| 2003-03-31 | @ TBA | 1 | L 4-6 | 0-1 | 4 | 34,391 | Pedro Martinez | Joe Kennedy | Seth McClung | Chad Fox | | 4 | 6 | -2 |
| 2003-04-01 | @ TBA | 2 | W 9-8 | 1-1 | 3 | 11,524 | Tim Wakefield | Victor Zambrano | Brandon Lyon | Jorge Sosa | | 13 | 14 | -1 |
| 2003-04-02 | @ TBA | 3 | W 7-5 | 2-1 | 2 | 10,058 | Derek Lowe | Jim Parque | Derek Lowe | Jim Parque | Chad Fox | 20 | 19 | 1 |
| 2003-04-03 | @ TBA | 4 | W 14-5 | 3-1 | 2 | 12,110 | Casey Fossum | Nick Bierbrodt | Casey Fossum | Nick Bierbrodt | | 34 | 24 | 10 |
| 2003-04-04 | @ BAL | 5 | W 8-7 | 4-1 | 2 | 27,256 | John Burkett | Sidney Ponson | John Burkett | Sidney Ponson | | 42 | 31 | 11 |
| 2003-04-05 | @ BAL | 6 | L 1-2 | 4-2 | 2 | 41,821 | Pedro Martinez | Jason Johnson | B.J. Ryan | Chad Fox | | 43 | 33 | 10 |
| 2003-04-06 | @ BAL | 7 | W 12-2 | 5-2 | 2 | 30,046 | Tim Wakefield | Rodrigo Lopez | Tim Wakefield | Rodrigo Lopez | | 55 | 35 | 20 |
| 2003-04-08 | @ TOR | 8 | L 4-8 | 5-3 | 2 | 13,147 | Derek Lowe | Mark Hendrickson | Mark Hendrickson | Derek Lowe | | 59 | 43 | 16 |
| 2003-04-09 | @ TOR | 9 | L 5-10 | 5-4 | 3 | 13,099 | Casey Fossum | Tanyon Sturtze | Tanyon Sturtze | Casey Fossum | | 64 | 53 | 11 |
| 2003-04-10 | @ TOR | 10 | W 8-7 | 6-4 | 2 | 13,779 | John Burkett | Roy Halladay | Mike Timlin | Cliff Politte | | 72 | 60 | 12 |
| 2003-04-12 | vs BAL | 11 | L 6-13 | 6-5 | 2 | 32,029 | Pedro Martinez | Jason Johnson | Jason Johnson | Pedro Martinez | | 78 | 73 | 5 |
| 2003-04-13 | vs BAL | 12 | W 2-0 | 7-5 | 2 | 32,368 | Derek Lowe | Rodrigo Lopez | Derek Lowe | Rodrigo Lopez | Tim Wakefield | 80 | 73 | 7 |
| 2003-04-15 | vs TBA | 13 | W 6-5 | 8-5 | 2 | 29,617 | Casey Fossum | Nick Bierbrodt | Mike Timlin | Al Levine | | 86 | 78 | 8 |
| 2003-04-16 | vs TBA | 14 | W 6-4 | 9-5 | 2 | 26,688 | John Burkett | Steve Parris | Chad Fox | Lance Carter | Brandon Lyon | 92 | 82 | 10 |
| 2003-04-17 | vs TBA | 15 | W 6-0 | 10-5 | 2 | 30,909 | Pedro Martinez | Joe Kennedy | Pedro Martinez | Joe Kennedy | | 98 | 82 | 16 |
| 2003-04-18 | vs TOR | 16 | W 7-3 | 11-5 | 2 | 31,440 | Tim Wakefield | Mark Hendrickson | Tim Wakefield | Jeff Tam | | 105 | 85 | 20 |
| 2003-04-19 | vs TOR | 17 | W 7-2 | 12-5 | 2 | 32,329 | Derek Lowe | Tanyon Sturtze | Derek Lowe | Tanyon Sturtze | | 112 | 87 | 25 |
| 2003-04-20 | vs TOR | 18 | W 6-5 | 13-5 | 2 | 29,579 | Casey Fossum | Roy Halladay | Mike Timlin | Cliff Politte | | 118 | 92 | 26 |
| 2003-04-21 | vs TOR | 19 | L 6-11 | 13-6 | 2 | 34,370 | John Burkett | Cory Lidle | Cory Lidle | John Burkett | | 124 | 103 | 21 |
| 2003-04-22 | @ TEX | 20 | W 5-4 | 14-6 | 2 | 20,158 | Pedro Martinez | Chan Ho Park | Pedro Martinez | Chan Ho Park | Chad Fox | 129 | 107 | 22 |
| 2003-04-23 | @ TEX | 21 | L 1-6 | 14-7 | 2 | 20,042 | Tim Wakefield | John Thomson | John Thomson | Tim Wakefield | | 130 | 113 | 17 |
