| East | W | L | Pct | GB |
| NY Yankees | 101 | 61 | .623 | -- |
| Boston | 95 | 67 | .586 | 6.0 |
| Toronto | 86 | 76 | .531 | 15.0 |
| Baltimore | 71 | 91 | .438 | 30.0 |
| Tampa Bay | 63 | 99 | .389 | 38.0 |
| Date | Pitcher | Hand | Age | Game Result | Opp | GS# | Career | Dec | IP | H | R | ER | HR | BB | SO | Pit | Bal | Str | Str% | W-L | ERA | WHIP |
| 2003-03-31 | Pedro Martinez | R | 31 | L 4-6 | @ TBA | 1 | 260 | - | 7.0 | 3 | 1 | 0 | 0 | 1 | 6 | 87 | 30 | 57 | 66% | 0-0 | 0.00 | 0.57 |
| 2003-04-01 | Tim Wakefield | R | 37 | W 9-8 | @ TBA | 1 | 221 | - | 5.0 | 5 | 5 | 5 | 1 | 3 | 6 | 96 | 35 | 61 | 64% | 0-0 | 9.00 | 1.60 |
| 2003-04-02 | Derek Lowe | R | 30 | W 7-5 | @ TBA | 1 | 55 | W | 6.0 | 6 | 5 | 5 | 1 | 2 | 3 | 85 | 37 | 48 | 56% | 1-0 | 7.50 | 1.33 |
| 2003-04-03 | Casey Fossum | L | 25 | W 14-5 | @ TBA | 1 | 20 | W | 5.0 | 6 | 3 | 3 | 1 | 2 | 8 | 84 | 31 | 53 | 63% | 1-0 | 5.40 | 1.60 |
| 2003-04-04 | John Burkett | R | 38 | W 8-7 | @ BAL | 1 | 394 | W | 5.0 | 7 | 1 | 1 | 0 | 3 | 5 | 101 | 40 | 61 | 60% | 1-0 | 1.80 | 2.00 |
| 2003-04-05 | Pedro Martinez | R | 31 | L 1-2 | @ BAL | 2 | 261 | - | 8.0 | 4 | 1 | 1 | 0 | 0 | 6 | 92 | 29 | 63 | 68% | 0-0 | 0.60 | 0.53 |
| 2003-04-06 | Tim Wakefield | R | 37 | W 12-2 | @ BAL | 2 | 222 | W | 6.0 | 4 | 2 | 2 | 1 | 3 | 3 | 100 | 32 | 68 | 68% | 1-0 | 5.73 | 1.36 |
| 2003-04-08 | Derek Lowe | R | 30 | L 4-8 | @ TOR | 2 | 56 | L | 5.1 | 9 | 5 | 5 | 1 | 4 | 6 | 104 | 45 | 59 | 57% | 1-1 | 8.18 | 1.91 |
| 2003-04-09 | Casey Fossum | L | 25 | L 5-10 | @ TOR | 2 | 21 | L | 4.2 | 3 | 5 | 5 | 1 | 3 | 7 | 97 | 40 | 57 | 59% | 1-1 | 7.20 | 1.40 |
| 2003-04-10 | John Burkett | R | 38 | W 8-7 | @ TOR | 2 | 395 | - | 6.1 | 5 | 4 | 3 | 0 | 5 | 1 | 105 | 47 | 58 | 55% | 1-0 | 3.27 | 1.82 |
| 2003-04-12 | Pedro Martinez | R | 31 | W 6-13 | vs BAL | 3 | 262 | L | 4.1 | 9 | 10 | 10 | 0 | 4 | 5 | 92 | 39 | 53 | 58% | 0-1 | 5.21 | 1.11 |
| 2003-04-13 | Derek Lowe | R | 30 | L 2-0 | vs BAL | 3 | 57 | W | 7.0 | 5 | 0 | 0 | 0 | 1 | 3 | 96 | 39 | 57 | 59% | 2-1 | 5.00 | 1.50 |
| 2003-04-15 | Casey Fossum | L | 25 | L 6-5 | vs TBA | 3 | 22 | - | 7.0 | 6 | 1 | 1 | 1 | 0 | 4 | 94 | 27 | 67 | 71% | 1-1 | 4.76 | 1.18 |
| 2003-04-16 | John Burkett | R | 38 | L 6-4 | vs TBA | 3 | 396 | - | 6.2 | 6 | 4 | 3 | 1 | 2 | 4 | 104 | 37 | 67 | 64% | 1-0 | 3.50 | 1.56 |
| 2003-04-17 | Pedro Martinez | R | 31 | L 6-0 | vs TBA | 4 | 263 | W | 7.0 | 2 | 0 | 0 | 0 | 3 | 3 | 90 | 33 | 57 | 63% | 1-1 | 3.81 | 1.00 |
| 2003-04-18 | Tim Wakefield | R | 37 | L 7-3 | vs TOR | 3 | 223 | W | 7.0 | 7 | 3 | 2 | 0 | 3 | 6 | 105 | 41 | 64 | 61% | 2-0 | 4.05 | 1.35 |
| 2003-04-19 | Derek Lowe | R | 30 | L 7-2 | vs TOR | 4 | 58 | W | 5.0 | 7 | 2 | 0 | 0 | 3 | 5 | 103 | 44 | 59 | 57% | 3-1 | 3.91 | 1.61 |
| 2003-04-20 | Casey Fossum | L | 25 | L 6-5 | vs TOR | 4 | 23 | - | 6.0 | 6 | 5 | 4 | 0 | 5 | 3 | 99 | 40 | 59 | 60% | 1-1 | 5.09 | 1.35 |
