| 2012 NL Leaders | |||||||||||||||||
| Name | Age | Team | G | W | L | IP | TBF | H | 2B | 3B | HR | R | ER | BB | SO | ERA | RA9 |
| Jeremy Horst | Philadelphia | 32 | 2 | 0 | 31.1 | 125 | 21 | 6 | 0 | 1 | 8 | 6 | 14 | 40 | 1.72 | 2.30 | |
| J.J. Hoover | Cincinnati | 28 | 1 | 0 | 30.2 | 123 | 17 | 3 | 1 | 2 | 7 | 7 | 13 | 31 | 2.05 | 2.05 | |
| Michael Bowden | 26 | Chi Cubs | 30 | 0 | 0 | 36.2 | 154 | 30 | 7 | 0 | 4 | 12 | 12 | 16 | 29 | 2.95 | 2.95 |
| Eric O'Flaherty | 27 | Atlanta | 64 | 3 | 0 | 57.1 | 230 | 47 | 6 | 0 | 3 | 14 | 11 | 19 | 46 | 1.73 | 2.20 |
| Shane Loux | 33 | San Francisco | 19 | 1 | 0 | 25.1 | 112 | 32 | 9 | 1 | 3 | 15 | 14 | 9 | 9 | 4.97 | 5.33 |
| Luis Avilan | 23 | Atlanta | 31 | 1 | 0 | 36.0 | 142 | 27 | 5 | 0 | 1 | 9 | 8 | 10 | 33 | 2.00 | 2.25 |
| Bradley Boxberger | San Diego | 24 | 0 | 0 | 27.2 | 120 | 22 | 5 | 1 | 3 | 12 | 8 | 18 | 33 | 2.60 | 3.90 | |
| Tyler Thornburg | Milwaukee | 8 | 0 | 0 | 22.0 | 95 | 24 | 2 | 0 | 8 | 11 | 11 | 7 | 20 | 4.50 | 4.50 | |
| Luke Gregerson | 28 | San Diego | 77 | 2 | 0 | 71.2 | 294 | 57 | 10 | 0 | 7 | 19 | 19 | 21 | 72 | 2.39 | 2.39 |
| Craig Breslow | 32 | Arizona | 40 | 2 | 0 | 43.1 | 180 | 38 | 7 | 1 | 5 | 15 | 13 | 13 | 42 | 2.70 | 3.12 |
| Mike Gonzalez | 34 | Washington | 47 | 0 | 0 | 35.2 | 151 | 31 | 10 | 1 | 2 | 14 | 12 | 16 | 39 | 3.03 | 3.53 |
| Michael Zagurski | 30 | Arizona | 45 | 0 | 0 | 37.1 | 163 | 37 | 7 | 2 | 5 | 24 | 23 | 19 | 34 | 5.55 | 5.79 |
| Nick Vincent | San Diego | 27 | 2 | 0 | 26.1 | 105 | 19 | 3 | 0 | 2 | 5 | 5 | 7 | 28 | 1.71 | 1.71 | |
| Javier Lopez | 35 | San Francisco | 70 | 3 | 0 | 36.0 | 153 | 37 | 8 | 1 | 1 | 13 | 11 | 14 | 28 | 2.75 | 3.25 |
| Jacob Diekman | Philadelphia | 32 | 1 | 1 | 27.1 | 131 | 25 | 7 | 0 | 1 | 17 | 12 | 20 | 35 | 3.95 | 5.60 | |
| Craig Stammen | 28 | Washington | 59 | 6 | 1 | 88.1 | 370 | 70 | 18 | 1 | 7 | 27 | 23 | 36 | 87 | 2.34 | 2.75 |
| Brad Penny | 34 | San Francisco | 22 | 0 | 1 | 28.0 | 133 | 42 | 8 | 0 | 4 | 22 | 19 | 9 | 10 | 6.11 | 7.07 |
| Edgar Gonzalez | 29 | Houston | 6 | 3 | 1 | 25.0 | 105 | 23 | 5 | 2 | 3 | 14 | 14 | 8 | 18 | 5.04 | 5.04 |
| Rhinel Cruz | Houston | 52 | 1 | 1 | 55.0 | 253 | 65 | 14 | 2 | 8 | 38 | 37 | 29 | 46 | 6.05 | 6.22 | |
| Bradley Bergesen | 27 | Arizona | 19 | 2 | 1 | 29.2 | 121 | 29 | 7 | 1 | 2 | 14 | 12 | 7 | 18 | 3.64 | 4.25 |
| Brad Ziegler | 33 | Arizona | 77 | 6 | 1 | 68.2 | 263 | 53 | 6 | 1 | 2 | 21 | 19 | 21 | 42 | 2.49 | 2.75 |
| Charles Fick | Houston | 18 | 0 | 1 | 23.0 | 107 | 24 | 4 | 1 | 4 | 13 | 11 | 17 | 17 | 4.30 | 5.09 | |
| Ronald Belizario | LA Dodgers | 68 | 8 | 1 | 71.0 | 286 | 47 | 12 | 1 | 3 | 22 | 20 | 29 | 69 | 2.54 | 2.79 | |
| Chad Durbin | 35 | Atlanta | 76 | 4 | 1 | 61.0 | 257 | 52 | 8 | 1 | 9 | 25 | 21 | 28 | 49 | 3.10 | 3.69 |
| Edgmer Escalona | Colorado | 22 | 0 | 1 | 22.1 | 97 | 23 | 3 | 2 | 5 | 16 | 15 | 7 | 21 | 6.05 | 6.45 | |
| Scott Elbert | 27 | LA Dodgers | 43 | 1 | 1 | 32.2 | 133 | 27 | 3 | 0 | 3 | 8 | 8 | 13 | 29 | 2.20 | 2.20 |
| Mitchell Boggs | 28 | St. Louis | 78 | 4 | 1 | 73.1 | 296 | 56 | 6 | 0 | 5 | 20 | 18 | 21 | 58 | 2.21 | 2.45 |
| Alberto Cabrera | 24 | Chi Cubs | 25 | 1 | 1 | 21.2 | 99 | 16 | 4 | 1 | 1 | 15 | 13 | 18 | 27 | 5.40 | 6.23 |
| Craig Kimbrel | Atlanta | 63 | 3 | 1 | 62.2 | 231 | 27 | 1 | 0 | 3 | 7 | 7 | 14 | 116 | 1.01 | 1.01 | |
| Miles Mikolas | San Diego | 25 | 2 | 1 | 32.1 | 144 | 32 | 5 | 1 | 4 | 15 | 13 | 15 | 23 | 3.62 | 4.18 | |
