall | 1904 | Peekskill | Hudson River League | , | |||
| Charles Truitt | 1904 | 7/3-7/27 | Grand Rapids Orphans | Central League | , | ||
| Jonathan Trumbull | trumbu002--- | 1904 | New Haven Blues | Connecticut State League | , | ||
| Jonathan Trumbull | trumbu002--- | 1904 | +5/30+ | Waterbury CT | Independent | , | |
| Dave Tucker | tucker001dav | 1904 | 5/7-6/21 | Boone Coal Miners | Iowa League | , | |
| Tom Tuckey | tuckey002tho | 1904 | 28 g. | New Haven Blues | Connecticut State League | , | |
| Henry Tufts | tufts-001hen | 1904 | 10 g. | Fargo | Northern League | , | |
| Tullar | tullar000--- | 1904 | 4/27-6/16 | Fort Worth Panthers | Texas League | , | |
| Tullar | tullar000--- | 1904 | 6/18-7/4 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Tullar | tullar000--- | 1904 | +9/25+ | Oklahoma City Mets | Southwestern League | , | |
| Paddy Tuohy | toohey001jam | 1904 | Paterson Intruders | Hudson River League | , | ||
| Turner | turner013--- | 1904 | 7/26-8/2 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Daniel Turner | turner003dan | 1904 | 5/9-7/15 | New Orleans Pelicans | Southern Association | , | |
| T. T. Turner | turner001t-- | 1904 | 15 g. | Jackson Senators | Delta League | , | |
| Terry Turner | turner001ter | 1904 | Cleveland | American League | Cleveland, OH | ||
| Tuck Turner | turner002tuc | 1904 | Norwich Reds | Connecticut State League | , | ||
| William Turnipseed | 1904 | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | |||
| Harvey Tustin | 1904 | Allegheny Prep | High School | , | |||
| John Ulmer | 1904 | Oklahoma City Mets | Southwestern League | , | |||
| Fred Ulrich | ulrich001fre | 1904 | 79 g. | Leavenworth Orioles | Missouri Valley League | , | |
| Bob Unglaub | unglau002rob | 1904 | 4/15- | 6 g. | New York | American League | New York, NY |
| Bob Unglaub | unglau002rob | 1904 | 9 g. | Boston | American League | Boston, MA | |
| Tommy Uniac | uniac-001tho | 1904 | +7/14-8/24+ | St. Albans | Northern New York League | , | |
| George Upp | upp---001geo | 1904 | Warren OH | Independent | , | ||
| Bill Urquhart | urquha001wil | 1904 | 5/9-7/12 | Syracuse Stars | New York State League | , | |
| Bill Urquhart | urquha001wil | 1904 | 7/21-9/17 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Lon Ury | ury---001lou | 1904 | 4/27-8/15 | Dallas Giants | Texas League | , | |
| Jerome Utley | utley-001jer | 1904 | U. of Michigan | College | , | ||
| Jerome Utley | utley-001jer | 1904 | +6/16-9/5 | Portage Lake | Copper Country League | , | |
| Harry Vahrenhorst | vahren001har | 1904 | 9/21 | St. Louis | American League | St. Louis, MO | |
| Bob Vail | vail--001rob | 1904 | +4/11+ | Davidson Col. | College | , | |
| Bob Vail | vail--001rob | 1904 | 6/9, 7/9 | Nashua | New England League | , | |
| Fred Valdois | valdoi001fre | 1904 | 4/30-9/10 | New Bedford Whalers | New England League | , | |
| Edward Van Anda | vanand002edw | 1904 | 7/18-9/9 | Fort Wayne Railroaders | Central League | , | |
| Deacon Van Buren | vanbur001edw | 1904 | 5/19-7/17 | Kansas City Blues | American Association | , | |
| Deacon Van Buren | vanbur001edw | 1904 | Brooklyn | National League | Brooklyn, NY | ||
| Deacon Van Buren | vanbur001edw | 1904 | 12 g. | Philadelphia | National League | Philadelphia, PA | |
| Deacon Van Buren | vanbur001edw | 1904 | 101 g. | San Francisco Seals | Pacific Coast League | , | |
| Dow Van Dine | vandin001dow | 1904 | 120 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| William Van Leuwen | vanleu000wil | 1904 | 6/9-6/12 | Roseburg Shamrocks | Oregon State League | , | |
| George Van Riper | 1904 | Pate.-Olympics | Independent | , | |||
| Sam Van Sickle | 1904 | Louisville Colonels | American Association | , | |||
| Sam Van Sickle | 1904 | +5/19-5/25+ | Sheffield | Tennessee-Alabama League | , | ||
| Ike Van Zandt | vanzan001cha | 1904 | 4/30-9/17 | Nashua | New England League | , | |
| Ike Van Zandt | vanzan001cha | 1904 | 3 g. | Chicago | National League | Chicago, IL | |
| George Vandegrift | vandeg001geo | 1904 | 6/4-7/22 | New Bedford Whalers | New England League | , | |
| George Vandegrift | vandeg001geo | 1904 | 7/25-9/28 | Jersey City Skeeters | Eastern League | , | |
| Anthony Vanderhill | vander001ant | 1904 | 119 g. | Joplin Miners | Missouri Valley League | , | |
| Joseph Varner | varner001j-- | 1904 | Johnstown PA | Independent | , | ||
| Dike Varney | varney001law | 1904 | , | ||||
| Cal Vasbinder | vasbin001mos | 1904 | 5/12-5/22 | Atlanta Crackers | Southern Association | , | |
| Cal Vasbinder | vasbin001mos | 1904 | 15 g. | Butte Miners/Fruit Pickers | Pacific National League | , | |
| William Vaughan | 1904 | Mt. Carmel | , | ||||
| Vaughn | vaughn013--- | 1904 | 41 ab | Baton Rouge Red Sticks | Cotton States League | , | |
| Vaughn | vaughn018--- | 1904 | 5/10-6/11 | Camden | Tri-State League | , | |
| Farmer Vaughn | vaughn001far | 1904 | Auburn Univ. | College | , | ||
| Farmer Vaughn | vaughn001far | 1904 | 4/30-9/23 | Birmingham Barons | Southern Association | , | |
| Merrill Vaughn | vaughn001mer | 1904 | 66 g. | Brookhaven | Delta League | , | |
| Perry Vaughn | vaughn000per | 1904 | +5/4+ | Kingman KS | Independent | , | |
| Bucky Veil | veil--001fre | 1904 | 4/23 | Pittsburgh | National League | Pittsburgh, PA | |
| Bucky Veil | veil--001fre | 1904 | 5/11-8/11+ | Altoona Mountaineers | Tri-State League | , | |
| William Veley | 1904 | +7/3+ | Spok.-R & L | Independent | , | ||
| Charles Venable | venabl001cha | 1904 | Wash DC- Comm. | Independent | , | ||
| Perry Verga | verga-001geo | 1904 | Oxford PA | Independent | , | ||
| Lee Vernuelle | vernue001rob | 1904 | Pine Bluff Lumbermen | Cotton States League | , | ||
| Theodore Vetter | vetter008--- | 1904 | +5/28+ | St. Bonaventure | College | , | |
| Theodore Vetter | vetter008--- | 1904 | +6/21-7/11+ | Hornellsville Maple Cities | Southern Tier League | , | |
| Lee Viau | viau--001lee | 1904 | 5/2-8/7 | Montreal Royals | Eastern League | , | |
| Lee Viau | viau--001lee | 1904 | 8/24 | Providence Grays | Eastern League | , | |
| Rube Vickers | vicker001har | 1904 | 31 g. | Holyoke Paperweights | Connecticut State League | , | |
| Mathew Vidovich | vidovi001m-- | 1904 | Galv.-Denvers | Independent | , | ||
| George Villeman | villem001geo | 1904 | 5/28-9/25 | Colorado Springs Millionaires | Western League | , | |
| Rube Vinson | vinson001ern | 1904 | 5/1-7/3 | Harrisburg Senators | Tri-State League | , | |