| 2003-04-21 | John Burkett | R | 38 | W 6-11 | vs TOR | 4 | 397 | L | 2.2 | 8 | 7 | 7 | 1 | 1 | 2 | 68 | 26 | 42 | 62% | 1-1 | 6.00 | 1.76 |
| 2003-04-22 | Pedro Martinez | R | 31 | W 5-4 | @ TEX | 5 | 264 | W | 7.0 | 3 | 1 | 0 | 0 | 6 | 8 | 125 | 53 | 72 | 58% | 2-1 | 3.00 | 1.06 |
| 2003-04-23 | Tim Wakefield | R | 37 | L 1-6 | @ TEX | 4 | 224 | L | 5.1 | 7 | 4 | 4 | 1 | 3 | 5 | 90 | 37 | 53 | 59% | 2-1 | 4.68 | 1.48 |
| 2003-04-24 | Derek Lowe | R | 30 | L 5-16 | @ TEX | 5 | 59 | L | 2.0 | 6 | 7 | 7 | 1 | 3 | 2 | 62 | 28 | 34 | 55% | 3-2 | 6.12 | 1.84 |
| 2003-04-25 | Casey Fossum | L | 25 | W 5-2 | @ ANA | 5 | 24 | W | 7.0 | 5 | 0 | 0 | 0 | 1 | 5 | 106 | 32 | 74 | 70% | 2-1 | 3.90 | 1.23 |
| 2003-04-26 | John Burkett | R | 38 | L 1-3 | @ ANA | 5 | 398 | L | 8.0 | 9 | 3 | 3 | 0 | 1 | 5 | 100 | 31 | 69 | 69% | 1-2 | 5.28 | 1.62 |
| 2003-04-27 | Pedro Martinez | R | 32 | W 6-4 | @ ANA | 6 | 265 | - | 7.0 | 6 | 2 | 2 | 2 | 1 | 10 | 100 | 31 | 69 | 69% | 2-1 | 2.93 | 1.05 |
| 2003-04-29 | Tim Wakefield | R | 37 | L 7-2 | vs KCA | 5 | 225 | W | 6.0 | 7 | 2 | 2 | 2 | 1 | 6 | 104 | 36 | 68 | 65% | 3-1 | 4.35 | 1.45 |
| 2003-04-30 | Derek Lowe | R | 30 | L 5-4 | vs KCA | 6 | 60 | - | 7.0 | 2 | 2 | 2 | 0 | 3 | 2 | 96 | 34 | 62 | 65% | 3-2 | 5.34 | 1.59 |
| 2003-05-01 | Casey Fossum | L | 25 | L 6-5 | vs KCA | 6 | 25 | - | 0.2 | 2 | 2 | 2 | 1 | 0 | 1 | 12 | 3 | 9 | 75% | 2-1 | 4.50 | 1.30 |
| 2003-05-02 | John Burkett | R | 38 | W 7-11 | vs MIN | 6 | 399 | - | 6.1 | 7 | 5 | 5 | 2 | 3 | 4 | 85 | 38 | 47 | 55% | 1-2 | 5.66 | 1.63 |
| 2003-05-03 | Pedro Martinez | R | 32 | L 9-1 | vs MIN | 7 | 266 | W | 9.0 | 5 | 1 | 1 | 0 | 0 | 12 | 108 | 31 | 77 | 71% | 3-1 | 2.57 | 0.96 |
| 2003-05-04 | Tim Wakefield | R | 37 | W 4-9 | vs MIN | 6 | 226 | - | 5.2 | 8 | 4 | 4 | 0 | 3 | 4 | 85 | 29 | 56 | 66% | 3-1 | 4.62 | 1.51 |
| 2003-05-05 | Derek Lowe | R | 30 | L 6-7 | @ KCA | 7 | 61 | - | 3.2 | 7 | 5 | 4 | 2 | 3 | 3 | 80 | 29 | 51 | 64% | 3-2 | 5.75 | 1.69 |
| 2003-05-06 | Casey Fossum | L | 25 | W 7-3 | @ KCA | 7 | 26 | W | 6.2 | 5 | 3 | 3 | 0 | 5 | 2 | 108 | 47 | 61 | 56% | 3-1 | 4.38 | 1.32 |
| 2003-05-07 | John Burkett | R | 38 | W 9-6 | @ KCA | 7 | 400 | - | 5.2 | 6 | 6 | 6 | 0 | 1 | 6 | 82 | 31 | 51 | 62% | 1-2 | 6.15 | 1.56 |
| 2003-05-09 | Pedro Martinez | R | 32 | L 0-5 | @ MIN | 8 | 267 | L | 5.0 | 8 | 5 | 5 | 1 | 1 | 4 | 83 | 27 | 56 | 67% | 3-2 | 3.17 | 1.04 |
| 2003-05-10 | Tim Wakefield | R | 37 | W 6-5 | @ MIN | 7 | 227 | W | 7.0 | 7 | 4 | 4 | 2 | 2 | 6 | 99 | 31 | 68 | 69% | 4-1 | 4.60 | 1.47 |
| 2003-05-11 | Derek Lowe | R | 30 | L 8-9 | @ MIN | 8 | 62 | L | 4.0 | 10 | 8 | 6 | 0 | 0 | 3 | 75 | 25 | 50 | 67% | 3-3 | 6.53 | 1.78 |
| 2003-05-13 | John Burkett | R | 38 | L 5-4 | vs TEX | 8 | 401 | - | 7.0 | 6 | 4 | 4 | 2 | 3 | 2 | 100 | 39 | 61 | 61% | 1-2 | 6.00 | 1.52 |
| 2003-05-14 | Casey Fossum | L | 25 | L 7-1 | vs TEX | 8 | 27 | W | 5.0 | 4 | 1 | 1 | 0 | 1 | 4 | 84 | 27 | 57 | 68% | 4-1 | 4.07 | 1.29 |
