| 2005-04-04 | @ DET | 1 | L 2-11 | 0-1 | 4 | 44,105 | Jose Lima | Jeremy Bonderman | Jeremy Bonderman | Jose Lima | | 2 | 11 | -9 |
| 2005-04-06 | @ DET | 2 | W 7-2 | 1-1 | 4 | 14,168 | Runelvys Hernandez | Mike Maroth | Runelvys Hernandez | Mike Maroth | | 9 | 13 | -4 |
| 2005-04-07 | @ DET | 3 | L 3-7 | 1-2 | 5 | 10,463 | Zack Greinke | Jason Johnson | Jason Johnson | Mike Wood | | 12 | 20 | -8 |
| 2005-04-08 | @ ANA | 4 | W 6-2 | 2-2 | 4 | 39,167 | Denny Bautista | Paul Byrd | Denny Bautista | Paul Byrd | | 18 | 22 | -4 |
| 2005-04-09 | @ ANA | 5 | L 3-8 | 2-3 | 4 | 42,007 | Jose Lima | Kevin Gregg | Kevin Gregg | Jose Lima | | 21 | 30 | -9 |
| 2005-04-10 | @ ANA | 6 | W 8-3 | 3-3 | 4 | 40,689 | Brian Anderson | Bartolo Colon | Brian Anderson | Bartolo Colon | | 29 | 33 | -4 |
| 2005-04-11 | vs SEA | 7 | L 2-8 | 3-4 | 5 | 41,788 | Runelvys Hernandez | Ryan Franklin | Ryan Franklin | Runelvys Hernandez | | 31 | 41 | -10 |
| 2005-04-13 | vs SEA | 8 | L 1-2 | 3-5 | 5 | 10,577 | Zack Greinke | Aaron Sele | Aaron Sele | Jaime Cerda | Eddie Guardado | 32 | 43 | -11 |
| 2005-04-14 | vs SEA | 9 | L 2-10 | 3-6 | 5 | 10,212 | Denny Bautista | Jamie Moyer | Jamie Moyer | Denny Bautista | | 34 | 53 | -19 |
| 2005-04-15 | vs DET | 10 | W 6-5 | 4-6 | 4 | 29,720 | Jose Lima | Wil Ledezma | Jaime Cerda | Ugueth Urbina | Mike MacDougal | 40 | 58 | -18 |
| 2005-04-16 | vs DET | 11 | L 1-7 | 4-7 | 5 | 22,881 | Brian Anderson | Jeremy Bonderman | Jeremy Bonderman | Brian Anderson | | 41 | 65 | -24 |
| 2005-04-17 | vs DET | 12 | L 1-6 | 4-8 | 5 | 14,904 | Runelvys Hernandez | Mike Maroth | Mike Maroth | Runelvys Hernandez | | 42 | 71 | -29 |
| 2005-04-18 | vs CLE | 13 | L 1-5 | 4-9 | 5 | 11,115 | Zack Greinke | Cliff Lee | Cliff Lee | Zack Greinke | | 43 | 76 | -33 |
| 2005-04-19 | vs CLE | 14 | W 6-5 | 5-9 | 5 | 11,884 | Denny Bautista | Scott Elarton | Mike MacDougal | Arthur Rhodes | | 49 | 81 | -32 |
| 2005-04-20 | @ MIN | 15 | L 4-5 | 5-10 | 5 | 24,153 | Jose Lima | Johan Santana | Juan Rincon | Jaime Cerda | Joe Nathan | 53 | 86 | -33 |
| 2005-04-21 | @ MIN | 16 | L 9-10 | 5-11 | 5 | 15,914 | Brian Anderson | Dave Gassner | Joe Nathan | Shawn Camp | | 62 | 96 | -34 |
| 2005-04-22 | vs CHA | 17 | L 2-8 | 5-12 | 5 | 15,832 | Runelvys Hernandez | Freddy Garcia | Freddy Garcia | Runelvys Hernandez | | 64 | 104 | -40 |
| 2005-04-23 | vs CHA | 18 | L 2-3 | 5-13 | 5 | 19,641 | Zack Greinke | Jose Contreras | Damaso Marte | Mike MacDougal | | 66 | 107 | -41 |
| 2005-04-24 | vs CHA | 19 | L 3-4 | 5-14 | 5 | 15,331 | Denny Bautista | Orlando Hernandez | Neal Cotts | Shawn Camp | Shingo Takatsu | 69 | 111 | -42 |
| 2005-04-26 | vs MIN | 20 | L 1-2 | 5-15 | 5 | 10,133 | Jose Lima | Johan Santana | Johan Santana | Ambiorix Burgos | Joe Nathan | 70 | 113 | -43 |
| 2005-04-27 | vs MIN | 21 | L 4-9 | 5-16 | 5 | 10,393 | Brian Anderson | Joe Mays | Joe Mays | Brian Anderson | | 74 | 122 | -48 |
| 2005-04-28 | vs MIN | 22 | L 5-6 | 5-17 | 5 | 10,852 | Runelvys Hernandez | Kyle Lohse | Jesse Crain | Mike Wood | | 79 | 128 | -49 |