| 2003-04-24 | @ TEX | 22 | L 5-16 | 14-8 | 2 | 21,063 | Derek Lowe | Ryan Drese | R.A. Dickey | Derek Lowe | | 135 | 129 | 6 |
| 2003-04-25 | @ ANA | 23 | W 5-2 | 15-8 | 2 | 37,203 | Casey Fossum | Jarrod Washburn | Casey Fossum | Jarrod Washburn | Chad Fox | 140 | 131 | 9 |
| 2003-04-26 | @ ANA | 24 | L 1-3 | 15-9 | 2 | 43,514 | John Burkett | Scot Shields | Scot Shields | John Burkett | Troy Percival | 141 | 134 | 7 |
| 2003-04-27 | @ ANA | 25 | W 6-4 | 16-9 | 2 | 43,690 | Pedro Martinez | John Lackey | Ramiro Mendoza | Mickey Callaway | Jason Shiell | 147 | 138 | 9 |
| 2003-04-29 | vs KCA | 26 | W 7-2 | 17-9 | 2 | 30,438 | Tim Wakefield | Chris George | Tim Wakefield | Chris George | | 154 | 140 | 14 |
| 2003-04-30 | vs KCA | 27 | W 5-4 | 18-9 | 2 | 31,334 | Derek Lowe | Darrell May | Alan Embree | Mike MacDougal | | 159 | 144 | 15 |
| 2003-05-01 | vs KCA | 28 | W 6-5 | 19-9 | 2 | 31,950 | Casey Fossum | Kyle Snyder | Jason Shiell | Jason Grimsley | Brandon Lyon | 165 | 149 | 16 |
| 2003-05-02 | vs MIN | 29 | L 7-11 | 19-10 | 2 | 31,317 | John Burkett | Kyle Lohse | Johan Santana | Ramiro Mendoza | | 172 | 160 | 12 |
| 2003-05-03 | vs MIN | 30 | W 9-1 | 20-10 | 2 | 33,061 | Pedro Martinez | Rick Reed | Pedro Martinez | Tony Fiore | | 181 | 161 | 20 |
| 2003-05-04 | vs MIN | 31 | L 4-9 | 20-11 | 2 | 32,887 | Tim Wakefield | Kenny Rogers | Kenny Rogers | Mike Timlin | | 185 | 170 | 15 |
| 2003-05-05 | @ KCA | 32 | L 6-7 | 20-12 | 2 | 21,232 | Derek Lowe | Darrell May | Albie Lopez | Brandon Lyon | | 191 | 177 | 14 |
| 2003-05-06 | @ KCA | 33 | W 7-3 | 21-12 | 2 | 15,848 | Casey Fossum | Jeremy Affeldt | Casey Fossum | Jeremy Affeldt | | 198 | 180 | 18 |
| 2003-05-07 | @ KCA | 34 | W 9-6 | 22-12 | 2 | 28,268 | John Burkett | Kyle Snyder | Steve Woodard | Albie Lopez | Brandon Lyon | 207 | 186 | 21 |
| 2003-05-09 | @ MIN | 35 | L 0-5 | 22-13 | 2 | 28,436 | Pedro Martinez | Johan Santana | Johan Santana | Pedro Martinez | | 207 | 191 | 16 |
| 2003-05-10 | @ MIN | 36 | W 6-5 | 23-13 | 2 | 26,346 | Tim Wakefield | Kenny Rogers | Tim Wakefield | Juan Rincon | Brandon Lyon | 213 | 196 | 17 |
| 2003-05-11 | @ MIN | 37 | L 8-9 | 23-14 | 2 | 15,641 | Derek Lowe | Brad Radke | Brad Radke | Derek Lowe | Eddie Guardado | 221 | 205 | 16 |
| 2003-05-13 | vs TEX | 38 | W 5-4 | 24-14 | 2 | 31,956 | John Burkett | John Thomson | Alan Embree | Francisco Cordero | Brandon Lyon | 226 | 209 | 17 |
| 2003-05-14 | vs TEX | 39 | W 7-1 | 25-14 | 2 | 32,485 | Casey Fossum | Joaquin Benoit | Casey Fossum | Joaquin Benoit | | 233 | 210 | 23 |
| 2003-05-15 | vs TEX | 40 | W 12-3 | 26-14 | 2 | 33,801 | Pedro Martinez | Alan Benes | Pedro Martinez | Alan Benes | | 245 | 213 | 32 |
| 2003-05-16 | vs ANA | 41 | L 5-6 | 26-15 | 2 | 33,170 | Tim Wakefield | Ramon Ortiz | Francisco Rodriguez | Alan Embree | Troy Percival | 250 | 219 | 31 |
| 2003-05-17 | vs ANA | 42 | L 2-6 | 26-16 | 2 | 33,327 | Derek Lowe | Jarrod Washburn | Jarrod Washburn | Mike Timlin | Troy Percival | 252 | 225 | 27 |