| 2003-05-15 | Pedro Martinez | R | 32 | L 12-3 | vs TEX | 9 | 268 | W | 6.0 | 5 | 0 | 0 | 0 | 1 | 8 | 84 | 26 | 58 | 69% | 4-2 | 2.85 | 1.03 |
| 2003-05-16 | Tim Wakefield | R | 37 | W 5-6 | vs ANA | 8 | 228 | - | 6.0 | 6 | 4 | 3 | 0 | 2 | 6 | 98 | 33 | 65 | 66% | 4-1 | 4.59 | 1.45 |
| 2003-05-17 | Derek Lowe | R | 30 | W 2-6 | vs ANA | 9 | 63 | - | 7.1 | 7 | 2 | 2 | 0 | 3 | 3 | 100 | 38 | 62 | 62% | 3-3 | 5.94 | 1.72 |
| 2003-05-18 | John Burkett | R | 38 | L 5-3 | vs ANA | 9 | 402 | W | 7.0 | 7 | 1 | 1 | 0 | 0 | 4 | 90 | 27 | 63 | 70% | 2-2 | 5.40 | 1.45 |
| 2003-05-19 | Casey Fossum | L | 25 | W 3-7 | vs NYA | 9 | 28 | L | 6.0 | 6 | 5 | 5 | 0 | 2 | 4 | 107 | 42 | 65 | 61% | 4-2 | 4.50 | 1.29 |
| 2003-05-20 | Bruce Chen | L | 26 | L 10-7 | vs NYA | 1 | 60 | - | 4.0 | 4 | 3 | 2 | 1 | 1 | 2 | 66 | 24 | 42 | 64% | 0-0 | 5.21 | 1.58 |
| 2003-05-21 | Tim Wakefield | R | 37 | W 2-4 | vs NYA | 9 | 229 | L | 7.0 | 4 | 3 | 3 | 1 | 2 | 6 | 106 | 40 | 66 | 62% | 4-2 | 4.50 | 1.38 |
| 2003-05-23 | Derek Lowe | R | 30 | L 9-2 | vs CLE | 10 | 64 | W | 9.0 | 4 | 2 | 2 | 0 | 3 | 5 | 117 | 47 | 70 | 60% | 4-3 | 5.30 | 1.57 |
| 2003-05-24 | John Burkett | R | 38 | L 12-3 | vs CLE | 10 | 403 | W | 5.0 | 2 | 2 | 2 | 0 | 1 | 2 | 80 | 27 | 53 | 66% | 3-2 | 5.25 | 1.38 |
| 2003-05-25 | Casey Fossum | L | 25 | W 4-6 | vs CLE | 10 | 29 | L | 5.0 | 8 | 5 | 5 | 0 | 2 | 4 | 98 | 38 | 60 | 61% | 4-3 | 4.92 | 1.36 |
| 2003-05-26 | Tim Wakefield | R | 37 | W 8-4 | @ NYA | 10 | 230 | W | 5.0 | 4 | 3 | 3 | 0 | 6 | 4 | 103 | 44 | 59 | 57% | 5-2 | 4.57 | 1.43 |
| 2003-05-27 | Bruce Chen | L | 26 | L 3-11 | @ NYA | 2 | 61 | L | 5.0 | 5 | 4 | 4 | 3 | 1 | 3 | 78 | 27 | 51 | 65% | 0-1 | 5.63 | 1.50 |
| 2003-05-28 | Derek Lowe | R | 30 | L 5-6 | @ NYA | 11 | 65 | - | 6.0 | 8 | 4 | 4 | 0 | 2 | 3 | 102 | 39 | 63 | 62% | 4-3 | 5.37 | 1.58 |
| 2003-05-30 | John Burkett | R | 38 | L 2-13 | @ TOR | 11 | 404 | L | 2.0 | 8 | 8 | 8 | 2 | 0 | 0 | 51 | 19 | 32 | 63% | 3-3 | 6.24 | 1.47 |
| 2003-05-31 | Casey Fossum | L | 25 | L 7-10 | @ TOR | 11 | 30 | L | 5.1 | 9 | 9 | 9 | 2 | 2 | 5 | 93 | 30 | 63 | 68% | 4-4 | 5.90 | 1.43 |
| 2003-06-01 | Tim Wakefield | R | 37 | L 8-11 | @ TOR | 11 | 231 | - | 4.0 | 10 | 6 | 6 | 0 | 3 | 8 | 98 | 37 | 61 | 62% | 5-2 | 5.10 | 1.54 |
| 2003-06-04 | Byung-Hyun Kim | R | 24 | W 11-4 | @ PIT | 8 | 9 | W | 7.0 | 5 | 1 | 1 | 0 | 1 | 2 | 83 | 28 | 55 | 66% | 2-5 | 3.53 | 1.14 |
| 2003-06-04 | Derek Lowe | R | 30 | W 8-3 | @ PIT | 12 | 66 | W | 7.0 | 5 | 2 | 1 | 0 | 3 | 1 | 85 | 34 | 51 | 60% | 5-3 | 4.96 | 1.54 |
| 2003-06-05 | John Burkett | R | 39 | L 4-5 | @ PIT | 12 | 405 | - | 6.0 | 8 | 4 | 3 | 1 | 3 | 2 | 99 | 36 | 63 | 64% | 3-3 | 6.09 | 1.50 |
| 2003-06-06 | Tim Wakefield | R | 37 | L 3-9 | @ MIL | 12 | 232 | - | 2.0 | 3 | 3 | 3 | 2 | 0 | 4 | 28 | 8 | 20 | 71% | 5-2 | 5.35 | 1.54 |
| 2003-06-07 | Casey Fossum | L | 25 | W 11-10 | @ MIL | 12 | 31 | - | 1.0 | 1 | 2 | 0 | 0 | 1 | 3 | 30 | 13 | 17 | 57% | 4-4 | 5.80 | 1.44 |