| Rube Vinson | vinson001ern | 1904 | 7/7-9/22 | Providence Grays | Eastern League | , | |
| Rube Vinson | vinson001ern | 1904 | 9/27 - | 15 g. | Cleveland | American League | Cleveland, OH |
| Juan Viola | 1904 | 97 g. | Jacksonville Jays | South Atlantic League | , | ||
| Juan Viola | 1904 | 10 g. | Habana | Cuban Winter League | , | ||
| Juan Viola | 1904 | 3 g. | Habana | CNCS | , | ||
| Juan Viola | 1904 | 2 g. | Carmelita | Cuban League | , | ||
| Frank Violet | violet001fra | 1904 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | ||
| John Violet | 1904 | Jacksonville | , | ||||
| Ernest Virgils | virgil000ern | 1904 | Paducah Indians | Kentucky-Illinois-Tennessee League | , | ||
| Ernest Virgils | virgil000ern | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | ||
| Harry Vitter | vitter001har | 1904 | 58 g. | Canton | Delta League | , | |
| Roland Vitter | vitter001rol | 1904 | 22 g. | Brookhaven | Delta League | , | |
| James Vizard | vizard001jam | 1904 | -8/10 | Lake Linden Lakers | Copper Country League | , | |
| George Volk | volk--001geo | 1904 | 56 g. | Marietta OH | Independent | , | |
| George Volk | volk--001geo | 1904 | Kent OH | Independent | , | ||
| George Volk | volk--001geo | 1904 | Barberton OH | Independent | , | ||
| Jim Vollendorf | vollen001ado | 1904 | 4/25-9/21 | Denver Grizzlies | Western League | , | |
| Jake Volz | volz--001jac | 1904 | 5/4-9/16 | Manchester | New England League | , | |
| Cy Vorhees | vorhee001hen | 1904 | Holyoke Paperweights | Connecticut State League | , | ||
| Bobby Vorpagel | vorpag001rob | 1904 | +8/20+ | Lake Linden Lakers | Copper Country League | , | |
| William Vought | vought002wil | 1904 | no g. | Kingston Colonials | Hudson River League | , | |
| William Vought | vought002wil | 1904 | Johnstown Johnnies | Pennsylvania League | , | ||
| William Vought | vought002wil | 1904 | Pottstown | Pennsylvania League | , | ||
| Rip Vowinkel | vowink001joh | 1904 | 5/9-9/16 | Utica Pent-Ups | New York State League | , | |
| Joseph Vyskocil | vyskoc001jos | 1904 | 15 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Martin Wachtel | 1904 | +5/27+ | Winnipeg Maroons | Northern League | , | ||
| Waddell | waddel001--- | 1904 | 7/2 | Sheffield | Tennessee-Alabama League | , | |
| Ernie Wade | wade--002ern | 1904 | Bridgeport Orators | Connecticut State League | , | ||
| Ham Wade | wade--001abr | 1904 | Pottstown PA | Independent | , | ||
| James Wadsworth | wadswo000jim | 1904 | Williams College | College | , | ||
| James Wadsworth | wadswo000jim | 1904 | 6/30-9/7 | Corning White Ponies | Southern Tier League | , | |
| Wagner | 1904 | 40 g. | Newark OH | Independent | , | ||
| Butts Wagner | wagner001but | 1904 | 4/30-8/22 | Providence Grays | Eastern League | , | |
| George Wagner | 1904 | Vicksburg Hill Billies | Cotton States League | , | |||
| Heinie Wagner | wagner001cha | 1904 | 4/29-8/6 | Newark Sailors | Eastern League | , | |
| Ivor Wagner | wagner001ivo | 1904 | Newark OH | , | |||
| Ivor Wagner | wagner001ivo | 1904 | 5/7-5/23+ | Waterloo Microbes | Iowa League | , | |
| Ivor Wagner | wagner001ivo | 1904 | +6/6-7/13 | Burlington River Rats | Iowa League | , | |
| Ivor Wagner | wagner001ivo | 1904 | +7/24- | 34 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , |
| Ivor Wagner | wagner001ivo | 1904 | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | ||
| Jay Wagner | wagner012--- | 1904 | 146 ab | Monroe Hill Citys | Cotton States League | , | |
| Jay Wagner | wagner012--- | 1904 | 9/19-9/22 | Shreveport Pirates | Southern Association | , | |
| John Wagner | wagner003joh | 1904 | , | ||||
| John Wagner | wagner003joh | 1904 | 34 g. | Rockford Red Sox | Illinois-Indiana-Iowa League | , | |
| John Wagner | wagner003joh | 1904 | Bloomington Bloomers | Illinois-Indiana-Iowa League | , | ||
| Louis Wagner | wagner001l-- | 1904 | 14+ g. | Cairo Champions | Kentucky-Illinois-Tennessee League | , | |
| Otto Wagner | wagner001ott | 1904 | 4/27-5/4 | Birmingham Barons | Southern Association | , | |
| Otto Wagner | wagner001ott | 1904 | 6/2-6/10 | Birmingham Barons | Southern Association | , | |
| Dit Wakefield | wakefi001hen | 1904 | 8 g. | Springfield Midgets | Missouri Valley League | , | |
| Dit Wakefield | wakefi001hen | 1904 | 6/3-8/1+ | Chattanooga | Tennessee-Alabama League | , | |
| H. J.? Wakefield | 1904 | 8/12 | Penn Yan Grape Pickers | Southern Tier League | , | ||
| Irv Waldron | waldro001irv | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| Walker | 1904 | 6/30 | Paris Parasites/Ardmore Territorians | Texas League | , | ||
| Ed Walker | walker001edw | 1904 | Coshocton OH | Independent | , | ||
| Mysterious Walker | walker004fre | 1904-05 | Univ. of Chicago | College | , | ||
| Otto Walker | 1904 | 4/27-5/4 | Birmingham Barons | Southern Association | , | ||
| Otto Walker | 1904 | 6/2-6/10 | Birmingham Barons | Southern Association | , | ||
| Tom Walker | walker006tho | 1904 | 24 g. | Cincinnati | National League | Cincinnati, OH | |
| Carl Wall | 1904 | Vicksburg Hill Billies | Cotton States League | , | |||
| Joe Wall | wall--005jos | 1904 | 4/29-5/26 | Rochester Bronchos | Eastern League | , | |
| Joe Wall | wall--005jos | 1904 | +6/12+ | Hoboken NJ | Independent | , | |
| Joe Wall | wall--005jos | 1904 | 9/4-9/30 | Harrisburg Senators | Tri-State League | , | |
| Arthur Wallace | wallac001art | 1904 | 12 g. | Jackson Senators | Delta League | , | |
| Arthur Wallace | wallac001art | 1904 | Biloxi MS | Independent | , | ||
| Harry Wallace | wallac003har | 1904 | 23 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Jim Wallace | wallac005jam | 1904 | 4/30-9/17 | Haverhill Hustlers | New England League | , | |
| Robert Wallace | wallac001rob | 1904 | Cairo Champions | Kentucky-Illinois-Tennessee League | , | ||
| Robert Wallace | wallac001rob | 1904 | 435 ab | Vicksburg Hill Billies | Cotton States League | , | |
| Red Waller | waller001joh | 1904 | Concord Marines | New England League | , | ||
| Red Waller | waller001joh | 1904 | 1 g. | Bridgeport Orators | Connecticut State League | , | |
| Red Waller | waller001joh | 1904 | Bayonne NJ | Independent | , | ||
| R. J. Wallis | 1904 | Houston Wanderers | South Texas League | , | |||
| Walsh | 1904 | 8/16-8/18 | Marion Oilworkers/Peoria Distillers | Central League | , | ||
| Walsh | walsh-070--- | 1904 | 19 g. | Terre Haute Hottentots | Central League | , | |