| 2003-05-18 | vs ANA | 43 | W 5-3 | 27-16 | 1 | 33,347 | John Burkett | John Lackey | John Burkett | John Lackey | Robert Person | 257 | 228 | 29 |
| 2003-05-19 | vs NYA | 44 | L 3-7 | 27-17 | 2 | 35,099 | Casey Fossum | David Wells | David Wells | Casey Fossum | | 260 | 235 | 25 |
| 2003-05-20 | vs NYA | 45 | W 10-7 | 28-17 | 1 | 35,007 | Bruce Chen | Jeff Weaver | Alan Embree | Jose Contreras | Brandon Lyon | 270 | 242 | 28 |
| 2003-05-21 | vs NYA | 46 | L 2-4 | 28-18 | 2 | 35,003 | Tim Wakefield | Roger Clemens | Roger Clemens | Tim Wakefield | Mariano Rivera | 272 | 246 | 26 |
| 2003-05-23 | vs CLE | 47 | W 9-2 | 29-18 | 1 | 32,673 | Derek Lowe | Ricardo Rodriguez | Derek Lowe | Ricardo Rodriguez | | 281 | 248 | 33 |
| 2003-05-24 | vs CLE | 48 | W 12-3 | 30-18 | 1 | 32,643 | John Burkett | Brian Anderson | John Burkett | Brian Anderson | | 293 | 251 | 42 |
| 2003-05-25 | vs CLE | 49 | L 4-6 | 30-19 | 1 | 34,318 | Casey Fossum | Jason Davis | Jason Davis | Casey Fossum | Danys Baez | 297 | 257 | 40 |
| 2003-05-26 | @ NYA | 50 | W 8-4 | 31-19 | 1 | 55,093 | Tim Wakefield | Roger Clemens | Tim Wakefield | Roger Clemens | | 305 | 261 | 44 |
| 2003-05-27 | @ NYA | 51 | L 3-11 | 31-20 | 1 | 44,769 | Bruce Chen | Andy Pettitte | Andy Pettitte | Bruce Chen | | 308 | 272 | 36 |
| 2003-05-28 | @ NYA | 52 | L 5-6 | 31-21 | 1 | 44,617 | Derek Lowe | Mike Mussina | Mariano Rivera | Brandon Lyon | | 313 | 278 | 35 |
| 2003-05-30 | @ TOR | 53 | L 2-13 | 31-22 | 2 | 21,381 | John Burkett | Doug Davis | Doug Davis | John Burkett | | 315 | 291 | 24 |
| 2003-05-31 | @ TOR | 54 | L 7-10 | 31-23 | 2 | 28,809 | Casey Fossum | Mark Hendrickson | Tanyon Sturtze | Casey Fossum | Cliff Politte | 322 | 301 | 21 |
| 2003-06-01 | @ TOR | 55 | L 8-11 | 31-24 | 2 | 26,890 | Tim Wakefield | Roy Halladay | Roy Halladay | Matt White | | 330 | 312 | 18 |
| 2003-06-04 | @ PIT | 56 | W 11-4 | 33-24 | 1 | 0 | Byung-Hyun Kim | Kris Benson | Byung-Hyun Kim | Kris Benson | | 341 | 316 | 25 |
| 2003-06-04 | @ PIT | 57 | W 8-3 | 33-24 | 1 | 27,769 | Derek Lowe | Jeff D'Amico | Derek Lowe | Jeff D'Amico | | 349 | 319 | 30 |
| 2003-06-05 | @ PIT | 58 | L 4-5 | 33-25 | 2 | 33,372 | John Burkett | Jeff Suppan | Brian Boehringer | Ramiro Mendoza | Mike Williams | 353 | 324 | 29 |
| 2003-06-06 | @ MIL | 59 | L 3-9 | 33-26 | 2 | 20,195 | Tim Wakefield | Wayne Franklin | Jayson Durocher | Hector Almonte | | 356 | 333 | 23 |
| 2003-06-07 | @ MIL | 60 | W 11-10 | 34-26 | 2 | 34,242 | Casey Fossum | Ruben Quevedo | Brandon Lyon | Mike DeJean | Mike Timlin | 367 | 343 | 24 |
| 2003-06-08 | @ MIL | 61 | W 9-1 | 35-26 | 1 | 20,784 | Derek Lowe | Glendon Rusch | Derek Lowe | Glendon Rusch | | 376 | 344 | 32 |
| 2003-06-10 | vs SLN | 62 | L 7-9 | 35-27 | 2 | 34,937 | Byung-Hyun Kim | Woody Williams | Steve Kline | Brandon Lyon | Cal Eldred | 383 | 353 | 30 |