| 2003-06-08 | Derek Lowe | R | 30 | W 9-1 | @ MIL | 13 | 67 | W | 6.0 | 5 | 1 | 1 | 0 | 1 | 5 | 73 | 32 | 41 | 56% | 6-3 | 4.68 | 1.49 |
| 2003-06-10 | Byung-Hyun Kim | R | 24 | W 7-9 | vs SLN | 9 | 10 | - | 5.0 | 6 | 4 | 4 | 1 | 0 | 2 | 87 | 30 | 57 | 66% | 2-5 | 4.34 | 1.19 |
| 2003-06-11 | Pedro Martinez | R | 32 | L 13-1 | vs SLN | 10 | 269 | - | 3.0 | 2 | 0 | 0 | 0 | 0 | 3 | 47 | 14 | 33 | 70% | 4-2 | 2.71 | 1.02 |
| 2003-06-12 | Tim Wakefield | R | 37 | W 7-8 | vs SLN | 13 | 233 | - | 6.0 | 6 | 2 | 1 | 0 | 2 | 4 | 92 | 28 | 64 | 70% | 5-2 | 5.04 | 1.52 |
| 2003-06-13 | Ryan Rupe | R | 28 | L 4-3 | vs HOU | 1 | 84 | W | 6.0 | 8 | 3 | 1 | 1 | 0 | 4 | 106 | 37 | 69 | 65% | 1-0 | 1.50 | 1.33 |
| 2003-06-14 | Derek Lowe | R | 30 | L 8-4 | vs HOU | 14 | 68 | W | 7.1 | 9 | 4 | 4 | 2 | 1 | 1 | 112 | 34 | 78 | 70% | 7-3 | 4.66 | 1.47 |
| 2003-06-15 | Byung-Hyun Kim | R | 24 | L 3-2 | vs HOU | 10 | 11 | - | 6.0 | 7 | 2 | 2 | 1 | 2 | 4 | 93 | 26 | 67 | 72% | 2-5 | 4.22 | 1.22 |
| 2003-06-16 | Pedro Martinez | R | 32 | L 2-4 | @ CHA | 11 | 270 | - | 5.0 | 6 | 1 | 1 | 0 | 1 | 6 | 71 | 22 | 49 | 69% | 4-2 | 2.65 | 1.04 |
| 2003-06-17 | John Burkett | R | 39 | W 7-4 | @ CHA | 13 | 406 | W | 6.2 | 5 | 3 | 3 | 0 | 1 | 9 | 109 | 38 | 71 | 65% | 5-3 | 5.63 | 1.46 |
| 2003-06-18 | Tim Wakefield | R | 37 | L 1-3 | @ CHA | 14 | 234 | L | 7.0 | 3 | 2 | 2 | 0 | 5 | 8 | 111 | 47 | 64 | 58% | 5-3 | 4.83 | 1.49 |
| 2003-06-19 | Derek Lowe | R | 30 | W 4-3 | @ CHA | 15 | 69 | - | 6.0 | 7 | 3 | 2 | 0 | 3 | 2 | 100 | 37 | 63 | 63% | 7-3 | 4.55 | 1.48 |
| 2003-06-21 | Pedro Martinez | R | 32 | L 5-6 | @ PHI | 12 | 271 | - | 7.0 | 4 | 1 | 1 | 1 | 2 | 7 | 94 | 28 | 66 | 70% | 4-2 | 2.52 | 1.03 |
| 2003-06-22 | Byung-Hyun Kim | R | 24 | L 0-5 | @ PHI | 11 | 12 | L | 6.0 | 4 | 2 | 2 | 1 | 3 | 3 | 101 | 33 | 68 | 67% | 2-6 | 4.11 | 1.21 |
| 2003-06-23 | Tim Wakefield | R | 37 | L 3-1 | vs DET | 15 | 235 | W | 6.0 | 4 | 0 | 0 | 0 | 2 | 5 | 90 | 26 | 64 | 71% | 6-3 | 4.50 | 1.45 |
| 2003-06-24 | Derek Lowe | R | 30 | L 10-1 | vs DET | 16 | 70 | W | 8.0 | 7 | 1 | 1 | 0 | 2 | 4 | 110 | 42 | 68 | 62% | 8-3 | 4.27 | 1.45 |
| 2003-06-25 | John Burkett | R | 39 | L 11-2 | vs DET | 14 | 407 | W | 6.0 | 4 | 1 | 1 | 0 | 2 | 5 | 94 | 37 | 57 | 61% | 6-3 | 5.34 | 1.43 |
| 2003-06-26 | Pedro Martinez | R | 32 | L 6-4 | vs DET | 13 | 272 | W | 6.2 | 7 | 4 | 4 | 0 | 3 | 8 | 110 | 43 | 67 | 61% | 5-2 | 2.74 | 1.06 |
| 2003-06-27 | Byung-Hyun Kim | R | 24 | L 25-8 | vs FLO | 12 | 13 | W | 5.0 | 7 | 5 | 1 | 0 | 2 | 4 | 87 | 29 | 58 | 67% | 3-6 | 3.96 | 1.25 |
| 2003-06-28 | Tim Wakefield | R | 37 | W 9-10 | vs FLO | 16 | 236 | - | 7.1 | 9 | 6 | 6 | 1 | 2 | 2 | 93 | 27 | 66 | 71% | 6-3 | 4.74 | 1.46 |
| 2003-06-29 | Derek Lowe | R | 30 | L 11-7 | vs FLO | 17 | 71 | W | 7.0 | 5 | 6 | 6 | 1 | 2 | 7 | 97 | 35 | 62 | 64% | 9-3 | 4.50 | 1.42 |
