| SP | Prior, M.Prior, Mark † >> | 23 | 2003 | R | 94 | 23 | 23 | 7 | 8 | 3.25 | .279 | 1.14 | 7.1 | 3.2 | 8.6 | 169.0 | 133 | 61 | 61 | 14 | 60 | 162 | 5 | 0 | 0 | 3 | 14 | 3 | 4 | 3.28 |
| SP | Millwood, K.Millwood, Kevin >> | 29 | 2003 | R | 66 | 23 | 23 | 9 | 9 | 4.86 | .325 | 1.43 | 9.1 | 3.8 | 6.4 | 153.2 | 155 | 89 | 83 | 25 | 65 | 109 | 1 | 0 | 0 | 0 | 12 | 2 | 0 | 5.01 |
| SP | Chacon, S.Chacon, Shawn >> | 26 | 2003 | R | 42 | 22 | 22 | 5 | 10 | 5.35 | .342 | 1.54 | 10.0 | 3.9 | 6.0 | 131.1 | 145 | 83 | 78 | 20 | 57 | 87 | 0 | 0 | 0 | 0 | 9 | 3 | 5 | 5.03 |
| SP | Buehrle, M.Buehrle, Mark # >> | 24 | 2003 | L | 12 | 22 | 22 | 6 | 8 | 4.95 | .321 | 1.40 | 10.8 | 1.9 | 5.8 | 143.2 | 171 | 81 | 79 | 23 | 30 | 92 | 2 | 0 | 0 | 1 | 10 | 3 | 1 | 4.50 |
| RP | Isringhausen, J.Isringhausen, Jason >> | 31 | 2003 | R | 77 | 70 | 0 | 1 | 9 | 4.40 | .344 | 1.53 | 8.9 | 5.1 | 6.5 | 73.2 | 72 | 38 | 36 | 7 | 41 | 53 | 0 | 7 | 8 | 0 | 0 | 3 | 10 | 4.60 |
| RP | Ramirez, E.Ramirez, Erasmo # >> | 27 | 2003 | L | 55 | 52 | 0 | 6 | 4 | 5.98 | .371 | 1.71 | 12.3 | 3.3 | 5.5 | 49.2 | 67 | 36 | 33 | 5 | 18 | 30 | 0 | 4 | 2 | 0 | 0 | 3 | 2 | 4.39 |
| RP | Speier, J.Speier, Justin >> | 30 | 2003 | R | 28 | 24 | 0 | 0 | 1 | 3.86 | .345 | 1.52 | 9.9 | 3.9 | 8.1 | 30.1 | 33 | 13 | 13 | 1 | 13 | 27 | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 3.13 |