| 2003-06-11 | vs SLN | 63 | W 13-1 | 36-27 | 1 | 33,453 | Pedro Martinez | Brett Tomko | John Burkett | Brett Tomko | | 396 | 354 | 42 |
| 2003-06-12 | vs SLN | 64 | L 7-8 | 36-28 | 2 | 34,389 | Tim Wakefield | Garrett Stephenson | Esteban Yan | Ramiro Mendoza | | 403 | 362 | 41 |
| 2003-06-13 | vs HOU | 65 | W 4-3 | 37-28 | 2 | 33,244 | Ryan Rupe | Jonathan Johnson | Ryan Rupe | Ricky Stone | Brandon Lyon | 407 | 365 | 42 |
| 2003-06-14 | vs HOU | 66 | W 8-4 | 38-28 | 2 | 34,562 | Derek Lowe | Tim Redding | Derek Lowe | Tim Redding | | 415 | 369 | 46 |
| 2003-06-15 | vs HOU | 67 | W 3-2 | 39-28 | 2 | 34,085 | Byung-Hyun Kim | Wade Miller | Jason Shiell | Nate Bland | | 418 | 371 | 47 |
| 2003-06-16 | @ CHA | 68 | L 2-4 | 39-29 | 2 | 30,779 | Pedro Martinez | Mark Buehrle | Mark Buehrle | Ryan Rupe | Tom Gordon | 420 | 375 | 45 |
| 2003-06-17 | @ CHA | 69 | W 7-4 | 40-29 | 2 | 19,887 | John Burkett | Bartolo Colon | John Burkett | Bartolo Colon | Brandon Lyon | 427 | 379 | 48 |
| 2003-06-18 | @ CHA | 70 | L 1-3 | 40-30 | 2 | 18,708 | Tim Wakefield | Esteban Loaiza | Esteban Loaiza | Tim Wakefield | Billy Koch | 428 | 382 | 46 |
| 2003-06-19 | @ CHA | 71 | W 4-3 | 41-30 | 2 | 17,225 | Derek Lowe | Dan Wright | Brandon Lyon | Billy Koch | | 432 | 385 | 47 |
| 2003-06-21 | @ PHI | 72 | L 5-6 | 41-31 | 2 | 35,512 | Pedro Martinez | Randy Wolf | Jose Mesa | Rudy Seanez | | 437 | 391 | 46 |
| 2003-06-22 | @ PHI | 73 | L 0-5 | 41-32 | 3 | 60,960 | Byung-Hyun Kim | Brett Myers | Brett Myers | Byung-Hyun Kim | | 437 | 396 | 41 |
| 2003-06-23 | vs DET | 74 | W 3-1 | 42-32 | 3 | 33,814 | Tim Wakefield | Jeremy Bonderman | Tim Wakefield | Jeremy Bonderman | Mike Timlin | 440 | 397 | 43 |
| 2003-06-24 | vs DET | 75 | W 10-1 | 43-32 | 2 | 33,848 | Derek Lowe | Nate Cornejo | Derek Lowe | Nate Cornejo | | 450 | 398 | 52 |
| 2003-06-25 | vs DET | 76 | W 11-2 | 44-32 | 2 | 33,587 | John Burkett | Mike Maroth | John Burkett | Mike Maroth | | 461 | 400 | 61 |
| 2003-06-26 | vs DET | 77 | W 6-4 | 45-32 | 2 | 34,415 | Pedro Martinez | Matt Roney | Pedro Martinez | Matt Roney | Brandon Lyon | 467 | 404 | 63 |
| 2003-06-27 | vs FLO | 78 | W 25-8 | 46-32 | 2 | 34,764 | Byung-Hyun Kim | Carl Pavano | Byung-Hyun Kim | Carl Pavano | | 492 | 412 | 80 |
| 2003-06-28 | vs FLO | 79 | L 9-10 | 46-33 | 2 | 34,804 | Tim Wakefield | Tommy Phelps | Nate Bump | Brandon Lyon | Braden Looper | 501 | 422 | 79 |
| 2003-06-29 | vs FLO | 80 | W 11-7 | 47-33 | 2 | 34,476 | Derek Lowe | Brad Penny | Derek Lowe | Brad Penny | | 512 | 429 | 83 |
| 2003-07-01 | @ TBA | 81 | L 3-4 | 47-34 | 2 | 12,122 | John Burkett | Jason Standridge | Lance Carter | Brandon Lyon | | 515 | 433 | 82 |
| 2003-07-02 | @ TBA | 82 | W 5-4 | 48-34 | 2 | 14,345 | Pedro Martinez | Rob Bell | Pedro Martinez | Jesus Colome | Byung-Hyun Kim | 520 | 437 | 83 |