| 2003-07-01 | John Burkett | R | 39 | L 3-4 | @ TBA | 15 | 408 | - | 6.0 | 6 | 3 | 3 | 0 | 2 | 6 | 118 | 44 | 74 | 63% | 6-3 | 5.28 | 1.42 |
| 2003-07-02 | Pedro Martinez | R | 32 | W 5-4 | @ TBA | 14 | 273 | W | 7.0 | 6 | 3 | 0 | 1 | 2 | 7 | 98 | 37 | 61 | 62% | 6-2 | 2.53 | 1.07 |
| 2003-07-03 | Tim Wakefield | R | 37 | L 5-6 | @ TBA | 17 | 237 | - | 6.2 | 4 | 3 | 0 | 0 | 3 | 6 | 104 | 39 | 65 | 63% | 6-3 | 4.41 | 1.43 |
| 2003-07-04 | Derek Lowe | R | 30 | W 10-3 | @ NYA | 18 | 72 | W | 6.1 | 10 | 3 | 3 | 2 | 1 | 2 | 116 | 40 | 76 | 66% | 10-3 | 4.50 | 1.45 |
| 2003-07-05 | Ramiro Mendoza | R | 31 | W 10-2 | @ NYA | 1 | 58 | W | 5.0 | 6 | 0 | 0 | 0 | 2 | 1 | 73 | 32 | 41 | 56% | 2-3 | 6.07 | 1.91 |
| 2003-07-06 | John Burkett | R | 39 | L 1-7 | @ NYA | 16 | 409 | L | 5.1 | 10 | 4 | 4 | 1 | 3 | 3 | 101 | 41 | 60 | 59% | 6-4 | 5.33 | 1.47 |
| 2003-07-07 | Pedro Martinez | R | 32 | L 1-2 | @ NYA | 15 | 274 | - | 7.0 | 5 | 1 | 1 | 0 | 0 | 11 | 115 | 36 | 79 | 69% | 6-2 | 2.44 | 1.04 |
| 2003-07-08 | Tim Wakefield | R | 37 | W 2-1 | @ TOR | 18 | 238 | - | 7.0 | 6 | 1 | 1 | 0 | 0 | 7 | 96 | 31 | 65 | 68% | 6-3 | 4.21 | 1.39 |
| 2003-07-09 | Derek Lowe | R | 30 | W 8-7 | @ TOR | 19 | 73 | - | 6.0 | 11 | 7 | 7 | 1 | 2 | 3 | 105 | 37 | 68 | 65% | 10-3 | 4.81 | 1.48 |
| 2003-07-10 | Ramiro Mendoza | R | 31 | W 7-1 | @ TOR | 2 | 59 | W | 5.0 | 5 | 1 | 1 | 1 | 1 | 4 | 90 | 30 | 60 | 67% | 3-3 | 5.63 | 1.83 |
| 2003-07-11 | John Burkett | R | 39 | W 5-3 | @ DET | 17 | 410 | W | 7.0 | 4 | 3 | 3 | 1 | 1 | 4 | 78 | 29 | 49 | 63% | 7-4 | 5.23 | 1.42 |
| 2003-07-12 | Pedro Martinez | R | 32 | W 4-2 | @ DET | 16 | 275 | - | 7.0 | 4 | 1 | 1 | 0 | 1 | 8 | 109 | 38 | 71 | 65% | 6-2 | 2.36 | 1.02 |
| 2003-07-13 | Tim Wakefield | R | 37 | L 0-3 | @ DET | 19 | 239 | L | 7.1 | 4 | 3 | 2 | 1 | 2 | 5 | 109 | 35 | 74 | 68% | 6-4 | 4.11 | 1.36 |
| 2003-07-17 | Derek Lowe | R | 30 | W 2-5 | vs TOR | 20 | 74 | L | 4.0 | 7 | 4 | 4 | 0 | 1 | 4 | 91 | 35 | 56 | 62% | 10-4 | 4.95 | 1.50 |
| 2003-07-18 | Tim Wakefield | R | 37 | W 1-4 | vs TOR | 20 | 240 | L | 7.0 | 7 | 4 | 4 | 1 | 3 | 7 | 118 | 47 | 71 | 60% | 6-5 | 4.17 | 1.37 |
| 2003-07-19 | Ramiro Mendoza | R | 31 | L 5-4 | vs TOR | 3 | 60 | - | 5.2 | 5 | 4 | 4 | 0 | 3 | 3 | 83 | 37 | 46 | 55% | 3-3 | 5.67 | 1.78 |
| 2003-07-20 | Pedro Martinez | R | 32 | L 9-4 | vs TOR | 17 | 276 | W | 7.0 | 3 | 0 | 0 | 0 | 0 | 8 | 87 | 23 | 64 | 74% | 7-2 | 2.21 | 0.98 |
| 2003-07-21 | John Burkett | R | 39 | L 14-5 | vs DET | 18 | 411 | W | 5.0 | 8 | 3 | 3 | 0 | 1 | 4 | 80 | 26 | 54 | 68% | 8-4 | 5.24 | 1.44 |
| 2003-07-22 | Derek Lowe | R | 30 | L 7-4 | vs DET | 21 | 75 | W | 8.0 | 6 | 3 | 3 | 2 | 0 | 4 | 85 | 26 | 59 | 69% | 11-4 | 4.85 | 1.45 |
| 2003-07-23 | Tim Wakefield | R | 37 | L 10-4 | vs TBA | 21 | 241 | W | 7.0 | 6 | 4 | 4 | 2 | 1 | 5 | 89 | 20 | 69 | 78% | 7-5 | 4.22 | 1.35 |
| 2003-07-24 | Ramiro Mendoza | R | 31 | W 9-15 | vs TBA | 4 | 61 | L | 4.1 | 9 | 7 | 7 | 1 | 0 | 1 | 61 | 17 | 44 | 72% | 3-4 | 6.36 | 1.81 |