| Walsh | 1904 | 5/-5/ | Oskaloosa Quakers | Iowa League | , | ||
| Ed Walsh | walsh-002edw | 1904 | Chicago | American League | Chicago, IL | ||
| Pete Walsh | walsh-001pet | 1904 | 5/10-5/21 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Pete Walsh | walsh-001pet | 1904 | 7/9-8/2 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Pete Walsh | walsh-001pet | 1904 | 8/5-8/8 | Corsicana Oil Citys | Texas League | , | |
| Timothy Walsh | walsh-070--- | 1904 | 8/30 | Dayton Veterans | Central League | , | |
| Timothy Walsh | walsh-070--- | 1904 | 9/2-9/11 | Terre Haute Hottentots | Central League | , | |
| William Walsh | walsh-001wil | 1904 | 178 ab | Saugerties | Hudson River League | , | |
| Clyde Walters | walter001cly | 1904 | 56 g. | Brookhaven | Delta League | , | |
| Daniel Walters | walter003d-- | 1904 | 5/10-8/27 | Baltimore Orioles | Eastern League | , | |
| Daniel Walters | walter003d-- | 1904 | 9/2-9/21 | Rochester Bronchos | Eastern League | , | |
| Henry Walters | walter001hen | 1904 | 120 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| Jack Walters | walter001joh | 1904 | San Jose | California State League | , | ||
| Jack Walters | walter001joh | 1904 | 4/29-9/28 | Montreal Royals | Eastern League | , | |
| Lew Walters | walter001lew | 1904 | 4/23-9/24 | Memphis Egyptians | Southern Association | , | |
| Roxey Walters | walter001lou | 1904 | 120 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| Jack Wanner | wanner001cla | 1904 | Rock Island Islanders | Illinois-Indiana-Iowa League | , | ||
| Ward | ward--017--- | 1904 | 8 ab | Monroe Hill Citys | Cotton States League | , | |
| Harry Ward | 1904 | 7/5-7/19 | Sioux City Soos | Western League | , | ||
| James Ward | 1904 | +6/16+ | Umpire | Pacific National League | , | ||
| Piggy Ward | ward--002fra | 1904 | 90 g. | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Piggy Ward | ward--002fra | 1904 | 8/23-9/24 | Birmingham Barons | Southern Association | , | |
| Rube Ward | ward--003joh | 1904 | 18 g. | Boise Fruit Pickers | Pacific National League | , | |
| Rube Ward | ward--003joh | 1904 | Salt Lake City Elders | Pacific National League | , | ||
| Warner | 1904 | 11 g. | Rock Island Islanders | Illinois-Indiana-Iowa League | , | ||
| Andrew Warner | warner001and | 1904 | +5/21-9/24+ | Oklahoma City Mets | Southwestern League | , | |
| Bobby Warner | warner002rob | 1904 | 5/7-9/5 | Marshalltown Grays | Iowa League | , | |
| Charles Warner | warner014--- | 1904 | +6/9-7/ | Sheffield | Tennessee-Alabama League | , | |
| Homer Warner | warner001hom | 1904 | +8/16+ | Sault Ste. Marie | Independent | , | |
| Jack Warner | warner002joh | 1904 | 86 g. | New York | National League | New York, NY | |
| James Warner | 1904 | Univ. Illinois | College | , | |||
| Warr'l | warrl-000--- | 1904 | 7/11 | Wilmington Peaches | Tri-State League | , | |
| Wally Warren | warren002wal | 1904 | 4/30- | Fall River Indians | New England League | , | |
| Wally Warren | warren002wal | 1904 | -9/17 | Manchester | New England League | , | |
| Mum Warrender | warren002fra | 1904 | 4/28-9/11 | Terre Haute Hottentots | Central League | , | |
| Buck Washer | washer001wil | 1904 | WC-Brandywine | Independent | , | ||
| William Wasson | 1904 | Northwestern U. | College | , | |||
| William Wasson | 1904-06 | Univ. of Illinois | College | , | |||
| Frank Waterbury | waterb001fra | 1904 | Los Angeles Angels | Pacific Coast League | , | ||
| William Waterman | waterm001wil | 1904 | 5/6-9/17 | Troy Trojans | New York State League | , | |
| Bill Watkins | watkin002bil | 1904 | 4/20-9/20 | Minneapolis Millers | American Association | , | |
| Scott Watson | 1904-06 | Tufts University | College | , | |||
| Scott Watson | 1904 | Reading CA | Independent | , | |||
| Watt | watt--001--- | 1904 | Chester | Pennsylvania League | , | ||
| Watt | 1904 | 9 g. | Sharon OH | Independent | , | ||
| George Watt | watt--001geo | 1904 | 4/27-9/24 | Little Rock Travelers | Southern Association | , | |
| Adolph Wattrick | wattri001e-- | 1904 | +5/29-8/21 | Petoskey MI | Independent | , | |
| Al Watts | watts-001al- | 1904 | , | ||||
| Oscar Way | way---001osc | 1904 | U. of Indiana | College | , | ||
| Henry Weakley | weakle001hen | 1904 | 38+ g. | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | |
| Dick Weand | weand-001geo | 1904 | Pottstown | Pennsylvania League | , | ||
| Weaver | 1904 | -5/27 | Vanderbilt Univ. | College | , | ||
| Weaver | weaver001w-- | 1904 | 3 g. | Decatur | Tennessee-Alabama League | , | |
| Art Weaver | weaver001art | 1904 | 4/29-9/20 | Minneapolis Millers | American Association | , | |
| Farmer Weaver | weaver001far | 1904 | 129 g. | Boise Fruit Pickers | Pacific National League | , | |
| John Weaver | weaver003joh | 1904 | 5/6-8/3 | Utica Pent-Ups | New York State League | , | |
| John Weaver | weaver003joh | 1904 | 8/6-9/17 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Thomas Weaver | weaver001tho | 1904 | 9 g. | Bessemer | Tennessee-Alabama League | , | |
| Thomas Weaver | weaver001tho | 1904 | +6/17+ | Decatur | Tennessee-Alabama League | , | |
| W. Weaver | weaver001w-- | 1904 | 5/16-5/24+ | Sheffield | Tennessee-Alabama League | , | |
| W. Weaver | weaver001w-- | 1904 | +6/1-6/23+ | Bessemer | Tennessee-Alabama League | , | |
| W. Weaver | weaver001w-- | 1904 | 2 g. | Decatur | Tennessee-Alabama League | , | |
| Webb | webb--037--- | 1904 | 6/30-8/16+ | Hornellsville Maple Cities | Southern Tier League | , | |
| Cleon Webb | 1904-08 | Ohio Wesleyan | College | , | |||
| Arthur Weber | weber-001art | 1904 | -9/2 | 47 g. | Houston Wanderers | South Texas League | , |
| Charlie Weber | weber-003cha | 1904 | 13 g. | Beaumont Millionaires | South Texas League | , | |
| Edward Webster | webste001edw | 1904 | 4/24-9/25 | St. Joseph Saints | Western League | , | |
| Al Weddige | weddig001alb | 1904 | 4/30-9/19 | Fall River Indians | New England League | , | |
| Fred Weed | weed--001fre | 1904 | Portland Browns | Pacific Coast League | , | ||
| Fred Weed | weed--001fre | 1904 | 97 g. | Salt Lake City Elders | Pacific National League | , | |
| Bert Weeden | weeden001cha | 1904 | Lynn MA | Independent | , | ||
| Samuel Weems | 1904-06 | Auburn Univ. | College | , | |||
| William Weida | weida-000wil | 1904 | +6/25+ | Cant.-Hampton | Independent | , | |
| Genser Weidensaul | weiden001yen | 1904 | 4/30-9/28 | Toronto Maple Leafs | Eastern League | , | |