| 2003-07-03 | @ TBA | 83 | L 5-6 | 48-35 | 2 | 12,838 | Tim Wakefield | Geremi Gonzalez | Travis Harper | Mike Timlin | | 525 | 443 | 82 |
| 2003-07-04 | @ NYA | 84 | W 10-3 | 49-35 | 2 | 55,144 | Derek Lowe | David Wells | Derek Lowe | David Wells | | 535 | 446 | 89 |
| 2003-07-05 | @ NYA | 85 | W 10-2 | 50-35 | 2 | 54,948 | Ramiro Mendoza | Roger Clemens | Ramiro Mendoza | Roger Clemens | | 545 | 448 | 97 |
| 2003-07-06 | @ NYA | 86 | L 1-7 | 50-36 | 2 | 54,918 | John Burkett | Andy Pettitte | Andy Pettitte | John Burkett | | 546 | 455 | 91 |
| 2003-07-07 | @ NYA | 87 | L 1-2 | 50-37 | 2 | 55,016 | Pedro Martinez | Mike Mussina | Mariano Rivera | Byung-Hyun Kim | | 547 | 457 | 90 |
| 2003-07-08 | @ TOR | 88 | W 2-1 | 51-37 | 2 | 20,022 | Tim Wakefield | Roy Halladay | Todd Jones | Jeff Tam | Byung-Hyun Kim | 549 | 458 | 91 |
| 2003-07-09 | @ TOR | 89 | W 8-7 | 52-37 | 2 | 23,551 | Derek Lowe | Kelvim Escobar | Brandon Lyon | Jeff Tam | Byung-Hyun Kim | 557 | 465 | 92 |
| 2003-07-10 | @ TOR | 90 | W 7-1 | 53-37 | 2 | 20,113 | Ramiro Mendoza | Cory Lidle | Ramiro Mendoza | Cory Lidle | | 564 | 466 | 98 |
| 2003-07-11 | @ DET | 91 | W 5-3 | 54-37 | 2 | 26,538 | John Burkett | Mike Maroth | John Burkett | Mike Maroth | Byung-Hyun Kim | 569 | 469 | 100 |
| 2003-07-12 | @ DET | 92 | W 4-2 | 55-37 | 2 | 23,206 | Pedro Martinez | Matt Roney | Todd Jones | Fernando Rodney | Byung-Hyun Kim | 573 | 471 | 102 |
| 2003-07-13 | @ DET | 93 | L 0-3 | 55-38 | 2 | 23,829 | Tim Wakefield | Wil Ledezma | Wil Ledezma | Tim Wakefield | Chris Mears | 573 | 474 | 99 |
| 2003-07-17 | vs TOR | 94 | L 2-5 | 55-39 | 2 | 34,521 | Derek Lowe | Roy Halladay | Roy Halladay | Derek Lowe | | 575 | 479 | 96 |
| 2003-07-18 | vs TOR | 95 | L 1-4 | 55-40 | 2 | 34,136 | Tim Wakefield | Kelvim Escobar | Kelvim Escobar | Tim Wakefield | Trever Miller | 576 | 483 | 93 |
| 2003-07-19 | vs TOR | 96 | W 5-4 | 56-40 | 2 | 34,812 | Ramiro Mendoza | Cory Lidle | Byung-Hyun Kim | Aquilino Lopez | | 581 | 487 | 94 |
| 2003-07-20 | vs TOR | 97 | W 9-4 | 57-40 | 2 | 34,321 | Pedro Martinez | John Wasdin | Pedro Martinez | John Wasdin | | 590 | 491 | 99 |
| 2003-07-21 | vs DET | 98 | W 14-5 | 58-40 | 2 | 33,823 | John Burkett | Jeremy Bonderman | John Burkett | Jeremy Bonderman | Casey Fossum | 604 | 496 | 108 |
| 2003-07-22 | vs DET | 99 | W 7-4 | 59-40 | 2 | 33,570 | Derek Lowe | Mike Maroth | Derek Lowe | Mike Maroth | | 611 | 500 | 111 |
| 2003-07-23 | vs TBA | 100 | W 10-4 | 60-40 | 2 | 33,446 | Tim Wakefield | Geremi Gonzalez | Tim Wakefield | Travis Harper | | 621 | 504 | 117 |
| 2003-07-24 | vs TBA | 101 | L 9-15 | 60-41 | 2 | 33,521 | Ramiro Mendoza | Victor Zambrano | Victor Zambrano | Ramiro Mendoza | | 630 | 519 | 111 |
| 2003-07-25 | vs NYA | 102 | L 3-4 | 60-42 | 2 | 34,873 | Pedro Martinez | David Wells | Mariano Rivera | Byung-Hyun Kim | | 633 | 523 | 110 |
