Favorite Teams leagues are not included in Single-Season records. Records only remain for 10 seasons.
Single-Season Leaders (Losses)
Average
OBP
SLG
OPS
At Bats
Runs
Hits
Doubles
Triples
Homers
RBIs
Walks
Strikeouts
Stolen Bases
Caught Stealing
Sac Hits
Sac Fly
HBP
GIDP
D+/-
Wins
Losses
ERA
WHIP
Innings
Hits Allowed
HR Allowed
Walks (P)
Strikeouts (p)
Complete Games
Saves
Blown Saves
Shutouts
Quality Starts
Wild Pitches
Hit Batters
H/9
BB/9
SO/9
| 1. | McLain, Denny | (filler) | Chenango Wolves | 30 |
| 2. | Joss, Addie | (filler) | Detroit Tigers | 30 |
| 3. | Hamels, Cole | (filler8) | Springer Wolves | 29 |
| 4. | Koufax, Sandy | (filler) | Chenango Wolves | 29 |
| 5. | McGinnity, Joe | (filler8) | Treasure Island ROBBERS | 29 |
| 6. | Sutton, Don | (filler) | South Dakota Dragons | 29 |
| 7. | Plesac, Zach | (hanson) | Oconee Riverdawgs | 29 |
| 8. | Tesreau, Jeff | (filler) | RED Bovini | 29 |
| 9. | Andujar, Joaquin | (jericho2u) | Sabotage Sure Shots | 29 |
| 10. | Drysdale, Don | (Swingindave) | ARKANSAS SWINGERS | 29 |
| 11. | Sabathia, CC | (dom1134157) | Florida Gators | 29 |
| 12. | Newcombe, Don | (dynasty) | Chicago Cougars | 28 |
| 13. | Chance, Dean | (walle-1) | JACKSONVILLE JACKS | 28 |
| 14. | Vander Meer, Johnny | (filler8) | Riverdale Rams | 28 |
| 15. | Lyons, Ted | (filler8) | Falstaff Brewers | 28 |
| 16. | Reulbach, Ed | (finalbody) | Escanaba Hilltoppers | 28 |
| 17. | Sutton, Don | (peteym17) | Pennsylvania Athletics | 28 |
| 18. | Ford, Whitey | (dynasty8) | Huron Herons | 28 |
| 19. | Sweeney, Charlie | (filler8) | Saskatchewan Saskatoons | 28 |
| 20. | Tanana, Frank | (dynasty) | Orlando VA | 28 |
| 21. | Taylor, Jack | (WorcWarr) | Worcester Warriors | 28 |
| 22. | Joss, Addie | (JohnHeidy) | Highland Hi-Ballers | 28 |
| 23. | McLain, Denny | (Dodgers1988) | Niagara Night Riders | 28 |
| 24. | Halladay, Roy | (rlapierre) | MAINE BLACK BEARS | 28 |
| 25. | Viola, Frank | (filler) | Wild Dogs | 28 |
| 26. | Cicotte, Eddie | (dkcoconutgun) | Toronto Devils | 28 |
| 27. | Wood, Joe | (idesofmarch) | Fort Worth Cats | 28 |
| 28. | Pfiester, Jack | (dynasty8) | SOUTH DAKOTA CAVALRY | 28 |
| 29. | Blyleven, Bert | (bostontex24) | Boston Wolves | 28 |
| 30. | Bender, Chief | (onionsama) | DELTA THUMPERS | 28 |
| 31. | Saberhagen, Bret | (filler8) | Berlin NatSocs | 28 |
| 32. | Drysdale, Don | (filler) | MISSOURI TIGERS | 28 |
| 33. | White, Doc | (filler8) | Chicago Sippers | 28 |
| 34. | Cicotte, Eddie | (filler8) | Nakatomi Die Hards | 28 |
| 35. | Shields, James | (filler8) | Ellenton Traitors | 28 |
| 36. | Krukow, Mike | (filler8) | Kenora Thistles | 28 |
| 37. | Hendrix, Claude | (filler) | Seattle Pilots | 28 |
| 38. | Pfiester, Jack | (filler) | Seattle Pilots | 28 |
| 39. | Chesbro, Jack | (dynasty) | new jersey bandits | 28 |
| 40. | Swindell, Greg | (Tonypsu7) | Denver Reds | 28 |
| 41. | White, Doc | (dynasty) | Harrisburg Cougars | 28 |
| 42. | McGinnity, Joe | (dynasty) | Halifax Hackers | 28 |
| 43. | Wood, Wilbur | (Mikep33) | Chicago Jets | 27 |
| 44. | Pfiester, Jack | (dynasty) | Red Wing Rhino's | 27 |
| 45. | Ford, Russ | (filler) | Detroit Tigers | 27 |
| 46. | Cicotte, Eddie | (JohnHeidy) | Hamburg Chili Dodgers | 27 |
| 47. | Valdez, Ismael | (jericho2u) | Sabotage Sure Shots | 27 |
| 48. | Kaat, Jim | (Cubanlou) | Manhattan Americans | 27 |
| 49. | Norris, Mike | (dynasty8) | Lake Havasu Rain-2 | 27 |
| 50. | Bunning, Jim | (filler8) | Pinellas Park PEMF | 27 |