| Bill Weigand | weigan002wil | 1904 | 27 g. | Decatur Commodores | Illinois-Indiana-Iowa League | , | |
| Curt Weigand | weigan001cur | 1904 | 5/11-91/0 | Williamsport Millionaires | Tri-State League | , | |
| Frank Weikart | weiker001fra | 1904 | 4/23-8/30 | Shreveport Pirates | Southern Association | , | |
| Frank Weikart | weiker001fra | 1904 | 9/9-9/25 | New Orleans Pelicans | Southern Association | , | |
| Weiland | weilan002--- | 1904 | +5/11+ | Emporia State | College | , | |
| Weiland | weilan002--- | 1904 | +8/11+ | Emporia KS | Independent | , | |
| Jake Weimer | weimer001jac | 1904 | 119 g. | Chicago | National League | Chicago, IL | |
| Louis Weisbecker | weisbe001lou | 1904 | Meriden Silverites | Connecticut State League | , | ||
| Raymond Weisbrod | weisbr001j-- | 1904 | +6/22-8/31+ | Keokuk Indians | Iowa League | , | |
| Raymond Weisbrod | weisbr001j-- | 1904 | +5/20+ | Grinnell College | College | , | |
| Raymond Weisbrod | weisbr001j-- | 1904 | +6/22-8/31+ | Keokuk Indians | Iowa League | , | |
| Cecil Weisenberger | weisen001cec | 1904 | Mt. Carmel PA | Independent | , | ||
| Jesse Weisinger | 1904 | 5/14- | Guthrie Blues | Southwestern League | , | ||
| Charles Weisner | weisne002cha | 1904 | Springfield Midgets | Missouri Valley League | , | ||
| Welch | welch-052--- | 1904 | 6/26-6/28 | Sioux City Soos | Western League | , | |
| Welch | welch-052--- | 1904 | 7/12- | Marshalltown Grays | Iowa League | , | |
| Welch | 1904 | 7/18-7/20 | Paris Parasites/Ardmore Territorians | Texas League | , | ||
| Conrad Welch | welch-001con | 1904 | 43 g. | Savannah Pathfinders | South Atlantic League | , | |
| Conrad Welch | welch-001con | 1904 | 9/14-9/24 | Montgomery Senators | Southern Association | , | |
| H. F. Welch | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | |||
| Harry Welch | welch-002har | 1904 | 4/24-9/25 | Omaha Rangers | Western League | , | |
| Harry Welch | welch-001har | 1904 | 5/6-6/27 | Binghamton Bingoes | New York State League | , | |
| Harry Welch | welch-001har | 1904 | 7/9-7/23 | Ilion Typewriters | New York State League | , | |
| Joseph Welch | welch-001jos | 1904 | 164 ab | Paterson Intruders | Hudson River League | , | |
| Kelly? Welch | welch-019--- | 1904 | +6/6-7/8+ | Burlington River Rats | Iowa League | , | |
| Thomas Welch/Welsh | 1904 | no g. | Saugerties | Hudson River League | , | ||
| Mike Welday | welday001lyn | 1904 | 92 g. | Joplin Miners | Missouri Valley League | , | |
| Burns Weller | weller001h-- | 1904 | Genesco NY | Independent | , | ||
| Wells | wells-034--- | 1904 | 6/5 | Roseburg Shamrocks | Oregon State League | , | |
| Wells | wells-011--- | 1904 | +6/11- | 31 g. | Superior Longshoremen | Northern League | , |
| Dummy Wells | 1904-05 | Princeton Univ. | College | , | |||
| Dummy Wells | 1904-05 | +7/4-8/17+ | Plattsburgh | Vermont League | , | ||
| John Welsh | 1904 | Pitt.-Collegians | Independent | , | |||
| John Welter | welter002joh | 1904 | 5/15-8/2 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Fred Wenig | wenig-001fre | 1904 | 5/2-6/10 | Newark Sailors | Eastern League | , | |
| Fred Wenig | wenig-001fre | 1904 | 6/19-8/18 | Toledo Mud Hens | American Association | , | |
| Jack Wentz | wentz-001jac | 1904 | 5/21-5/25 | Evansville River Rats | Central League | , | |
| Jack Wentz | wentz-001jac | 1904 | 33 g. | Hattiesburg | Delta League | , | |
| Perry Werden | werden001per | 1904 | 5/19-7/ | Fargo | Northern League | , | |
| William Wernecke | 1904 | 52 g. | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | ||
| George Werner | werner002geo | 1904 | +6/2-8/12+ | Calumet Aristocrats | Copper Country League | , | |
| Red Werner | 1904 | Oklahoma City Mets | Southwestern League | , | |||
| Red Werner | 1904 | Guthrie Blues | Southwestern League | , | |||
| William Wesp | wesp--000--- | 1904 | Coshocton OH | Independent | , | ||
| Frank Wessel | wessel002fra | 1904 | Piqua OH | Independent | , | ||
| Frank Wessel | wessel002fra | 1904 | 7/28-9/12 | Wheeling Stogies | Central League | , | |
| George Wessler | wessle001geo | 1904 | Ogden-Wessler | Independent | , | ||
| George Wessler | wessle001geo | 1904 | -7/ | Ogden UT | Independent | , | |
| Tommy? West | west--032--- | 1904 | 5/8 | Hoquiam Perfect Gentlemen | Southwest Washington League | , | |
| Ralph Westcott | westco001ral | 1904 | 4/29 | Sioux City Soos | Western League | , | |
| Oscar Westerberg | wester001osc | 1904-08 | St. Mary’s Col. | College | , | ||
| Oscar Westerberg | wester001osc | 1904 | Stockton | California State League | , | ||
| Westervelt | wester004--- | 1904 | 9/10 | Corning White Ponies | Southern Tier League | , | |
| Bob Westlake | westla001rob | 1904 | 4/27-5/12 | Corsicana Oil Citys | Texas League | , | |
| Bob Westlake | westla001rob | 1904 | +6/3+ | Umpire | Texas League | , | |
| Bob Westlake | westla001rob | 1904 | 7/1-7/13 | Corsicana Oil Citys | Texas League | , | |
| Bob Westlake | westla001rob | 1904 | 8/16-9/4 | Wheeling Stogies | Central League | , | |
| George Westlake | westla002geo | 1904 | 77 g. | Houston Wanderers | South Texas League | , | |
| James Westlake | westla001jam | 1904 | Paterson Intruders | Hudson River League | , | ||
| James Westlake | westla001jam | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| W. Westlake | 1904 | 9/2 | Wheeling Stogies | Central League | , | ||
| Gus Weyhing | weyhin001aug | 1904 | Umpire | American Association | , | ||
| Whalen | whalen017--- | 1904 | Mt. Clements MI | Independent | , | ||
| Henry Whalen | whalen000hen | 1904 | 5/6 | Terre Haute Hottentots | Central League | , | |
| Jimmy Whalen | whalen003wil | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| Charles Wheeler | wheele004cha | 1904 | 5/16-8/2+ | Chattanooga | Tennessee-Alabama League | , | |
| Ed Wheeler | wheele003edw | 1904 | 4/20-9/20 | St. Paul Saints | American Association | , | |
| George Wheeler | wheele002geo | 1904 | Los Angeles Angels | Pacific Coast League | , | ||
| George Wheeler | wheele002geo | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| Eugene Whipple | whippl001eug | 1904 | 34 g. | Macon Highlanders | South Atlantic League | , | |
| Eugene Whipple | whippl001eug | 1904 | Augusta Tourists | South Atlantic League | , | ||
| George Whisner | whisne001geo | 1904 | 34 g. | Warren OH | Independent | , | |
| Lew Whistler | whistl002lew | 1904 | 4/23-6/17 | Memphis Egyptians | Southern Association | , | |
| John Whitaker | whitak001j-- | 1904 | 5/16-8/20 | Chattanooga | Tennessee-Alabama League | , | |