| 2003-07-26 | vs NYA | 103 | W 5-4 | 61-42 | 2 | 34,356 | John Burkett | Mike Mussina | Byung-Hyun Kim | Armando Benitez | | 638 | 527 | 111 |
| 2003-07-27 | vs NYA | 104 | W 6-4 | 62-42 | 2 | 34,787 | Derek Lowe | Jeff Weaver | Casey Fossum | Chris Hammond | Byung-Hyun Kim | 644 | 531 | 113 |
| 2003-07-29 | @ TEX | 105 | W 14-7 | 63-42 | 2 | 24,632 | Tim Wakefield | R.A. Dickey | Tim Wakefield | Rosman Garcia | | 658 | 538 | 120 |
| 2003-07-30 | @ TEX | 106 | L 2-9 | 63-43 | 2 | 25,354 | Ramiro Mendoza | Robert Ellis | Robert Ellis | Ramiro Mendoza | | 660 | 547 | 113 |
| 2003-07-31 | @ TEX | 107 | L 3-7 | 63-44 | 2 | 27,108 | Pedro Martinez | Colby Lewis | Erasmo Ramirez | Todd Jones | | 663 | 554 | 109 |
| 2003-08-01 | @ BAL | 108 | L 1-2 | 63-45 | 2 | 41,188 | John Burkett | Pat Hentgen | Pat Hentgen | John Burkett | Jorge Julio | 664 | 556 | 108 |
| 2003-08-02 | @ BAL | 109 | L 2-11 | 63-46 | 2 | 49,334 | Derek Lowe | Rodrigo Lopez | Rodrigo Lopez | Derek Lowe | | 666 | 567 | 99 |
| 2003-08-03 | @ BAL | 110 | W 7-5 | 64-46 | 2 | 42,085 | Tim Wakefield | Rick Helling | Tim Wakefield | Rick Helling | Byung-Hyun Kim | 673 | 572 | 101 |
| 2003-08-05 | vs ANA | 111 | W 10-9 | 65-46 | 2 | 34,678 | Jeff Suppan | John Lackey | Mike Timlin | Brendan Donnelly | Byung-Hyun Kim | 683 | 581 | 102 |
| 2003-08-06 | vs ANA | 112 | W 4-2 | 66-46 | 2 | 35,040 | Pedro Martinez | Aaron Sele | Pedro Martinez | Aaron Sele | | 687 | 583 | 104 |
| 2003-08-07 | vs ANA | 113 | W 9-3 | 67-46 | 2 | 34,570 | John Burkett | Ramon Ortiz | John Burkett | Ramon Ortiz | | 696 | 586 | 110 |
| 2003-08-08 | vs BAL | 114 | L 4-10 | 67-48 | 2 | 35,099 | Derek Lowe | Rick Helling | Rick Helling | Derek Lowe | | 700 | 596 | 104 |
| 2003-08-08 | vs BAL | 115 | L 2-4 | 67-48 | 2 | 34,595 | Casey Fossum | Eric DuBose | Eric DuBose | Casey Fossum | Jorge Julio | 702 | 600 | 102 |
| 2003-08-09 | vs BAL | 116 | W 6-4 | 68-48 | 2 | 34,883 | Tim Wakefield | Damian Moss | Alan Embree | Travis Driskill | Byung-Hyun Kim | 708 | 604 | 104 |
| 2003-08-10 | vs BAL | 117 | L 3-5 | 68-49 | 2 | 34,239 | Jeff Suppan | Jason Johnson | Jason Johnson | Jeff Suppan | Jorge Julio | 711 | 609 | 102 |
| 2003-08-11 | @ OAK | 118 | L 0-4 | 68-50 | 2 | 33,504 | Pedro Martinez | Tim Hudson | Tim Hudson | Pedro Martinez | | 711 | 613 | 98 |
| 2003-08-12 | @ OAK | 119 | L 3-5 | 68-51 | 2 | 26,823 | John Burkett | Barry Zito | Barry Zito | John Burkett | Keith Foulke | 714 | 618 | 96 |
| 2003-08-13 | @ OAK | 120 | W 7-3 | 69-51 | 2 | 44,868 | Derek Lowe | Mark Mulder | Derek Lowe | Mark Mulder | | 721 | 621 | 100 |
| 2003-08-14 | @ OAK | 121 | W 4-2 | 70-51 | 2 | 37,293 | Tim Wakefield | Ted Lilly | Byung-Hyun Kim | Jim Mecir | | 725 | 623 | 102 |
| 2003-08-15 | @ SEA | 122 | L 5-10 | 70-52 | 2 | 46,171 | Jeff Suppan | Jamie Moyer | Julio Mateo | Mike Timlin | Shigetoshi Hasegawa | 730 | 633 | 97 |
