| 301 | George Manion |  |
| 302 | Rube Manning (Batting) |  |
| 303 | Rube Manning (Pitching) |  |
| 304 | Rube Marquard (Hands At Thighs) |  |
| 305 | Rube Marquard (Pitching Follow Through) |  |
| 306 | Rube Marquard (Portrait) |  |
| 307 | Doc Marshall |  |
| 308 | Christy Mathewson (Dark Cap) |  |
| 309 | Christy Mathewson (Portrait) |  |
| 310 | Christy Mathewson (White Cap) |  |
| 311 | Al Mattern |  |
| 312 | John McAleese |  |
| 313 | George McBride |  |
| 314 | Pat McCauley |  |
| 315 | Moose McCormick |  |
| 316 | Pryor McElveen |  |
| 317 | Dan McGann |  |
| 318 | Jim McGinley |  |
| 319 | Iron Man McGinnity |  |
| 320 | Stoney McGlynn |  |
| 321 | John McGraw (Finger In Air) |
 |
| 322 | John McGraw (Glove At Hip) |
 |
| 323 | John McGraw (Portrait No Cap) |  |
| 324 | John McGraw (Portrait With Cap) |  |
| 325 | Harry McIntyre (Brooklyn) |  |
| 326 | Harry McIntyre (Brooklyn & Chicago) |  |
| 327 | Matty McIntyre (Detroit) |
 |
| 328 | Larry McLean |  |
| 329 | George McQuillan (Ball In Hand) |  |
| 330 | George McQuillan (With Bat) |  |
| 331 | Fred Merkle (Portrait) |  |
| 332 | Fred Merkle (Throwing) | |
| 333 | George Merritt |  |
| 334 | Chief Meyers |  |
| 335 | Clyde Milan |  |
| 336 | Dots Miller (Pittsburgh) |  |
| 337 | Molly Miller (Dallas) |  |
| 338 | Bill Milligan |  |
| 339 | Fred Mitchell (Toronto) |  |
| 340 | Mike Mitchell (Cincinnati) |  |
| 341 | Dan Moeller |  |
| 342 | Carlton Molesworth |  |
| 343 | Herbie Moran (Providence) |
 |
| 344 | Pat Moran (Chicago) |  |
| 345 | George Moriarty |  |
| 346 | Mike Mowrey |  |
| 347 | Dom Mullaney |  |
| 348 | George Mullen (Mullin) | |
| 349 | George Mullin (Throwing) |  |
| 350 | George Mullin (With Bat) |  |