| L. H. Whitaker | 1904 | Oneida or Fulton | Empire League | , | |||
| White | white-015--- | 1904 | +6/20-8/2+ | Columbia | Tennessee-Alabama League | , | |
| Carl White | white-001car | 1904 | 8/5-8/15 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Dan White | 1904 | 5/7- | 6 g. | Boone Coal Miners | Iowa League | , | |
| Frank White | white-005--- | 1904 | 15 g. | Topeka Saints | Missouri Valley League | , | |
| George White | white-006geo | 1904 | 4/28-5/28 | Eugene Blues | Oregon State League | , | |
| George White | white-006geo | 1904 | 5/29-7/4 | Roseburg Shamrocks | Oregon State League | , | |
| Harry White | white-009har | 1904 | Louisville Colonels | American Association | , | ||
| Harry White | white-009har | 1904 | 8/10-9/25 | Denver Grizzlies | Western League | , | |
| Harvey White | 1904 | +4/24-10/13+ | Muskegon MI | Independent | , | ||
| J. W. White | white-004j-- | 1904 | 5/16-8/3 | Knoxville | Tennessee-Alabama League | , | |
| J. W. White | white-004j-- | 1904 | 8/4- | Brevard | Carolina Interstate League | , | |
| Jack White | white-012joh | 1904 | 4/29-9/28 | Toronto Maple Leafs | Eastern League | , | |
| Jack White | white-012joh | 1904 | 6/26 | Boston | National League | Boston, MA | |
| Robert White | white-010rob | 1904 | 4/26-7/18 | Shreveport Pirates | Southern Association | , | |
| Robert White | white-010rob | 1904 | Pine Bluff Lumbermen | Cotton States League | , | ||
| William White | white-024wil | 1904 | 148 g. | Sedalia Goldbugs | Missouri Valley League | , | |
| William White | white-005w-- | 1904 | +5/24- | 23 g. | Fargo | Northern League | , |
| William White | white-005w-- | 1904 | Lisbon ND | Independent | , | ||
| William White | white-005w-- | 1904 | +7/25-8/13 | Fargo | Northern League | , | |
| R. W. Whitehead | whiteh001r-- | 1904 | Sheffield | Tennessee-Alabama League | , | ||
| R. W. Whitehead | whiteh001r-- | 1904 | Hopkinsville Browns | Kentucky-Illinois-Tennessee League | , | ||
| Jesse Whiting | whitin002jes | 1904 | Manchester | New England League | , | ||
| James Whitley | whitle001jam | 1904 | 7 g. | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | |
| James Whitley | whitle001jam | 1904 | no g. | New York | American League | New York, NY | |
| Herbert Whitney | whitle001her | 1904 | Calgary | , | |||
| Merle Whitney | whitne001mer | 1904 | 6/29-9/9 | Addison White Sox | Southern Tier League | , | |
| Merle Whitney | whitne001mer | 1904 | 7/21- | Kent OH | Independent | , | |
| Al Whitridge | whitri001alb | 1904 | 3/30-5/15 | Oakland Oaks | Pacific Coast League | , | |
| Al Whitridge | whitri001alb | 1904 | 5/29-6/29 | Oakland | California State League | , | |
| Al Whitridge | whitri001alb | 1904 | 7/7-9/25 | New Orleans Pelicans | Southern Association | , | |
| Charles Whitten | whitte006--- | 1904 | 6 g. | Bessemer | Tennessee-Alabama League | , | |
| Charles Whitten | whitte005--- | 1904 | &/15-8/2+ | Chattanooga | Tennessee-Alabama League | , | |
| Bob Wicker | wicker001rob | 1904 | 50 g. | Chicago | National League | Chicago, IL | |
| Edward Wicker | wicker001edw | 1904 | Baylor Univ | College | , | ||
| Edward Wicker | wicker001edw | 1904 | 6/18 | Corsicana Oil Citys | Texas League | , | |
| Wiernels | 1904 | Illinois-Indiana-Iowa League | , | ||||
| Wiernels | 1904 | Sedalia Goldbugs | Missouri Valley League | , | |||
| Freeman Wiggin | wiggin000fre | 1904 | Holyoke Paperweights | Connecticut State League | , | ||
| Jimmy Wiggs | wiggs-001jam | 1904 | 13 g. | Salt Lake City Elders | Pacific National League | , | |
| Jimmy Wiggs | wiggs-001jam | 1904 | 6/26-9/24 | New Orleans Pelicans | Southern Association | , | |
| Shanks Wilbur | wilbur000sha | 1904 | 35 g. | Lancaster PA | Independent | , | |
| Shanks Wilbur | wilbur000sha | 1904 | Coatesville PA | Independent | , | ||
| Shanks Wilbur | wilbur000sha | 1904 | 7/27-9/10 | Elmira | Southern Tier League | , | |
| Edwin Wilder | wilder015--- | 1904 | 5/20- | Nashua | New England League | , | |
| Edwin Wilder | wilder015--- | 1904 | -7/28 | Manchester | New England League | , | |
| Percy Wilder | wilder001per | 1904 | 25+ g. | Cairo Champions | Kentucky-Illinois-Tennessee League | , | |
| Jack Wiley | wiley-001joh | 1904 | 4/30- | Haverhill Hustlers | New England League | , | |
| Jack Wiley | wiley-001joh | 1904 | -9/17 | Lawrence Colts | New England League | , | |
| Harry Wilhelm | wilhel002har | 1904 | Kingston Colonials | Hudson River League | , | ||
| Irvin Wilhelm | wilhel001irv | 1904 | 39 g. | Boston | National League | Boston, MA | |
| Joseph Wilkes | wilkes001jos | 1904 | 6/7- | Duluth White Sox | Northern League | , | |
| Joseph Wilkes | wilkes001jos | 1904 | 51 g. | Superior Longshoremen | Northern League | , | |
| Joseph Wilkes | wilkes001jos | 1904 | +8/16-9/1+ | Portage Lake | Copper Country League | , | |
| Glen Wilkins | wilkin000gle | 1904 | +4/10+ | Chelias WA | Independent | , | |
| Glen Wilkins | wilkin000gle | 1904 | 5/20-5/30 | Salem Raglands | Oregon State League | , | |
| Joe Wilkins | wilkin001jos | 1904 | +4/10+ | Chelais WA | Independent | , | |
| Joe Wilkins | wilkin001jos | 1904 | 4/29-7/4 | Salem Raglands | Oregon State League | , | |
| Joe Wilkins | wilkin001jos | 1904 | 7/24-8/21 | Centralia Midgets | Southwest Washington League | , | |
| Joe Wilkins | wilkin001jos | 1904 | 9/4 | Aberdeen Pippins | Southwest Washington League | , | |
| Roy Wilkins | wilkin001roy | 1904 | , | ||||
| Wilkinson | 1904 | Dayton Veterans | Central League | , | |||
| Wilkinson | 1904 | Grand Rapids Orphans | Central League | , | |||
| Wilkinson | 1904 | 5/6- | 2 g. | Oskaloosa Quakers | Iowa League | , | |
| Wilkinson | wilkin007--- | 1904 | 8/17 | Sheffield | Tennessee-Alabama League | , | |
| Wilkinson | wilkin024--- | 1904 | 6/29-8/12 | Penn Yan Grape Pickers | Southern Tier League | , | |
| George Wilkinson | wilkin003geo | 1904 | 5/28-6/8 | Evansville River Rats | Central League | , | |
| George Wilkinson | wilkin003geo | 1904 | 31+ g. | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | |
| Jack Wilkinson | wilkin004jac | 1904 | 5/29- | San Antonio Bronchos | South Texas League | , | |
| Jack Wilkinson | wilkin004jac | 1904 | -6/10 | Houston Wanderers | South Texas League | , | |
| William Wilkinson | wilkin003geo | 1904 | +5/29+ | Evansville River Rats | Central League | , | |
| W. E. Willette | willet003--- | 1904 | 65 g. | Canton | Delta League | , | |