| 2003-08-16 | @ SEA | 123 | W 5-1 | 71-52 | 2 | 46,100 | Pedro Martinez | Joel Pineiro | Pedro Martinez | Joel Pineiro | | 735 | 634 | 101 |
| 2003-08-17 | @ SEA | 124 | L 1-3 | 71-53 | 2 | 46,105 | John Burkett | Freddy Garcia | Freddy Garcia | John Burkett | Shigetoshi Hasegawa | 736 | 637 | 99 |
| 2003-08-19 | vs OAK | 125 | L 2-3 | 71-54 | 2 | 34,879 | Derek Lowe | Mark Mulder | Ricardo Rincon | Scott Williamson | Keith Foulke | 738 | 640 | 98 |
| 2003-08-20 | vs OAK | 126 | L 6-8 | 71-55 | 2 | 34,798 | Tim Wakefield | Ted Lilly | Chad Bradford | Byung-Hyun Kim | Keith Foulke | 744 | 648 | 96 |
| 2003-08-21 | vs OAK | 127 | W 14-5 | 72-55 | 2 | 34,844 | Casey Fossum | Rich Harden | Casey Fossum | Rich Harden | | 758 | 653 | 105 |
| 2003-08-22 | vs SEA | 128 | W 6-4 | 73-55 | 2 | 34,379 | Jeff Suppan | Joel Pineiro | Jeff Suppan | Joel Pineiro | Byung-Hyun Kim | 764 | 657 | 107 |
| 2003-08-23 | vs SEA | 129 | W 7-6 | 74-55 | 2 | 34,488 | John Burkett | Freddy Garcia | Mike Timlin | Kazuhiro Sasaki | | 771 | 663 | 108 |
| 2003-08-24 | vs SEA | 130 | W 6-1 | 75-55 | 2 | 34,344 | Derek Lowe | Ryan Franklin | Derek Lowe | Ryan Franklin | | 777 | 664 | 113 |
| 2003-08-25 | vs SEA | 131 | W 8-1 | 76-55 | 2 | 33,007 | Pedro Martinez | Gil Meche | Pedro Martinez | Gil Meche | Bronson Arroyo | 785 | 665 | 120 |
| 2003-08-26 | vs TOR | 132 | L 9-12 | 76-56 | 2 | 33,731 | Tim Wakefield | Mark Hendrickson | Josh Towers | Scott Sauerbeck | Aquilino Lopez | 794 | 677 | 117 |
| 2003-08-27 | vs TOR | 133 | W 6-3 | 77-56 | 2 | 34,206 | John Burkett | Roy Halladay | Mike Timlin | Roy Halladay | Byung-Hyun Kim | 800 | 680 | 120 |
| 2003-08-29 | vs NYA | 134 | W 10-5 | 78-56 | 2 | 34,854 | Derek Lowe | Jose Contreras | Derek Lowe | Jose Contreras | | 810 | 685 | 125 |
| 2003-08-30 | vs NYA | 135 | L 7-10 | 78-57 | 2 | 34,350 | Pedro Martinez | Andy Pettitte | Andy Pettitte | Pedro Martinez | Mariano Rivera | 817 | 695 | 122 |
| 2003-08-31 | vs NYA | 136 | L 4-8 | 78-58 | 2 | 34,482 | Tim Wakefield | Roger Clemens | Roger Clemens | Tim Wakefield | Mariano Rivera | 821 | 703 | 118 |
| 2003-09-01 | @ PHI | 137 | W 13-9 | 79-58 | 2 | 61,068 | Jeff Suppan | Brett Myers | Byung-Hyun Kim | Jose Mesa | | 834 | 712 | 122 |
| 2003-09-02 | @ CHA | 138 | W 2-1 | 80-58 | 2 | 23,943 | John Burkett | Bartolo Colon | John Burkett | Bartolo Colon | Byung-Hyun Kim | 836 | 713 | 123 |
| 2003-09-03 | @ CHA | 139 | W 5-4 | 81-58 | 2 | 20,082 | Derek Lowe | Mark Buehrle | Byung-Hyun Kim | Tom Gordon | | 841 | 717 | 124 |
| 2003-09-05 | @ NYA | 140 | W 9-3 | 82-58 | 2 | 55,261 | Pedro Martinez | Andy Pettitte | Pedro Martinez | Andy Pettitte | | 850 | 720 | 130 |
| 2003-09-06 | @ NYA | 141 | W 11-0 | 83-58 | 2 | 55,237 | Tim Wakefield | Roger Clemens | Tim Wakefield | Roger Clemens | | 861 | 720 | 141 |
| 2003-09-07 | @ NYA | 142 | L 1-3 | 83-59 | 2 | 55,212 | Jeff Suppan | David Wells | David Wells | Jeff Suppan | Mariano Rivera | 862 | 723 | 139 |
