| 2012 NL Leaders | |||||||||||||
| Name | Age | Team | G | IP | TBF | BB% | K% | BABIP | LOB% | GB% | HR/Air | ERA | FIP |
| Craig Kimbrel | Atlanta | 63 | 62.67 | 231 | 6.1% | 50.2% | .250 | 93% | 50% | 6% | 1.01 | 0.81 | |
| Thomas Layne | 28 | San Diego | 26 | 16.67 | 68 | 4.4% | 36.8% | .250 | 60% | 48% | 0% | 3.24 | 1.21 |
| Aroldis Chapman | Cincinnati | 68 | 71.67 | 276 | 8.3% | 44.2% | .254 | 87% | 38% | 5% | 1.51 | 1.58 | |
| Shelby Miller | St. Louis | 6 | 13.67 | 54 | 7.4% | 29.6% | .273 | 86% | 44% | 0% | 1.32 | 1.88 | |
| Jim Henderson | 30 | Milwaukee | 36 | 30.67 | 131 | 9.9% | 34.4% | .358 | 72% | 43% | 2% | 3.23 | 1.99 |
| Julio Teheran | 22 | Atlanta | 2 | 6.33 | 24 | 4.2% | 20.8% | .278 | 33% | 24% | 0% | 5.69 | 2.02 |
| Matt Lindstrom | 32 | Arizona | 12 | 10.67 | 45 | 4.4% | 22.2% | .312 | 77% | 53% | 0% | 2.53 | 2.10 |
| David Hernandez | 27 | Arizona | 72 | 68.33 | 278 | 7.9% | 35.3% | .295 | 77% | 31% | 4% | 2.37 | 2.12 |
| Jose Mijares | 28 | San Francisco | 27 | 17.67 | 74 | 10.8% | 27.0% | .326 | 77% | 36% | 0% | 2.55 | 2.22 |
| Huston Street | 29 | San Diego | 40 | 39.00 | 144 | 7.6% | 32.6% | .185 | 79% | 44% | 4% | 1.85 | 2.23 |
| Vinnie Chulk | 34 | Milwaukee | 7 | 9.00 | 48 | 8.3% | 20.8% | .515 | 52% | 26% | 0% | 10.00 | 2.24 |
| Sean Marshall | 30 | Cincinnati | 73 | 61.00 | 256 | 6.3% | 28.9% | .329 | 80% | 58% | 4% | 2.51 | 2.28 |
| Edward Mujica | 28 | St. Louis | 29 | 26.33 | 97 | 3.1% | 21.6% | .271 | 93% | 51% | 3% | 1.03 | 2.37 |
| J.J. Putz | 35 | Arizona | 57 | 54.33 | 218 | 5.0% | 29.8% | .311 | 76% | 46% | 5% | 2.82 | 2.41 |
| Mike Pelfrey | 28 | NY Mets | 3 | 19.67 | 85 | 4.7% | 15.3% | .358 | 82% | 53% | 0% | 2.29 | 2.42 |
| Jeremy Horst | Philadelphia | 32 | 31.33 | 125 | 11.2% | 32.0% | .299 | 81% | 45% | 3% | 1.72 | 2.43 | |
| Drew Storen | Washington | 37 | 30.33 | 116 | 6.9% | 20.7% | .272 | 74% | 53% | 0% | 2.37 | 2.44 | |
| Kenley Jansen | 25 | LA Dodgers | 65 | 65.00 | 252 | 8.7% | 39.3% | .225 | 81% | 34% | 7% | 2.35 | 2.44 |
| Kristopher Medlen | 27 | Atlanta | 50 | 138.00 | 520 | 4.4% | 23.1% | .262 | 85% | 55% | 4% | 1.57 | 2.45 |
| Jonathan Broxton | 28 | Cincinnati | 25 | 22.33 | 87 | 3.4% | 23.0% | .306 | 75% | 49% | 3% | 2.82 | 2.46 |
| Zach Duke | 29 | Washington | 8 | 13.67 | 56 | 7.1% | 17.9% | .262 | 87% | 40% | 0% | 1.32 | 2.54 |
| Zack Greinke | 29 | Milwaukee | 21 | 123.00 | 504 | 5.6% | 24.2% | .328 | 72% | 54% | 4% | 3.44 | 2.57 |
| Luis Avilan | 23 | Atlanta | 31 | 36.00 | 142 | 7.0% | 23.2% | .280 | 79% | 45% | 2% | 2.00 | 2.57 |
| Raul Valdes | Philadelphia | 27 | 31.00 | 113 | 4.4% | 31.0% | .221 | 69% | 25% | 6% | 2.90 | 2.61 | |
| Wily Peralta | 23 | Milwaukee | 6 | 29.00 | 113 | 9.7% | 20.4% | .316 | 77% | 53% | 0% | 2.48 | 2.68 |
| Chad Qualls | 34 | Pittsburgh | 17 | 13.67 | 58 | 3.4% | 10.3% | .292 | 31% | 55% | 0% | 6.58 | 2.69 |
| Sergio Romo | 29 | San Francisco | 69 | 55.33 | 215 | 4.7% | 29.3% | .242 | 91% | 48% | 7% | 1.79 | 2.73 |
| Wilton Lopez | Houston | 64 | 66.33 | 260 | 3.1% | 20.8% | .310 | 81% | 55% | 5% | 2.17 | 2.74 | |
| Jeremy Affeldt | 33 | San Francisco | 67 | 63.33 | 267 | 8.6% | 21.3% | .315 | 74% | 61% | 1% | 2.70 | 2.76 |
| Jose Contreras | 41 | Philadelphia | 17 | 13.67 | 56 | 5.4% | 26.8% | .343 | 45% | 55% | 6% | 5.27 | 2.76 |