| 2003-07-25 | Pedro Martinez | R | 32 | W 3-4 | vs NYA | 18 | 277 | - | 6.2 | 7 | 3 | 3 | 1 | 4 | 10 | 127 | 50 | 77 | 61% | 7-2 | 2.31 | 1.02 |
| 2003-07-26 | John Burkett | R | 39 | L 5-4 | vs NYA | 19 | 412 | - | 5.2 | 3 | 0 | 0 | 0 | 3 | 3 | 79 | 30 | 49 | 62% | 8-4 | 5.01 | 1.43 |
| 2003-07-27 | Derek Lowe | R | 30 | L 6-4 | vs NYA | 22 | 76 | - | 6.0 | 9 | 3 | 3 | 1 | 3 | 3 | 89 | 41 | 48 | 54% | 11-4 | 4.84 | 1.48 |
| 2003-07-29 | Tim Wakefield | R | 37 | W 14-7 | @ TEX | 22 | 242 | W | 6.0 | 6 | 4 | 2 | 1 | 2 | 8 | 105 | 44 | 61 | 58% | 8-5 | 4.17 | 1.35 |
| 2003-07-30 | Ramiro Mendoza | R | 31 | L 2-9 | @ TEX | 5 | 62 | L | 4.1 | 7 | 7 | 7 | 3 | 1 | 5 | 86 | 29 | 57 | 66% | 3-5 | 6.86 | 1.79 |
| 2003-07-31 | Pedro Martinez | R | 32 | L 3-7 | @ TEX | 19 | 278 | - | 6.0 | 6 | 3 | 3 | 0 | 3 | 7 | 110 | 43 | 67 | 61% | 7-2 | 2.41 | 1.04 |
| 2003-08-01 | John Burkett | R | 39 | L 1-2 | @ BAL | 20 | 413 | L | 7.0 | 8 | 2 | 2 | 0 | 2 | 0 | 103 | 47 | 56 | 54% | 8-5 | 4.87 | 1.43 |
| 2003-08-02 | Derek Lowe | R | 30 | L 2-11 | @ BAL | 23 | 77 | L | 5.2 | 8 | 6 | 5 | 0 | 3 | 4 | 96 | 38 | 58 | 60% | 11-5 | 4.95 | 1.49 |
| 2003-08-03 | Tim Wakefield | R | 37 | W 7-5 | @ BAL | 23 | 243 | W | 5.2 | 4 | 3 | 3 | 1 | 1 | 5 | 90 | 28 | 62 | 69% | 9-5 | 4.18 | 1.32 |
| 2003-08-05 | Jeff Suppan | R | 29 | L 10-9 | vs ANA | 22 | 197 | - | 5.0 | 7 | 7 | 7 | 3 | 1 | 4 | 103 | 41 | 62 | 60% | 10-7 | 3.88 | 1.27 |
| 2003-08-06 | Pedro Martinez | R | 32 | L 4-2 | vs ANA | 20 | 279 | W | 9.0 | 10 | 2 | 1 | 0 | 1 | 11 | 126 | 37 | 89 | 71% | 8-2 | 2.32 | 1.05 |
| 2003-08-07 | John Burkett | R | 39 | L 9-3 | vs ANA | 21 | 414 | W | 7.0 | 6 | 3 | 3 | 2 | 0 | 2 | 97 | 35 | 62 | 64% | 9-5 | 4.81 | 1.40 |
| 2003-08-08 | Derek Lowe | R | 30 | W 4-10 | vs BAL | 24 | 78 | L | 6.0 | 8 | 6 | 5 | 0 | 1 | 3 | 81 | 24 | 57 | 70% | 11-6 | 5.05 | 1.49 |
| 2003-08-08 | Casey Fossum | L | 26 | W 2-4 | vs BAL | 13 | 32 | L | 5.1 | 6 | 4 | 0 | 0 | 1 | 3 | 99 | 33 | 66 | 67% | 5-5 | 5.13 | 1.40 |
| 2003-08-09 | Tim Wakefield | R | 37 | L 6-4 | vs BAL | 24 | 244 | - | 7.2 | 5 | 3 | 3 | 1 | 1 | 5 | 92 | 30 | 62 | 67% | 9-5 | 4.14 | 1.29 |
| 2003-08-10 | Jeff Suppan | R | 29 | W 3-5 | vs BAL | 23 | 198 | L | 6.1 | 6 | 5 | 5 | 1 | 2 | 4 | 97 | 35 | 62 | 64% | 10-8 | 4.03 | 1.28 |
| 2003-08-11 | Pedro Martinez | R | 32 | L 0-4 | @ OAK | 21 | 280 | L | 5.0 | 5 | 2 | 2 | 0 | 2 | 7 | 100 | 38 | 62 | 62% | 8-3 | 2.36 | 1.07 |
| 2003-08-12 | John Burkett | R | 39 | L 3-5 | @ OAK | 22 | 415 | L | 6.0 | 7 | 5 | 5 | 2 | 0 | 3 | 92 | 33 | 59 | 64% | 9-6 | 4.93 | 1.39 |
| 2003-08-13 | Derek Lowe | R | 30 | W 7-3 | @ OAK | 25 | 79 | W | 5.0 | 5 | 2 | 2 | 0 | 2 | 3 | 91 | 39 | 52 | 57% | 12-6 | 5.01 | 1.49 |
| 2003-08-14 | Tim Wakefield | R | 37 | W 4-2 | @ OAK | 25 | 245 | - | 6.0 | 5 | 2 | 2 | 0 | 4 | 8 | 112 | 45 | 67 | 60% | 9-5 | 4.10 | 1.30 |
