| 2012 NL Leaders | |||||||||||||||||
| Name | Age | Team | G | W | L | IP | TBF | H | 2B | 3B | HR | R | ER | BB | SO | ERA | RA9 |
| Zach Putnam | 25 | Colorado | 2 | 0 | 0 | 2.0 | 9 | 3 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0.00 | 0.00 |
| Daniel Runzler | San Francisco | 6 | 0 | 0 | 3.2 | 15 | 1 | 0 | 0 | 0 | 0 | 0 | 3 | 5 | 0.00 | 0.00 | |
| Joshua Stinson | 24 | Milwaukee | 6 | 0 | 0 | 9.1 | 38 | 7 | 2 | 0 | 1 | 1 | 1 | 5 | 3 | 0.96 | 0.96 |
| 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 |
| Rob Scahill | Colorado | 6 | 0 | 0 | 8.2 | 33 | 7 | 2 | 0 | 0 | 1 | 1 | 3 | 4 | 1.04 | 1.04 | |
| Zach Duke | 29 | Washington | 8 | 1 | 0 | 13.2 | 56 | 11 | 2 | 1 | 0 | 2 | 2 | 4 | 10 | 1.32 | 1.32 |
| Shelby Miller | St. Louis | 6 | 1 | 0 | 13.2 | 54 | 9 | 1 | 0 | 0 | 2 | 2 | 4 | 16 | 1.32 | 1.32 | |
| Steven Rodriguez | LA Dodgers | 11 | 0 | 1 | 6.2 | 26 | 3 | 0 | 0 | 0 | 1 | 1 | 4 | 6 | 1.35 | 1.35 | |
| 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 | |
| Sergio Romo | 29 | San Francisco | 69 | 4 | 2 | 55.1 | 215 | 37 | 6 | 0 | 5 | 11 | 11 | 10 | 63 | 1.79 | 1.79 |
| Tony Cingrani | Cincinnati | 3 | 0 | 0 | 5.0 | 22 | 4 | 0 | 0 | 1 | 1 | 1 | 2 | 9 | 1.80 | 1.80 | |
| Cory Gearrin | Atlanta | 22 | 0 | 1 | 20.0 | 80 | 17 | 3 | 1 | 1 | 4 | 4 | 5 | 20 | 1.80 | 1.80 | |
| Huston Street | 29 | San Diego | 40 | 2 | 1 | 39.0 | 144 | 17 | 5 | 1 | 2 | 8 | 8 | 11 | 47 | 1.85 | 1.85 |
| Justin Wilson | 25 | Pittsburgh | 8 | 0 | 0 | 4.2 | 26 | 10 | 3 | 0 | 0 | 1 | 1 | 3 | 7 | 1.93 | 1.93 |
| J.J. Hoover | Cincinnati | 28 | 1 | 0 | 30.2 | 123 | 17 | 3 | 1 | 2 | 7 | 7 | 13 | 31 | 2.05 | 2.05 | |
| Christian Garcia | 27 | Washington | 13 | 0 | 0 | 12.2 | 48 | 8 | 2 | 0 | 2 | 3 | 3 | 2 | 15 | 2.13 | 2.13 |
| Eric O'Flaherty | 27 | Atlanta | 64 | 3 | 0 | 57.1 | 230 | 47 | 6 | 0 | 3 | 14 | 11 | 19 | 46 | 1.73 | 2.20 |
| Scott Elbert | 27 | LA Dodgers | 43 | 1 | 1 | 32.2 | 133 | 27 | 3 | 0 | 3 | 8 | 8 | 13 | 29 | 2.20 | 2.20 |
| Luis Avilan | 23 | Atlanta | 31 | 1 | 0 | 36.0 | 142 | 27 | 5 | 0 | 1 | 9 | 8 | 10 | 33 | 2.00 | 2.25 |
| Mike Pelfrey | 28 | NY Mets | 3 | 0 | 0 | 19.2 | 85 | 24 | 2 | 1 | 0 | 5 | 5 | 4 | 13 | 2.29 | 2.29 |
| Jeremy Horst | Philadelphia | 32 | 2 | 0 | 31.1 | 125 | 21 | 6 | 0 | 1 | 8 | 6 | 14 | 40 | 1.72 | 2.30 | |
| Brandon League | 29 | LA Dodgers | 28 | 2 | 6 | 27.1 | 108 | 17 | 3 | 0 | 0 | 7 | 7 | 14 | 27 | 2.31 | 2.31 |
| Drew Storen | Washington | 37 | 3 | 1 | 30.1 | 116 | 22 | 2 | 0 | 0 | 8 | 8 | 8 | 24 | 2.37 | 2.37 | |
| Luke Gregerson | 28 | San Diego | 77 | 2 | 0 | 71.2 | 294 | 57 | 10 | 0 | 7 | 19 | 19 | 21 | 72 | 2.39 | 2.39 |
| Ryan Dempster | 35 | Chi Cubs | 16 | 5 | 5 | 104.0 | 417 | 80 | 13 | 2 | 9 | 28 | 26 | 27 | 83 | 2.25 | 2.42 |
| Wilton Lopez | Houston | 64 | 6 | 3 | 66.1 | 260 | 61 | 10 | 1 | 4 | 18 | 16 | 8 | 54 | 2.17 | 2.44 | |
| Mitchell Boggs | 28 | St. Louis | 78 | 4 | 1 | 73.1 | 296 | 56 | 6 | 0 | 5 | 20 | 18 | 21 | 58 | 2.21 | 2.45 |
