| 2012 NL Leaders | |||||||||||||
| Name | Age | Team | G | IP | TBF | BB% | K% | BABIP | LOB% | GB% | HR/Air | ERA | FIP |
| Matt Belisle | 32 | Colorado | 80 | 80.00 | 348 | 5.2% | 19.8% | .352 | 72% | 50% | 4% | 3.71 | 3.00 |
| Shawn Camp | 37 | Chi Cubs | 80 | 77.67 | 327 | 6.4% | 16.5% | .303 | 75% | 48% | 5% | 3.48 | 3.72 |
| Francisco Rodriguez | 29 | Milwaukee | 78 | 72.00 | 305 | 10.2% | 23.6% | .302 | 70% | 42% | 7% | 4.38 | 3.86 |
| Mitchell Boggs | 28 | St. Louis | 78 | 73.33 | 296 | 7.1% | 19.6% | .252 | 82% | 54% | 5% | 2.21 | 3.45 |
| Brad Ziegler | 33 | Arizona | 77 | 68.67 | 263 | 8.0% | 16.0% | .267 | 75% | 77% | 4% | 2.49 | 3.24 |
| Wesley Wright | 28 | Houston | 77 | 52.33 | 223 | 7.6% | 24.2% | .291 | 77% | 57% | 6% | 3.27 | 3.38 |
| Luke Gregerson | 28 | San Diego | 77 | 71.67 | 294 | 7.1% | 24.5% | .272 | 87% | 51% | 7% | 2.39 | 3.39 |
| James Russell | 26 | Chi Cubs | 77 | 69.33 | 292 | 7.9% | 18.8% | .306 | 74% | 39% | 4% | 2.99 | 3.52 |
| Chad Durbin | 35 | Atlanta | 76 | 61.00 | 257 | 10.9% | 19.1% | .262 | 82% | 48% | 10% | 3.10 | 4.82 |
| Rex Brothers | Colorado | 75 | 67.67 | 295 | 12.5% | 28.1% | .372 | 72% | 48% | 6% | 3.86 | 3.32 | |
| John Axford | Milwaukee | 75 | 69.33 | 310 | 12.6% | 30.0% | .317 | 68% | 47% | 11% | 4.80 | 4.09 | |
| Tyler Clippard | 27 | Washington | 74 | 72.67 | 307 | 9.4% | 27.4% | .273 | 71% | 30% | 5% | 3.72 | 3.35 |
| Bobby Parnell | 28 | NY Mets | 74 | 68.67 | 288 | 6.9% | 21.2% | .309 | 77% | 61% | 5% | 2.49 | 3.03 |
| Jon Rauch | 34 | NY Mets | 73 | 57.67 | 233 | 5.2% | 18.0% | .232 | 62% | 38% | 6% | 3.59 | 3.93 |
| Sean Marshall | 30 | Cincinnati | 73 | 61.00 | 256 | 6.3% | 28.9% | .329 | 80% | 58% | 4% | 2.51 | 2.28 |
| Santiago Casilla | 32 | San Francisco | 73 | 63.33 | 272 | 8.1% | 20.2% | .263 | 81% | 55% | 9% | 2.84 | 4.17 |
| David Hernandez | 27 | Arizona | 72 | 68.33 | 278 | 7.9% | 35.3% | .295 | 77% | 31% | 4% | 2.37 | 2.12 |
| Jose Veras | 32 | Milwaukee | 72 | 67.00 | 300 | 13.3% | 26.3% | .329 | 77% | 47% | 5% | 3.63 | 3.62 |
| Matthew Reynolds | Colorado | 71 | 57.33 | 249 | 6.8% | 20.5% | .340 | 77% | 40% | 10% | 4.40 | 4.73 | |
| Fernando Rodriguez | 28 | Houston | 71 | 70.33 | 309 | 11.0% | 25.2% | .331 | 65% | 38% | 9% | 5.37 | 4.25 |
| Kameron Loe | 31 | Milwaukee | 70 | 68.33 | 303 | 6.6% | 18.2% | .330 | 68% | 57% | 9% | 4.61 | 4.24 |
| Javier Lopez | 35 | San Francisco | 70 | 36.00 | 153 | 9.2% | 18.3% | .343 | 77% | 58% | 2% | 2.75 | 3.10 |
| Marc Rzepczynski | St. Louis | 70 | 46.67 | 196 | 8.7% | 16.8% | .285 | 77% | 59% | 12% | 4.24 | 4.76 | |
| Jonathan Papelbon | 32 | Philadelphia | 70 | 70.00 | 284 | 6.3% | 32.4% | .310 | 84% | 44% | 8% | 2.83 | 2.93 |
| Sean Burnett | 30 | Washington | 70 | 56.67 | 239 | 5.0% | 23.8% | .344 | 85% | 60% | 6% | 2.38 | 2.83 |
| Sergio Romo | 29 | San Francisco | 69 | 55.33 | 215 | 4.7% | 29.3% | .242 | 91% | 48% | 7% | 1.79 | 2.73 |
| Ronald Belizario | LA Dodgers | 68 | 71.00 | 286 | 10.1% | 24.1% | .250 | 77% | 65% | 5% | 2.54 | 3.13 | |
| Anthony Watson | 27 | Pittsburgh | 68 | 53.33 | 215 | 10.7% | 24.7% | .250 | 74% | 41% | 6% | 3.38 | 3.71 |
| Aroldis Chapman | Cincinnati | 68 | 71.67 | 276 | 8.3% | 44.2% | .254 | 87% | 38% | 5% | 1.51 | 1.58 | |
| Brad Brach | San Diego | 67 | 66.67 | 280 | 11.8% | 26.8% | .264 | 82% | 37% | 11% | 3.78 | 4.60 | |