| W. E. Willette | willet003--- | 1904 | Yazoo City Zoos | Delta League | , | ||
| Williams | willia333--- | 1904 | 5/8-7/24 | Centralia Midgets | Southwest Washington League | , | |
| Williams | willia309--- | 1904 | 7/9-7/13 | Manchester | New England League | , | |
| Williams | willia266--- | 1904 | Henderson Blue Birds | Kentucky-Illinois-Tennessee League | , | ||
| Williams | willia266--- | 1904 | 47 ab | Natchez Indians | Cotton States League | , | |
| Williams | willia261--- | 1904 | 48 g. | Brookhaven | Delta League | , | |
| Alfred Williams | willia001alf | 1904 | Poughkeepsie Colts | Hudson River League | , | ||
| Clyde Williams | willia002s-- | 1904 | 5/7-9/5 | Marshalltown Grays | Iowa League | , | |
| Dal Williams | willia001lev | 1904 | 97 g. | Davenport River Rats | Illinois-Indiana-Iowa League | , | |
| Dave Williams | willia013dav | 1904 | 5/11-8/13+ | Altoona Mountaineers | Tri-State League | , | |
| Jimmy Williams | willia025jam | 1904 | New York | American League | New York, NY | ||
| Nick Williams | willia011ric | 1904 | Santa Clara U. | College | , | ||
| Nick Williams | willia011ric | 1904 | 74 g. | Seattle Siwashes | Pacific Coast League | , | |
| O. N. Williams | willia002o-- | 1904 | Rock Island Islanders | Illinois-Indiana-Iowa League | , | ||
| O. N. Williams | willia002o-- | 1904 | 5 g. | Little Rock Travelers | Southern Association | , | |
| Otto Williams | willia001ott | 1904 | 57 g. | Chicago | National League | Chicago, IL | |
| Tom Williams | willia004tom | 1904 | 4/20-5/28 | Indianapolis Indians | American Association | , | |
| Tom Williams | willia004tom | 1904 | 6/12-9/5 | Evansville River Rats | Central League | , | |
| W. Williams | willia005w-- | 1904 | 5/12-7/4 | Salem Raglands | Oregon State League | , | |
| Williamson | willia002w-- | 1904 | +6/20-8/10 | Columbia | Tennessee-Alabama League | , | |
| W. N. Williamson | willia002w-- | 1904 | 5/16-8/17 | Knoxville | Tennessee-Alabama League | , | |
| Henry Willig | willig001hen | 1904 | 402 ab | Monroe Hill Citys | Cotton States League | , | |
| Louie Willig | willig001lou | 1904 | 5/4-5/6 | Rochester Bronchos | Eastern League | , | |
| Louie Willig | willig001lou | 1904 | 5/12-9/17 | Binghamton Bingoes | New York State League | , | |
| Willingham | 1904 | 6/25,7/17 | Dallas Giants | Texas League | , | ||
| Willingham | 1904 | +9/3+ | Dallas-Eagles | Amateur | , | ||
| Willis | 1904 | +7/19-7/22+ | Oskaloosa Quakers | Iowa League | , | ||
| Delaware Willis | willis001del | 1904 | 6/3-7/16 | Nashville Volunteers | Southern Association | , | |
| Delaware Willis | willis001del | 1904 | Clarksville Grays | Kentucky-Illinois-Tennessee League | , | ||
| Ralph Willis | willis001ral | 1904 | 7/30 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Ralph Willis | willis001ral | 1904 | Urbana OH | Independent | , | ||
| Ralph Willis | willis001ral | 1904 | 8/4-9/8 | Marion Oilworkers/Peoria Distillers | Central League | , | |
| Vic Willis | willis001vic | 1904 | Boston | National League | Boston, MA | ||
| Robert Willner | willne001rob | 1904 | 4/29-5/1 | Salem Raglands | Oregon State League | , | |
| Robert Willner | willne001rob | 1904 | 7/31-9/4 | Aberdeen Pippins | Southwest Washington League | , | |
| Charles Wills | wills-001cha | 1904 | 4/17-8/15 | Fort Worth Panthers | Texas League | , | |
| Albert Wilmot | wilmot001alb | 1904 | no g. | Grand Rapids Orphans | Central League | , | |
| Albert Wilmot | wilmot001alb | 1904 | 22 g. | Mount Vernon OH | Independent | , | |
| Albert Wilmot | wilmot001alb | 1904 | Canton OH | Independent | , | ||
| Walt Wilmot | wilmot001wal | 1904 | 4/30-9/25 | Butte Miners/Fruit Pickers | Pacific National League | , | |
| Robert Wilner | willne001rob | 1904 | Aberdeen Pippins | Southwest Washington League | , | ||
| Wilson | 1904 | 5/2-5/5 | San Antonio Bronchos | South Texas League | , | ||
| Wilson | 1904 | 8 g. | Vincennes Reds | Kentucky-Illinois-Tennessee League | , | ||
| Wilson | 1904 | +8/8-8/17+ | Umpire | New York State League | , | ||
| Wilson | 1904 | 6/30 | Corsicana Oil Citys | Texas League | , | ||
| Wilson | 1904 | 5/24-5/25+ | Knoxville | Tennessee-Alabama League | , | ||
| Wilson | 1904 | +6/7+ | Bessemer | Tennessee-Alabama League | , | ||
| Artie Wilson | wilson005art | 1904 | 121 g. | Iola Gasbags | Missouri Valley League | , | |
| Bill Wilson | wilson003bil | 1904 | 6/17 | Toledo Mud Hens | American Association | , | |
| Bill Wilson | wilson003bil | 1904 | 7/5-7/30+ | Winnipeg Maroons | Northern League | , | |
| Christy Wilson | wilson003chr | 1904 | RoIsl-Independents | Amateur | , | ||
| Christy Wilson | wilson003chr | 1904 | 9/8- | Rock Island Islanders | Illinois-Indiana-Iowa League | , | |
| Eugene Wilson | 1904 | 5/2 | Dayton Veterans | Central League | , | ||
| Gary Wilson | wilson010jam | 1904 | 4/30-9/17 | Nashua | New England League | , | |
| Harry Wilson | wilson003hen | 1904 | 4/30- | New Bedford Whalers | New England League | , | |
| Harry Wilson | wilson003hen | 1904 | -7/6 | Nashua | New England League | , | |
| Howard Wilson | wilson001how | 1904 | Washington | American League | Washington, DC | ||
| Jasper Wilson | wilson020jam | 1904 | no g. | Columbia | , | ||
| Jasper Wilson | wilson020jam | 1904 | 111 g. | Charleston Sea Gulls | South Atlantic League | , | |
| Jasper Wilson | wilson020jam | 1904 | Augusta Tourists | South Atlantic League | , | ||
| Jesse Wilson | wilson004jes | 1904 | Cripple Creek | Independent | , | ||
| Jesse Wilson | wilson004jes | 1904 | 8/30 | Colorado Springs Millionaires | Western League | , | |
| Jesse Wilson | wilson004jes | 1904 | Stockton | California State League | , | ||
| Parke Wilson | wilson001par | 1904 | Seattle Siwashes | Pacific Coast League | , | ||
| Parke Wilson | wilson001par | 1904 | San Francisco Seals | Pacific Coast League | , | ||
| S. A. Wilson | wilson002s-- | 1904 | 4/30-5/15 | San Antonio Bronchos | South Texas League | , | |
| S. A. Wilson | wilson002s-- | 1904 | 5/17-6/30 | Beaumont Millionaires | South Texas League | , | |
| Willis Wilson | wilson025wil | 1904 | 5/7-9/5 | Marshalltown Grays | Iowa League | , | |
| Zeke Wilson | wilson002zek | 1904 | 6/4-8/31 | Montgomery Senators | Southern Association | , | |
| Hooks Wiltse | wiltse001geo | 1904 | New York | National League | New York, NY | ||
| Lewis Wiltse | wiltse001lew | 1904 | 4/29-9/28 | Baltimore Orioles | Eastern League | , | |