| 2003-09-08 | @ BAL | 143 | L 10-13 | 83-60 | 2 | 23,276 | John Burkett | Rodrigo Lopez | Kerry Ligtenberg | Byung-Hyun Kim | | 872 | 736 | 136 |
| 2003-09-09 | @ BAL | 144 | W 9-2 | 84-60 | 2 | 25,265 | Derek Lowe | Damian Moss | Derek Lowe | Damian Moss | | 881 | 738 | 143 |
| 2003-09-10 | @ BAL | 145 | W 5-0 | 85-60 | 2 | 25,143 | Pedro Martinez | Jason Johnson | Pedro Martinez | Jason Johnson | | 886 | 738 | 148 |
| 2003-09-12 | vs CHA | 146 | W 7-4 | 86-60 | 2 | 34,890 | Jeff Suppan | Dan Wright | Jeff Suppan | Dan Wright | Byung-Hyun Kim | 893 | 742 | 151 |
| 2003-09-13 | vs CHA | 147 | L 1-3 | 86-61 | 2 | 34,414 | Tim Wakefield | Bartolo Colon | Bartolo Colon | Tim Wakefield | | 894 | 745 | 149 |
| 2003-09-14 | vs CHA | 148 | L 2-7 | 86-62 | 2 | 34,174 | John Burkett | Mark Buehrle | Mark Buehrle | John Burkett | Damaso Marte | 896 | 752 | 144 |
| 2003-09-15 | vs TBA | 149 | W 8-2 | 87-62 | 2 | 33,389 | Derek Lowe | Jorge Sosa | Derek Lowe | Jorge Sosa | | 904 | 754 | 150 |
| 2003-09-16 | vs TBA | 150 | W 3-2 | 88-62 | 2 | 33,618 | Pedro Martinez | Geremi Gonzalez | Pedro Martinez | Travis Harper | | 907 | 756 | 151 |
| 2003-09-17 | vs TBA | 151 | L 0-7 | 88-63 | 2 | 33,806 | Jeff Suppan | Victor Zambrano | Victor Zambrano | Jeff Suppan | | 907 | 763 | 144 |
| 2003-09-18 | vs TBA | 152 | W 4-3 | 89-63 | 2 | 34,042 | Tim Wakefield | Rob Bell | Tim Wakefield | Rob Bell | Byung-Hyun Kim | 911 | 766 | 145 |
| 2003-09-19 | @ CLE | 153 | W 2-0 | 90-63 | 2 | 20,374 | John Burkett | Jason Stanford | John Burkett | Jason Stanford | Alan Embree | 913 | 766 | 147 |
| 2003-09-20 | @ CLE | 154 | L 4-13 | 90-64 | 2 | 23,242 | Derek Lowe | Terry Mulholland | David Lee | Derek Lowe | | 917 | 779 | 138 |
| 2003-09-21 | @ CLE | 155 | W 2-0 | 91-64 | 2 | 27,655 | Pedro Martinez | Cliff Lee | Pedro Martinez | Cliff Lee | Byung-Hyun Kim | 919 | 779 | 140 |
| 2003-09-22 | vs BAL | 156 | W 7-5 | 92-64 | 2 | 33,821 | Jeff Suppan | Jason Johnson | Jeff Suppan | Jason Johnson | Byung-Hyun Kim | 926 | 784 | 142 |
| 2003-09-23 | vs BAL | 157 | W 6-5 | 93-64 | 2 | 33,723 | Tim Wakefield | Eric DuBose | Byung-Hyun Kim | Kurt Ainsworth | | 932 | 789 | 143 |
| 2003-09-24 | vs BAL | 158 | L 3-7 | 93-65 | 2 | 34,607 | John Burkett | Pat Hentgen | Pat Hentgen | John Burkett | | 935 | 796 | 139 |
| 2003-09-25 | vs BAL | 159 | W 14-3 | 94-65 | 2 | 34,526 | Derek Lowe | Omar Daal | Derek Lowe | Omar Daal | | 949 | 799 | 150 |
| 2003-09-26 | @ TBA | 160 | W 7-2 | 95-65 | 2 | 21,240 | Pedro Martinez | Geremi Gonzalez | John Burkett | Geremi Gonzalez | | 956 | 801 | 155 |
| 2003-09-27 | @ TBA | 161 | L 4-5 | 95-66 | 2 | 25,635 | Jeff Suppan | Rob Bell | Chad Gaudin | Jeff Suppan | Lance Carter | 960 | 806 | 154 |
| 2003-09-28 | @ TBA | 162 | L 1-3 | 95-67 | 2 | 24,138 | Tim Wakefield | Victor Zambrano | Victor Zambrano | Brandon Lyon | Lance Carter | 961 | 809 | 152 |