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. | Joss, Addie | (dunroche) | Detroit Tigers | 30 |
| 2. | McLain, Denny | (dunroche) | Chenango Wolves | 30 |
| 3. | Koufax, Sandy | (dunroche) | Chenango Wolves | 29 |
| 4. | Hamels, Cole | (filler) | Springer Wolves | 29 |
| 5. | Andujar, Joaquin | (Majestic44) | Albuquerque Mustangs | 29 |
| 6. | Sabathia, CC | (dynasty) | Florida Gators | 29 |
| 7. | McGinnity, Joe | (filler8) | Treasure Island ROBBERS | 29 |
| 8. | Plesac, Zach | (hanson) | Oconee Riverdawgs | 29 |
| 9. | Hershiser, Orel | (Poisonwildcat) | Shreveport Sharks | 29 |
| 10. | Sutton, Don | (dunroche) | South Dakota Dragons | 29 |
| 11. | Drysdale, Don | (filler8) | Algiers Point Poo Flingers | 29 |
| 12. | Hendrix, Claude | (filler) | Seattle Pilots | 28 |
| 13. | Pfiester, Jack | (filler) | Seattle Pilots | 28 |
| 14. | Joss, Addie | (JohnHeidy) | Highland Hi-Ballers | 28 |
| 15. | Halladay, Roy | (rreebe916) | South Dakota Suns | 28 |
| 16. | Krukow, Mike | (govols1975) | Kenora Thistles | 28 |
| 17. | Chance, Dean | (dynasty) | JACKSONVILLE JACKS | 28 |
| 18. | Shields, James | (filler) | Schvitz Sweatmen | 28 |
| 19. | Swindell, Greg | (dynasty) | Denver Reds | 28 |
| 20. | Tanana, Frank | (filler) | Orlando VA | 28 |
| 21. | Taylor, Jack | (filler) | Portland Bounty | 28 |
| 22. | McLain, Denny | (dunroche) | Tuvalu Copras | 28 |
| 23. | White, Doc | (filler) | Harrisburg Cougars | 28 |
| 24. | Bender, Chief | (DLJONES) | DELTA THUMPERS | 28 |
| 25. | Cicotte, Eddie | (dynasty) | Toronto Devils | 28 |
| 26. | Newcombe, Don | (filler8) | Chicago Cougars | 28 |
| 27. | Lyons, Ted | (Dodger1973) | Butte Pirates | 28 |
| 28. | Drysdale, Don | (filler8) | Mighty Mites | 28 |
| 29. | Wood, Joe | (whtsittou83) | Gwangju Craxy | 28 |
| 30. | Sutton, Don | (dynasty) | LITTLE ROCK RAZORBACKS | 28 |
| 31. | Ford, Whitey | (Trulaia) | Huron Herons | 28 |
| 32. | Saberhagen, Bret | (dynasty) | Chenango Wolves | 28 |
| 33. | White, Doc | (filler8) | Chicago Logan Squares | 28 |
| 34. | Cicotte, Eddie | (filler) | Nakatomi Die Hards | 28 |
| 35. | McGinnity, Joe | (filler8) | Halifax Hackers | 28 |
| 36. | Blyleven, Bert | (filler) | Houston Wolves | 28 |
| 37. | Chesbro, Jack | (dynasty) | new jersey bandits | 28 |
| 38. | Sweeney, Charlie | (mdsyverson) | Saskatchewan Saskatoons | 28 |
| 39. | Cooke, Steve | (filler8) | Washington MO Borja Knights | 28 |
| 40. | Horlen, Joe | (dunroche) | Toledo Mudhens | 27 |
| 41. | Cooper, Mort | (Pop) | Woodenville Waterfowls | 27 |
| 42. | White, Doc | (Pop) | Woodenville Waterfowls | 27 |
| 43. | Marichal, Juan | (filler) | Worcester Reapers | 27 |
| 44. | Smithson, Mike | (Majestic44) | Rapid city Sharks | 27 |
| 45. | Kaat, Jim | (Cubanlou) | Manhattan Americans | 27 |
| 46. | Norris, Mike | Lake Havasu Rain-2 | 27 | |
| 47. | Bunning, Jim | (dynasty) | Pinellas Park PEMF | 27 |
| 48. | Kluber, Corey | (dunroche) | Chenango Wolves | 27 |
| 49. | Krock, Gus | Boston Bandits | 27 | |
| 50. | Tudor, John | (ranger) | HOUSTON HEATERS | 27 |
