| 2012 NL Leaders | |||||||||||||||||
| Name | Age | Team | G | W | L | IP | TBF | H | 2B | 3B | HR | R | ER | BB | SO | ERA | RA9 |
| Craig Kimbrel | Atlanta | 63 | 3 | 1 | 62.2 | 231 | 27 | 1 | 0 | 3 | 7 | 7 | 14 | 116 | 1.01 | 1.01 | |
| Edward Mujica | 28 | St. Louis | 29 | 0 | 3 | 26.1 | 97 | 20 | 5 | 1 | 1 | 3 | 3 | 3 | 21 | 1.03 | 1.03 |
| Aroldis Chapman | Cincinnati | 68 | 5 | 5 | 71.2 | 276 | 35 | 7 | 1 | 4 | 13 | 12 | 23 | 122 | 1.51 | 1.63 | |
| Kristopher Medlen | 27 | Atlanta | 50 | 10 | 1 | 138.0 | 520 | 103 | 17 | 2 | 6 | 26 | 24 | 23 | 120 | 1.57 | 1.70 |
| Nick Vincent | San Diego | 27 | 2 | 0 | 26.1 | 105 | 19 | 3 | 0 | 2 | 5 | 5 | 7 | 28 | 1.71 | 1.71 | |
| Jeremy Horst | Philadelphia | 32 | 2 | 0 | 31.1 | 125 | 21 | 6 | 0 | 1 | 8 | 6 | 14 | 40 | 1.72 | 2.30 | |
| Eric O'Flaherty | 27 | Atlanta | 64 | 3 | 0 | 57.1 | 230 | 47 | 6 | 0 | 3 | 14 | 11 | 19 | 46 | 1.73 | 2.20 |
| Sergio Romo | 29 | San Francisco | 69 | 4 | 2 | 55.1 | 215 | 37 | 6 | 0 | 5 | 11 | 11 | 10 | 63 | 1.79 | 1.79 |
| Huston Street | 29 | San Diego | 40 | 2 | 1 | 39.0 | 144 | 17 | 5 | 1 | 2 | 8 | 8 | 11 | 47 | 1.85 | 1.85 |
| Brandon Beachey | Atlanta | 13 | 5 | 5 | 81.0 | 319 | 49 | 7 | 0 | 6 | 24 | 18 | 29 | 68 | 2.00 | 2.67 | |
| Luis Avilan | 23 | Atlanta | 31 | 1 | 0 | 36.0 | 142 | 27 | 5 | 0 | 1 | 9 | 8 | 10 | 33 | 2.00 | 2.25 |
| J.J. Hoover | Cincinnati | 28 | 1 | 0 | 30.2 | 123 | 17 | 3 | 1 | 2 | 7 | 7 | 13 | 31 | 2.05 | 2.05 | |
| Wilton Lopez | Houston | 64 | 6 | 3 | 66.1 | 260 | 61 | 10 | 1 | 4 | 18 | 16 | 8 | 54 | 2.17 | 2.44 | |
| 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 |
| Ryan Dempster | 35 | Chi Cubs | 16 | 5 | 5 | 104.0 | 417 | 80 | 13 | 2 | 9 | 28 | 26 | 27 | 83 | 2.25 | 2.42 |
| Brandon League | 29 | LA Dodgers | 28 | 2 | 6 | 27.1 | 108 | 17 | 3 | 0 | 0 | 7 | 7 | 14 | 27 | 2.31 | 2.31 |
| Craig Stammen | 28 | Washington | 59 | 6 | 1 | 88.1 | 370 | 70 | 18 | 1 | 7 | 27 | 23 | 36 | 87 | 2.34 | 2.75 |
| Kenley Jansen | 25 | LA Dodgers | 65 | 5 | 3 | 65.0 | 252 | 33 | 7 | 2 | 6 | 18 | 17 | 22 | 99 | 2.35 | 2.49 |
| Drew Storen | Washington | 37 | 3 | 1 | 30.1 | 116 | 22 | 2 | 0 | 0 | 8 | 8 | 8 | 24 | 2.37 | 2.37 | |
| David Hernandez | 27 | Arizona | 72 | 2 | 3 | 68.1 | 278 | 48 | 9 | 1 | 4 | 21 | 18 | 22 | 98 | 2.37 | 2.77 |
| Sean Burnett | 30 | Washington | 70 | 1 | 2 | 56.2 | 239 | 58 | 11 | 0 | 4 | 16 | 15 | 12 | 57 | 2.38 | 2.54 |
| Luke Gregerson | 28 | San Diego | 77 | 2 | 0 | 71.2 | 294 | 57 | 10 | 0 | 7 | 19 | 19 | 21 | 72 | 2.39 | 2.39 |
| George Kontos | 27 | San Francisco | 44 | 2 | 1 | 43.2 | 177 | 34 | 7 | 2 | 3 | 15 | 12 | 12 | 44 | 2.47 | 3.09 |
| Wily Peralta | 23 | Milwaukee | 6 | 2 | 1 | 29.0 | 113 | 24 | 4 | 0 | 0 | 8 | 8 | 11 | 23 | 2.48 | 2.48 |
| Bobby Parnell | 28 | NY Mets | 74 | 5 | 4 | 68.2 | 288 | 64 | 11 | 1 | 4 | 24 | 19 | 20 | 61 | 2.49 | 3.15 |
| Brad Ziegler | 33 | Arizona | 77 | 6 | 1 | 68.2 | 263 | 53 | 6 | 1 | 2 | 21 | 19 | 21 | 42 | 2.49 | 2.75 |
| Sean Marshall | 30 | Cincinnati | 73 | 5 | 5 | 61.0 | 256 | 55 | 7 | 1 | 3 | 18 | 17 | 16 | 74 | 2.51 | 2.66 |
| Clayton Kershaw | 24 | LA Dodgers | 33 | 14 | 9 | 227.2 | 901 | 170 | 38 | 3 | 16 | 70 | 64 | 63 | 229 | 2.53 | 2.77 |
| Ronald Belizario | LA Dodgers | 68 | 8 | 1 | 71.0 | 286 | 47 | 12 | 1 | 3 | 22 | 20 | 29 | 69 | 2.54 | 2.79 | |