| 2003-08-15 | Jeff Suppan | R | 29 | L 5-10 | @ SEA | 24 | 199 | - | 5.0 | 7 | 4 | 4 | 1 | 2 | 3 | 88 | 32 | 56 | 64% | 10-8 | 4.13 | 1.29 |
| 2003-08-16 | Pedro Martinez | R | 32 | W 5-1 | @ SEA | 22 | 281 | W | 7.0 | 3 | 1 | 1 | 0 | 3 | 7 | 106 | 39 | 67 | 63% | 9-3 | 2.31 | 1.06 |
| 2003-08-17 | John Burkett | R | 39 | L 1-3 | @ SEA | 23 | 416 | L | 6.2 | 6 | 3 | 3 | 0 | 1 | 6 | 116 | 44 | 72 | 62% | 9-7 | 4.88 | 1.37 |
| 2003-08-19 | Derek Lowe | R | 30 | W 2-3 | vs OAK | 26 | 80 | - | 6.0 | 2 | 0 | 0 | 0 | 0 | 3 | 78 | 28 | 50 | 64% | 12-6 | 4.82 | 1.45 |
| 2003-08-20 | Tim Wakefield | R | 37 | W 6-8 | vs OAK | 26 | 246 | - | 6.0 | 7 | 4 | 4 | 2 | 1 | 4 | 102 | 36 | 66 | 65% | 9-5 | 4.17 | 1.30 |
| 2003-08-21 | Casey Fossum | L | 26 | L 14-5 | vs OAK | 14 | 33 | W | 5.1 | 8 | 5 | 5 | 0 | 3 | 2 | 96 | 39 | 57 | 59% | 6-5 | 5.54 | 1.46 |
| 2003-08-22 | Jeff Suppan | R | 29 | L 6-4 | vs SEA | 25 | 200 | W | 6.2 | 6 | 2 | 2 | 0 | 0 | 1 | 89 | 27 | 62 | 70% | 11-8 | 4.06 | 1.27 |
| 2003-08-23 | John Burkett | R | 39 | L 7-6 | vs SEA | 24 | 417 | - | 6.0 | 8 | 5 | 5 | 0 | 1 | 5 | 85 | 28 | 57 | 67% | 9-7 | 4.99 | 1.37 |
| 2003-08-24 | Derek Lowe | R | 30 | L 6-1 | vs SEA | 27 | 81 | W | 7.1 | 5 | 1 | 1 | 0 | 5 | 4 | 107 | 43 | 64 | 60% | 13-6 | 4.66 | 1.45 |
| 2003-08-25 | Pedro Martinez | R | 32 | L 8-1 | vs SEA | 23 | 282 | W | 6.0 | 6 | 1 | 1 | 0 | 2 | 4 | 87 | 34 | 53 | 61% | 10-3 | 2.28 | 1.07 |
| 2003-08-26 | Tim Wakefield | R | 37 | W 9-12 | vs TOR | 27 | 247 | - | 3.1 | 9 | 7 | 5 | 1 | 2 | 1 | 68 | 24 | 44 | 65% | 9-5 | 4.36 | 1.35 |
| 2003-08-27 | John Burkett | R | 39 | L 6-3 | vs TOR | 25 | 418 | - | 6.0 | 7 | 3 | 3 | 1 | 2 | 1 | 98 | 31 | 67 | 68% | 9-7 | 4.97 | 1.38 |
| 2003-08-29 | Derek Lowe | R | 30 | L 10-5 | vs NYA | 28 | 82 | W | 6.0 | 5 | 5 | 5 | 0 | 3 | 1 | 97 | 41 | 56 | 58% | 14-6 | 4.76 | 1.44 |
| 2003-08-30 | Pedro Martinez | R | 32 | W 7-10 | vs NYA | 24 | 283 | L | 4.0 | 9 | 5 | 5 | 1 | 0 | 3 | 87 | 29 | 58 | 67% | 10-4 | 2.51 | 1.10 |
| 2003-08-31 | Tim Wakefield | R | 37 | W 4-8 | vs NYA | 28 | 248 | L | 6.0 | 8 | 6 | 5 | 0 | 2 | 5 | 97 | 32 | 65 | 67% | 9-6 | 4.47 | 1.36 |
| 2003-09-01 | Jeff Suppan | R | 29 | W 13-9 | @ PHI | 26 | 201 | - | 6.0 | 10 | 6 | 5 | 1 | 3 | 2 | 88 | 34 | 54 | 61% | 11-8 | 4.09 | 1.30 |
| 2003-09-02 | John Burkett | R | 39 | W 2-1 | @ CHA | 26 | 419 | W | 6.0 | 3 | 1 | 1 | 0 | 1 | 4 | 116 | 44 | 72 | 62% | 10-7 | 4.84 | 1.35 |
| 2003-09-03 | Derek Lowe | R | 30 | W 5-4 | @ CHA | 29 | 83 | - | 7.0 | 10 | 3 | 3 | 0 | 4 | 3 | 103 | 42 | 61 | 59% | 14-6 | 4.73 | 1.46 |
| 2003-09-05 | Pedro Martinez | R | 32 | W 9-3 | @ NYA | 25 | 284 | W | 6.0 | 4 | 1 | 1 | 0 | 1 | 9 | 94 | 33 | 61 | 65% | 11-4 | 2.48 | 1.09 |
| 2003-09-06 | Tim Wakefield | R | 37 | W 11-0 | @ NYA | 29 | 249 | W | 7.0 | 4 | 0 | 0 | 0 | 3 | 2 | 102 | 42 | 60 | 59% | 10-6 | 4.30 | 1.34 |
| 2003-09-07 | Jeff Suppan | R | 29 | L 1-3 | @ NYA | 27 | 202 | L | 7.0 | 3 | 2 | 2 | 1 | 2 | 3 | 101 | 39 | 62 | 61% | 11-9 | 4.03 | 1.28 |