| W. Harlan Wingard | wingar001har | 1904 | Augusta Tourists | South Atlantic League | , | ||
| Lave Winham | winham001laf | 1904 | 5/13 Exh | Wilmington Peaches | Tri-State League | , | |
| Big Liz Winston | winsto001--- | 1904 | +10/8 | Rich.-Brownies | Twin City League | , | |
| Dicey Winston | winsto006--- | 1904 | U. North Carolina | College | , | ||
| Dicey Winston | winsto006--- | 1904 | +6/20+ | Wake Forest NC | Independent | , | |
| George Winter | winter001geo | 1904 | Boston | American League | Boston, MA | ||
| George Winters | 1904 | 7/24- | Camden NJ | Independent | , | ||
| George Winters | winter002geo | 1904 | 6/27-9/24 | Atlanta Crackers | Southern Association | , | |
| Morgan Winters | 1904 | East Liverpool | Independent | , | |||
| Scott Winters | winter002sco | 1904 | no g. | Atlanta Crackers | Southern Association | , | |
| Scott Winters | winter002sco | 1904 | 6/16-6/18 | Nashville Volunteers | Southern Association | , | |
| Scott Winters | winter002sco | 1904 | 7/7 | Atlanta Crackers | Southern Association | , | |
| Scott Winters | winter002sco | 1904 | 8/7-9/20 | Atlanta Crackers | Southern Association | , | |
| Pat Wise | wise--001ler | 1904 | Lima OH | Independent | , | ||
| Doc Wiseman | wisema001jul | 1904 | 4/21-9/24 | Nashville Volunteers | Southern Association | , | |
| Gus Wisser | wisser001a-- | 1904 | 8/25-9/15 | St. Joseph Saints | Western League | , | |
| George Witbeck | witbec001geo | 1904 | 5/7-5/14 | Birmingham Barons | Southern Association | , | |
| George Witbeck | witbec001geo | 1904 | 7/5-7/15 | Winnipeg Maroons | Northern League | , | |
| Harvey Witt | witt--002har | 1904 | Rockford Red Sox | Illinois-Indiana-Iowa League | , | ||
| Harvey Witt | witt--002har | 1904 | +5/29+ | Portage Lake | Copper Country League | , | |
| Harvey Witt | witt--002har | 1904 | 5/19-5/31 | Crookston Crooks | Northern League | , | |
| Harvey Witt | witt--002har | 1904 | Bemidji MN | Independent | , | ||
| Harvey Witt | witt--002har | 1904 | 9/20 | Kansas City Blues | American Association | , | |
| Barney Wolfe | wolfe-001wil | 1904 | 7 g. | New York | American League | New York, NY | |
| Barney Wolfe | wolfe-001wil | 1904 | 17 g. | Washington | American League | Washington, DC | |
| Maurice Wolfe | wolfe-001mau | 1904 | 5/7-5/22 | Toronto Maple Leafs | Eastern League | , | |
| Maurice Wolfe | wolfe-001mau | 1904 | 5/31-6/8 | Newark Sailors | Eastern League | , | |
| Maurice Wolfe | wolfe-001mau | 1904 | 7/22-9/22 | Newark Sailors | Eastern League | , | |
| Orville Wolfe | 1904 | Mt. Carmel IL | Independent | , | |||
| Roland Wolfe | wolfe-001rol | 1904 | 4/29-6/8 | Milwaukee Brewers | American Association | , | |
| Roland Wolfe | wolfe-001rol | 1904 | 89 g. | Dubuque Shamrocks | Illinois-Indiana-Iowa League | , | |
| Roland Wolfe | wolfe-001rol | 1904 | 9/14-9/20 | Milwaukee Brewers | American Association | , | |
| Harry Wolverton | wolver001har | 1904 | 102 g. | Philadelphia | National League | Philadelphia, PA | |
| Womack | 1904 | +5/11+ | Waterloo Microbes | Iowa League | , | ||
| John Womack | womack001har | 1904 | Oklahoma City Mets | Southwestern League | , | ||
| Louis Womble | womble001lou | 1904 | 10 g. | Jacksonville Jays | South Atlantic League | , | |
| Louis Womble | womble001lou | 1904 | 5/18-6/4+ | Bessemer | Tennessee-Alabama League | , | |
| Louis Womble | womble001lou | 1904 | +6/16-8/20 | Huntsville | Tennessee-Alabama League | , | |
| Louis Womble | womble001lou | 1904 | Knoxville TN | Independent | , | ||
| Louis Womble | womble001lou | 1904 | 9/7-9/25 | Montgomery Senators | Southern Association | , | |
| Bob Wood | wood--005rob | 1904 | 49 g. | Detroit | American League | Detroit, MI | |
| Carl Wood | wood--001car | 1904 | 119 g. | Springfield Midgets | Missouri Valley League | , | |
| George Wood | wood--004geo | 1904 | 4/21-9/25 | Umpire | Southern Association | , | |
| Harry Wood | wood--001har | 1904 | 5/19-6/25 | Winnipeg Maroons | Northern League | , | |
| M. J. Wood | 1904 | 7/15 | Grand Rapids Orphans | Central League | , | ||
| Roy Woodbury | woodbu001roy | 1904 | Leavenworth Orioles | Missouri Valley League | , | ||
| Woodruff | woodru003--- | 1904 | +5/24+ | Sheffield | Tennessee-Alabama League | , | |
| Guy Woodruff | woodru001guy | 1904 | 299 ab | Baton Rouge Red Sticks | Cotton States League | , | |
| Sam Woodruff | woodru001orv | 1904 | Cincinnati | National League | Cincinnati, OH | ||
| Walt Woods | woods-002wal | 1904 | 4/29-9/26 | Jersey City Skeeters | Eastern League | , | |
| Woodyatt | 1904 | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |||
| Frank Wooliver | wooliv001fra | 1904 | 18 g. | Leavenworth Orioles | Missouri Valley League | , | |
| C. Woolridge | woolri000c-- | 1904 | 5/9 | Colorado Springs Millionaires | Western League | , | |
| Lloyd Wooten | wooten000llo | 1904 | +4/1+ | Trinity College | College | , | |
| Workman | workma002cla | 1904 | 9/7 | Rochester Bronchos | Eastern League | , | |
| Worthington | worthi005--- | 1904 | 8/16,9/19 | Rochester Bronchos | Eastern League | , | |
| John Wratten | wratte001irv | 1904 | +7/8+ | Zanesville OH | ProtAssn | , | |
| Samuel Wray | 1904 | Denton AC TX | Independent | , | |||
| Wright | 1904 | +8/11+ | Oskaloosa Quakers | Iowa League | , | ||
| Forrest Wright | wright001for | 1904 | 4/22-7/25 | Louisville Colonels | American Association | , | |
| Gene Wright | wright001cla | 1904 | 4/18 | St. Louis | American League | St. Louis, MO | |
| Gene Wright | wright001cla | 1904 | 5/15-7/13 | Boise Fruit Pickers | Pacific National League | , | |
| Gene Wright | wright001cla | 1904 | 7/29-9/23 | Atlanta Crackers | Southern Association | , | |
| Lucky Wright | wright007wil | 1904 | 7/9-7/30 | San Antonio Bronchos | South Texas League | , | |
| Lucky Wright | wright007wil | 1904 | 8/9 | Galveston Sand Crabs | South Texas League | , | |
| Lucky Wright | wright015wil | 1904 | Decatur Commodores | Illinois-Indiana-Iowa League | , | ||
| Lucky Wright | wright015wil | 1904 | 7/9-7/30 | San Antonio Bronchos | South Texas League | , | |
| Lucky Wright | wright015wil | 1904 | 8/9 | Galveston Sand Crabs | South Texas League | , | |
| Pat Wright | wright003pat | 1904 | 4/23-9/24 | Little Rock Travelers | Southern Association | , | |
| Red Wright | wright001jos | 1904 | 84 g. | Springfield Hustlers | Illinois-Indiana-Iowa League | , | |
| Zeke Wrigley | wrigle001zek | 1904 | 4/20-9/20 | Columbus Senators | American Association | , | |
