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 | (dunroche) | Chenango Wolves | 30 |
| 2. | Joss, Addie | (dunroche) | Detroit Tigers | 30 |
| 3. | McGinnity, Joe | (filler) | Treasure Island ROBBERS | 29 |
| 4. | Koufax, Sandy | (dunroche) | Chenango Wolves | 29 |
| 5. | Hamels, Cole | (filler) | Springer Wolves | 29 |
| 6. | Hershiser, Orel | (Poisonwildcat) | Shreveport Sharks | 29 |
| 7. | Sabathia, CC | (dynasty8) | Florida Gators | 29 |
| 8. | Tesreau, Jeff | (dynasty) | RED Bovini | 29 |
| 9. | Plesac, Zach | (hanson) | Oconee Riverdawgs | 29 |
| 10. | Sutton, Don | (dunroche) | South Dakota Dragons | 29 |
| 11. | Andujar, Joaquin | (dynasty) | Albuquerque Mustangs | 29 |
| 12. | Drysdale, Don | (filler) | Algiers Point Poo Flingers | 29 |
| 13. | Bender, Chief | (filler8) | DELTA THUMPERS | 28 |
| 14. | Shields, James | (dynasty) | Ellenton Traitors | 28 |
| 15. | Saberhagen, Bret | (ImUhKiNg23) | Boston Royalty | 28 |
| 16. | Taylor, Jack | (WorcWarr) | Worcester Warriors | 28 |
| 17. | Cicotte, Eddie | (dynasty) | Toronto Devils | 28 |
| 18. | Newcombe, Don | (dynasty) | Chicago Cougars | 28 |
| 19. | Chance, Dean | (dynasty) | JACKSONVILLE JACKS | 28 |
| 20. | Vander Meer, Johnny | (dynasty) | Riverdale Rams | 28 |
| 21. | White, Doc | (filler8) | Chicago Sippers | 28 |
| 22. | Cicotte, Eddie | Nakatomi Die Hards | 28 | |
| 23. | Wood, Joe | (dynasty8) | Gwangju Craxy | 28 |
| 24. | McLain, Denny | (dynasty8) | Tuvalu Copras | 28 |
| 25. | Lyons, Ted | (sheikyerboudi) | Falstaff Brewers | 28 |
| 26. | Drysdale, Don | MISSOURI TIGERS | 28 | |
| 27. | Sutton, Don | (filler8) | LITTLE ROCK RAZORBACKS | 28 |
| 28. | Ford, Whitey | (Cunnythumber) | Huron Herons | 28 |
| 29. | Sweeney, Charlie | (mdsyverson) | Saskatchewan Saskatoons | 28 |
| 30. | Tanana, Frank | (filler) | Orlando VA | 28 |
| 31. | Hendrix, Claude | (filler8) | Seattle Pilots | 28 |
| 32. | Pfiester, Jack | (filler8) | Seattle Pilots | 28 |
| 33. | White, Doc | (filler) | Harrisburg Cougars | 28 |
| 34. | McGinnity, Joe | (dynasty) | Halifax Hackers | 28 |
| 35. | Halladay, Roy | (Ask12be1) | Kings County HENCHMEN | 28 |
| 36. | Viola, Frank | (dynasty) | Wild Dogs | 28 |
| 37. | Krukow, Mike | (dynasty) | Kenora Thistles | 28 |
| 38. | Swindell, Greg | (dynasty8) | Denver Reds | 28 |
| 39. | Blyleven, Bert | (filler) | Houston Wolves | 28 |
| 40. | Pfiester, Jack | (LDJS1947) | SOUTH DAKOTA CAVALRY | 28 |
| 41. | Reulbach, Ed | (dynasty) | Escanaba Hilltoppers | 28 |
| 42. | Joss, Addie | (JohnHeidy) | Highland Hi-Ballers | 28 |
| 43. | Chesbro, Jack | (dynasty) | new jersey bandits | 28 |
| 44. | Pfiester, Jack | (dynasty) | BALTIMORE BOMBERS | 27 |
| 45. | Kluber, Corey | (dunroche) | Chenango Wolves | 27 |
| 46. | Krock, Gus | (filler) | Boston Bandits | 27 |
| 47. | Tudor, John | (filler) | SUGARLAND SPEED | 27 |
| 48. | Pfiester, Jack | (filler) | Red Wing Rhino's | 27 |
| 49. | Valdez, Ismael | (filler) | Ponbañaco Bank Robbers | 27 |
| 50. | Sanderson, Scott | (dynasty) | Long beach Devils | 27 |