| 2003-09-08 | John Burkett | R | 39 | L 10-13 | @ BAL | 27 | 420 | - | 5.1 | 10 | 5 | 5 | 0 | 0 | 0 | 94 | 35 | 59 | 63% | 10-7 | 4.96 | 1.37 |
| 2003-09-09 | Derek Lowe | R | 30 | W 9-2 | @ BAL | 30 | 84 | W | 6.0 | 6 | 1 | 1 | 0 | 2 | 5 | 113 | 48 | 65 | 58% | 15-6 | 4.62 | 1.46 |
| 2003-09-10 | Pedro Martinez | R | 32 | W 5-0 | @ BAL | 26 | 285 | W | 8.0 | 3 | 0 | 0 | 0 | 2 | 9 | 116 | 37 | 79 | 68% | 12-4 | 2.36 | 1.07 |
| 2003-09-12 | Jeff Suppan | R | 29 | L 7-4 | vs CHA | 28 | 203 | W | 6.0 | 5 | 3 | 3 | 2 | 3 | 2 | 102 | 42 | 60 | 59% | 12-9 | 4.04 | 1.28 |
| 2003-09-13 | Tim Wakefield | R | 37 | W 1-3 | vs CHA | 30 | 250 | L | 7.0 | 6 | 3 | 3 | 1 | 2 | 8 | 112 | 39 | 73 | 65% | 10-7 | 4.28 | 1.34 |
| 2003-09-14 | John Burkett | R | 39 | W 2-7 | vs CHA | 28 | 421 | L | 6.0 | 6 | 5 | 5 | 2 | 2 | 4 | 109 | 46 | 63 | 58% | 10-8 | 5.05 | 1.37 |
| 2003-09-15 | Derek Lowe | R | 30 | L 8-2 | vs TBA | 31 | 85 | W | 8.0 | 4 | 2 | 2 | 1 | 2 | 6 | 118 | 42 | 76 | 64% | 16-6 | 4.52 | 1.43 |
| 2003-09-16 | Pedro Martinez | R | 32 | L 3-2 | vs TBA | 27 | 286 | W | 9.0 | 6 | 2 | 2 | 0 | 1 | 6 | 121 | 37 | 84 | 69% | 13-4 | 2.34 | 1.05 |
| 2003-09-17 | Jeff Suppan | R | 29 | W 0-7 | vs TBA | 29 | 204 | L | 5.1 | 10 | 5 | 4 | 1 | 3 | 5 | 108 | 45 | 63 | 58% | 12-10 | 4.13 | 1.32 |
| 2003-09-18 | Tim Wakefield | R | 37 | L 4-3 | vs TBA | 31 | 251 | W | 8.1 | 7 | 3 | 1 | 0 | 1 | 4 | 119 | 33 | 86 | 72% | 11-7 | 4.15 | 1.32 |
| 2003-09-19 | John Burkett | R | 39 | W 2-0 | @ CLE | 29 | 422 | W | 7.0 | 3 | 0 | 0 | 0 | 1 | 3 | 97 | 36 | 61 | 63% | 11-8 | 4.85 | 1.34 |
| 2003-09-20 | Derek Lowe | R | 30 | L 4-13 | @ CLE | 32 | 86 | L | 6.1 | 9 | 6 | 4 | 2 | 0 | 3 | 85 | 25 | 60 | 71% | 16-7 | 4.57 | 1.43 |
| 2003-09-21 | Pedro Martinez | R | 32 | W 2-0 | @ CLE | 28 | 287 | W | 7.0 | 4 | 0 | 0 | 0 | 2 | 11 | 115 | 41 | 74 | 64% | 14-4 | 2.25 | 1.04 |
| 2003-09-22 | Jeff Suppan | R | 29 | L 7-5 | vs BAL | 30 | 205 | W | 6.0 | 6 | 2 | 2 | 1 | 1 | 3 | 97 | 37 | 60 | 62% | 13-10 | 4.09 | 1.31 |
| 2003-09-23 | Tim Wakefield | R | 37 | L 6-5 | vs BAL | 32 | 252 | - | 7.0 | 7 | 3 | 3 | 1 | 0 | 4 | 98 | 31 | 67 | 68% | 11-7 | 4.14 | 1.31 |
| 2003-09-24 | John Burkett | R | 39 | W 3-7 | vs BAL | 30 | 423 | L | 0.1 | 7 | 7 | 6 | 1 | 0 | 1 | 28 | 7 | 21 | 75% | 11-9 | 5.13 | 1.37 |
| 2003-09-25 | Derek Lowe | R | 30 | L 14-3 | vs BAL | 33 | 87 | W | 6.0 | 2 | 2 | 1 | 0 | 4 | 1 | 94 | 38 | 56 | 60% | 17-7 | 4.48 | 1.42 |
| 2003-09-26 | Pedro Martinez | R | 32 | W 7-2 | @ TBA | 29 | 288 | - | 3.0 | 2 | 0 | 0 | 0 | 0 | 2 | 51 | 18 | 33 | 65% | 14-4 | 2.21 | 1.04 |
| 2003-09-27 | Jeff Suppan | R | 29 | L 4-5 | @ TBA | 31 | 206 | L | 6.0 | 8 | 5 | 5 | 1 | 0 | 3 | 97 | 36 | 61 | 63% | 13-11 | 4.19 | 1.31 |
| 2003-09-28 | Tim Wakefield | R | 37 | L 1-3 | @ TBA | 33 | 253 | - | 2.0 | 2 | 0 | 0 | 0 | 0 | 1 | 23 | 8 | 15 | 65% | 11-7 | 4.10 | 1.31 |