| 2012 NL Leaders | |||||||||||||||||
| Name | Age | Team | G | W | L | IP | TBF | H | 2B | 3B | HR | R | ER | BB | SO | ERA | RA9 |
| Steven Rodriguez | LA Dodgers | 11 | 0 | 1 | 6.2 | 26 | 3 | 0 | 0 | 0 | 1 | 1 | 4 | 6 | 1.35 | 1.35 | |
| Justin Wilson | 25 | Pittsburgh | 8 | 0 | 0 | 4.2 | 26 | 10 | 3 | 0 | 0 | 1 | 1 | 3 | 7 | 1.93 | 1.93 |
| Brian Wilson | 30 | San Francisco | 2 | 0 | 0 | 2.0 | 12 | 4 | 2 | 0 | 0 | 2 | 2 | 2 | 2 | 9.00 | 9.00 |
| Miguel Batista | 41 | NY Mets | 30 | 1 | 3 | 46.2 | 220 | 52 | 11 | 0 | 5 | 28 | 22 | 31 | 34 | 4.24 | 5.40 |
| Rick Vanden Hurk | Pittsburgh | 4 | 0 | 1 | 2.2 | 16 | 5 | 0 | 0 | 0 | 4 | 4 | 1 | 3 | 13.48 | 13.48 | |
| Alexander Hinshaw | 30 | San Diego | 31 | 1 | 1 | 28.0 | 129 | 23 | 4 | 0 | 5 | 14 | 14 | 20 | 36 | 4.50 | 4.50 |
| Ernesto Frieri | 27 | San Diego | 11 | 1 | 0 | 11.2 | 50 | 9 | 1 | 0 | 2 | 5 | 3 | 4 | 18 | 2.31 | 3.86 |
| J.J. Putz | 35 | Arizona | 57 | 1 | 5 | 54.1 | 218 | 45 | 10 | 0 | 4 | 18 | 17 | 11 | 65 | 2.82 | 2.98 |
| Joshua Spence | San Diego | 11 | 0 | 1 | 10.1 | 48 | 13 | 1 | 0 | 1 | 5 | 5 | 5 | 10 | 4.36 | 4.36 | |
| Lendy Castillo | 23 | Chi Cubs | 13 | 0 | 1 | 16.0 | 88 | 24 | 3 | 0 | 2 | 16 | 14 | 12 | 13 | 7.88 | 9.00 |
| Trevor Rosenthal | St. Louis | 19 | 0 | 2 | 22.2 | 89 | 14 | 1 | 0 | 2 | 7 | 7 | 7 | 25 | 2.78 | 2.78 | |
| Francisco Cordero | 37 | Houston | 6 | 3 | 8 | 5.0 | 32 | 13 | 4 | 0 | 2 | 11 | 11 | 4 | 5 | 19.80 | 19.80 |
| Jonathon Niese | 26 | NY Mets | 30 | 13 | 9 | 190.1 | 788 | 174 | 29 | 0 | 22 | 77 | 72 | 49 | 155 | 3.40 | 3.64 |
| Micah Owings | 30 | San Diego | 6 | 0 | 2 | 9.2 | 41 | 8 | 2 | 0 | 1 | 4 | 3 | 5 | 7 | 2.79 | 3.72 |
| Barret Browning | 28 | St. Louis | 22 | 1 | 3 | 19.1 | 84 | 18 | 5 | 0 | 2 | 11 | 11 | 7 | 11 | 5.12 | 5.12 |
| Jorge De La Rosa | 31 | Colorado | 3 | 0 | 2 | 10.2 | 53 | 17 | 3 | 0 | 5 | 14 | 11 | 2 | 6 | 9.28 | 11.81 |
| Nick Vincent | San Diego | 27 | 2 | 0 | 26.1 | 105 | 19 | 3 | 0 | 2 | 5 | 5 | 7 | 28 | 1.71 | 1.71 | |
| Tyler Skaggs | Arizona | 6 | 1 | 3 | 29.1 | 133 | 30 | 4 | 0 | 6 | 20 | 19 | 13 | 21 | 5.83 | 6.14 | |
| Scott Elbert | 27 | LA Dodgers | 43 | 1 | 1 | 32.2 | 133 | 27 | 3 | 0 | 3 | 8 | 8 | 13 | 29 | 2.20 | 2.20 |
| Takashi Saito | 42 | Arizona | 16 | 0 | 0 | 12.0 | 60 | 17 | 8 | 0 | 4 | 14 | 9 | 5 | 11 | 6.75 | 10.50 |
| Mark Rogers | 26 | Milwaukee | 7 | 3 | 1 | 39.0 | 165 | 36 | 10 | 0 | 5 | 17 | 17 | 14 | 41 | 3.92 | 3.92 |
| Livan Hernandez | 37 | Atlanta | 18 | 1 | 1 | 31.0 | 136 | 40 | 5 | 0 | 5 | 17 | 17 | 8 | 19 | 4.94 | 4.94 |
| Andrew Cashner | 26 | San Diego | 33 | 3 | 4 | 46.1 | 196 | 42 | 6 | 0 | 5 | 23 | 22 | 19 | 52 | 4.27 | 4.47 |
| Jonathan Albaladejo | 30 | Arizona | 3 | 0 | 0 | 3.0 | 15 | 5 | 2 | 0 | 1 | 3 | 3 | 0 | 2 | 9.00 | 9.00 |
| Evan Meek | 29 | Pittsburgh | 12 | 0 | 0 | 12.0 | 57 | 14 | 2 | 0 | 1 | 9 | 9 | 6 | 8 | 6.75 | 6.75 |
| Jose Valdez | 30 | Houston | 12 | 0 | 0 | 12.0 | 57 | 12 | 1 | 0 | 1 | 4 | 3 | 8 | 10 | 2.25 | 3.00 |
| Logan Ondrusek | 27 | Cincinnati | 63 | 5 | 2 | 54.2 | 243 | 51 | 8 | 0 | 8 | 23 | 21 | 31 | 39 | 3.46 | 3.79 |
| Matt Guerrier | 34 | LA Dodgers | 16 | 0 | 2 | 14.0 | 56 | 8 | 1 | 0 | 3 | 6 | 6 | 7 | 9 | 3.86 | 3.86 |
| Randall Delgado | 22 | Atlanta | 18 | 4 | 9 | 92.2 | 401 | 89 | 21 | 0 | 8 | 48 | 45 | 42 | 76 | 4.37 | 4.66 |
| Joshua Edgin | NY Mets | 34 | 1 | 2 | 25.2 | 107 | 20 | 4 | 0 | 5 | 14 | 13 | 10 | 30 | 4.56 | 4.91 | |