| Wyatt | wyatt-009--- | 1904 | 8/3 | Sheffield | Tennessee-Alabama League | , | |
| Hugh Wyatt | wyatt-006--- | 1904 | Huntingdon TN | Independent | , | ||
| Hugh Wyatt | wyatt-006--- | 1904 | +8/2-8/19 | Chattanooga | Tennessee-Alabama League | , | |
| Hugh Wyatt | wyatt-006--- | 1904 | +9/3+ | Johnsonville TN | Independent | , | |
| William Wynne | wynne-001wil | 1904 | 102 g. | Jacksonville Jays | South Atlantic League | , | |
| William Wynne | wynne-001wil | 1904 | Augusta Tourists | South Atlantic League | , | ||
| Ad Yale | yale--001wil | 1904 | 116 g. | Bridgeport Orators | Connecticut State League | , | |
| Hogan Yancey | yancey001hog | 1904 | 92 g. | Jacksonville Jays | South Atlantic League | , | |
| Hogan Yancey | yancey001hog | 1904 | Savannah Pathfinders | South Atlantic League | , | ||
| Yates | yates-003--- | 1904 | 11 g. | Canton | Delta League | , | |
| Charles Yeager | yeager001cha | 1904 | 255 ab | Vicksburg Hill Billies | Cotton States League | , | |
| Elmer Yeager | yaeger001--- | 1904 | 8 g. | Fort Scott Giants | Missouri Valley League | , | |
| George Yeager | yeager001geo | 1904 | 4/20-9/20 | Columbus Senators | American Association | , | |
| Joe Yeager | yeager002jos | 1904 | 4/29-9/28 | Montreal Royals | Eastern League | , | |
| Robert Yeager | yeager003rob | 1904 | 8/13-8/15 | Paris Parasites/Ardmore Territorians | Texas League | , | |
| Ralph Yeazell | yeasel001lef | 1904 | 7/24 | Oakland Oaks | Pacific Coast League | , | |
| Armidas Yelle | 1904 | +5/29+ | Saginaw MI | Independent | , | ||
| Armidas Yelle | 1904 | +9/18+ | Sagi.-Zacharias | Independent | , | ||
| Stan Yerkes | yerkes001sta | 1904 | 25 g. | San Francisco Seals | Pacific Coast League | , | |
| Stan Yerkes | yerkes001sta | 1904 | 7/22-9/26 | Buffalo Bisons | Eastern League | , | |
| Joseph Yessler | 1904 | +4/20-6/11+ | Univ. of Iowa | College | , | ||
| John Yoedt | 1904 | Boone Coal Miners | Iowa League | , | |||
| J. Frank Yohe | 1904 | 18 g. | Sharon PA | Independent | , | ||
| Young | young-102--- | 1904 | 8/12-8/19 | Wellsville Oil Drillers | Southern Tier League | , | |
| Benjamin Young | 1904 | KC KS Central | High School | , | |||
| Cecil Young | young-001cec | 1904 | U. of Alabama | College | , | ||
| Cecil Young | young-001cec | 1904 | 5/16-7/7 | Anniston | Tennessee-Alabama League | , | |
| Cecil Young | young-001cec | 1904 | Sheffield | Tennessee-Alabama League | , | ||
| Cecil Young | young-001cec | 1904 | +8/3-8/20 | Huntsville | Tennessee-Alabama League | , | |
| Charles Young | young-002cha | 1904 | San Francisco | California State League | , | ||
| Charles Young | young-002cha | 1904 | 5/8-7/10 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Charles Young | young-002cha | 1904 | 7/12-7/20 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Elmer Young | young-001elm | 1904 | Pottstown PA | Independent | , | ||
| Elmer Young | young-001elm | 1904 | 9/27-9/30 | Lebanon | Tri-State League | , | |
| Irv Young | young-001irv | 1904 | 5/5-9/16 | Concord Marines | New England League | , | |
| Earnest Yount | 1904 | +4/11+ | Davidson Col | College | , | ||
| John Youst | youst-001--- | 1904 | Topeka Saints | Missouri Valley League | , | ||
| Elmer Zacher | zacher001elm | 1904 | Pottstown PA | Independent | , | ||
| Elmer Zacher | zacher001elm | 1904 | Buffalo-amat | , | |||
| Zackert | zacker003--- | 1904 | 8/10-8/11 | St. Joseph Saints | Western League | , | |
| Emil Zackert | 1904 | St. Jo.-Rex | St. Joseph City League | , | |||
| George Zackert | 1904 | St.Jo-Goetzes | St. Joseph City League | , | |||
| Jack Zalusky | zalusk001joh | 1904 | no g. | Toledo Mud Hens | American Association | , | |
| Jack Zalusky | zalusk001joh | 1904 | 5/11-8/13+ | Altoona Mountaineers | Tri-State League | , | |
| Joseph Zalusky | tilley001wil | 1904 | 5/6-6/29+ | Oskaloosa Quakers | Iowa League | , | |
| Joseph Zalusky | zalusk000jos | 1904 | +7/16-9/5 | Fort Dodge Gypsum Eaters | Iowa League | , | |
| Joseph Zalusky | zalusk000jos | 1904 | Penn College | College | , | ||
| G. R. Zarbaugh | zalusk000jos | 1904 | 3/27- | St.Jo.-Rex | St. Joseph City League | , | |
| G. R. Zarbaugh | zalusk000jos | 1904 | 5/22- | St.Jo.-Benedict | St. Joseph City League | , | |
| G. R. Zarbaugh | zalusk000jos | 1904 | +6/21-6/23+ | Oskaloosa Quakers | Iowa League | , | |
| G. R. Zarbaugh | zalusk000jos | 1904 | 7/13-7/15 | Topeka Saints | Missouri Valley League | , | |
| Dave Zearfoss | zearfo001dav | 1904 | 27 g. | St. Louis | National League | St. Louis, MO | |
| Louis Zehner | zehner001lou | 1904 | 318 ab | Baton Rouge Red Sticks | Cotton States League | , | |
| Gus Zeimer | zeimer001gus | 1904 | 5/6-7/10 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| Gus Zeimer | zeimer001gus | 1904 | 7/12-9/17 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| John Zeller | zeller001j-- | 1904 | no g. | Manchester | New England League | , | |
| John Zeller | zeller001j-- | 1904 | 5/21 | Concord Marines | New England League | , | |
| John Zeller | zeller001j-- | 1904 | 6/9-6/14 | Schenectady Electricians/Scranton Miners | New York State League | , | |
| John Zeller | zeller001j-- | 1904 | Spencer MA | Independent | , | ||
| John Ziegler | ziegle001joh | 1904 | 5/11-5/14 | Binghamton Bingoes | New York State League | , | |
| John Ziegler | ziegle001joh | 1904 | 6/7-8/5 | Pottstown PA | Independent | , | |
| Charles Zimmer | zimmer001cha | 1904 | 151 g. | MLB Umpire | National League | , | |
| Eddie Zimmerman | zimmer001edw | 1904 | 6/18-9/30 | Lebanon | Tri-State League | , | |
| Bill Zink | zink--001wil | 1904 | 5/19- | 61 g. | Duluth White Sox | Northern League | , |
| Bill Zink | zink--001wil | 1904 | +8/10-9/5 | Ottumwa Standpatters | Iowa League | , | |
| Ned Zinkins | 1904 | Umpire | Kentucky-Illinois-Tennessee League | , | |||
| Eddie Zinram | zinram001edw | 1904 | 4/26-9/24 | Little Rock Travelers | Southern Association | , | |
| Charles Zinzer | zinzer001cha | 1904 | 5/6-9/17 | Amsterdam-Gloversville-Johnstown Hyphens | New York State League | , | |
| Joe Zoellers | zoelle002jos | 1904 | 120 g. | Springfield Midgets | Missouri Valley League | , | |
| Harry Zollers | zoelle001har | 1904 | Oxford | Pennsylvania League | , | ||
| Earl Zook | zook--001ear | 1904 | Paris Parasites/Ardmore Territorians | Texas League | , | ||
| B. I. Zukowski | zukows000bi- | 1904 | 8/20 | Grand Rapids Orphans | Central League | , | |
| August Zurlage | zurlag001a-- | 1904 | Greenfield IN | Independent | , |