| 2005-04-29 | @ CLE | 23 | L 0-6 | 5-18 | 5 | 16,666 | Zack Greinke | CC Sabathia | CC Sabathia | Zack Greinke | | 79 | 134 | -55 |
| 2005-04-30 | @ CLE | 24 | W 8-1 | 6-18 | 5 | 15,771 | Denny Bautista | Cliff Lee | Denny Bautista | Cliff Lee | | 87 | 135 | -48 |
| 2005-05-01 | @ CLE | 25 | W 6-5 | 7-18 | 5 | 17,672 | Jose Lima | Scott Elarton | Mike Wood | Rafael Betancourt | Ambiorix Burgos | 93 | 140 | -47 |
| 2005-05-03 | @ CHA | 26 | L 4-5 | 7-19 | 5 | 12,362 | Brian Anderson | Mark Buehrle | Mark Buehrle | Andy Sisco | Shingo Takatsu | 97 | 145 | -48 |
| 2005-05-04 | @ CHA | 27 | L 2-4 | 7-20 | 5 | 12,712 | Runelvys Hernandez | Freddy Garcia | Freddy Garcia | Runelvys Hernandez | Dustin Hermanson | 99 | 149 | -50 |
| 2005-05-05 | @ CHA | 28 | L 1-2 | 7-21 | 5 | 15,389 | Zack Greinke | Jose Contreras | Jose Contreras | Zack Greinke | Shingo Takatsu | 100 | 151 | -51 |
| 2005-05-06 | @ BAL | 29 | L 1-3 | 7-22 | 5 | 30,568 | Denny Bautista | Sidney Ponson | Sidney Ponson | Denny Bautista | B.J. Ryan | 101 | 154 | -53 |
| 2005-05-07 | @ BAL | 30 | L 3-5 | 7-23 | 5 | 30,084 | Jose Lima | Bruce Chen | Bruce Chen | Jose Lima | B.J. Ryan | 104 | 159 | -55 |
| 2005-05-08 | @ BAL | 31 | W 10-8 | 8-23 | 5 | 35,252 | Brian Anderson | Rodrigo Lopez | Ambiorix Burgos | Todd Williams | | 114 | 167 | -53 |
| 2005-05-09 | @ TOR | 32 | L 1-6 | 8-24 | 5 | 13,839 | Runelvys Hernandez | Josh Towers | Josh Towers | Runelvys Hernandez | | 115 | 173 | -58 |
| 2005-05-10 | @ TOR | 33 | L 1-3 | 8-25 | 5 | 20,123 | Zack Greinke | Roy Halladay | Roy Halladay | Zack Greinke | | 116 | 176 | -60 |
| 2005-05-11 | @ TOR | 34 | L 9-12 | 8-26 | 5 | 24,402 | Denny Bautista | David Bush | Miguel Batista | Ambiorix Burgos | | 125 | 188 | -63 |
| 2005-05-12 | vs TBA | 35 | W 7-5 | 9-26 | 5 | 10,807 | Jose Lima | Scott Kazmir | Mike Wood | Lance Carter | | 132 | 193 | -61 |
| 2005-05-13 | vs TBA | 36 | L 2-3 | 9-27 | 5 | 19,547 | D.J. Carrasco | Doug Waechter | Danys Baez | Ambiorix Burgos | | 134 | 196 | -62 |
| 2005-05-14 | vs TBA | 37 | W 6-5 | 10-27 | 5 | 17,151 | Runelvys Hernandez | Hideo Nomo | Runelvys Hernandez | Jesus Colome | Mike Wood | 140 | 201 | -61 |
| 2005-05-15 | vs TBA | 38 | W 4-3 | 11-27 | 5 | 12,000 | Zack Greinke | Mark Hendrickson | Mike MacDougal | Mark Hendrickson | Mike Wood | 144 | 204 | -60 |
| 2005-05-17 | vs BAL | 39 | L 8-12 | 11-28 | 5 | 13,274 | Jose Lima | Sidney Ponson | John Parrish | Jaime Cerda | B.J. Ryan | 152 | 216 | -64 |
| 2005-05-18 | vs BAL | 40 | L 4-7 | 11-29 | 5 | 10,375 | D.J. Carrasco | Bruce Chen | Bruce Chen | D.J. Carrasco | B.J. Ryan | 156 | 223 | -67 |
| 2005-05-19 | vs BAL | 41 | W 7-4 | 12-29 | 5 | 25,419 | Runelvys Hernandez | Rodrigo Lopez | Leo Nunez | Rodrigo Lopez | Mike MacDougal | 163 | 227 | -64 |
| 2005-05-20 | vs SLN | 42 | L 6-7 | 12-30 | 5 | 31,513 | Zack Greinke | Mark Mulder | Mark Mulder | Zack Greinke | Jason Isringhausen | 169 | 234 | -65 |
| 2005-05-21 | vs SLN | 43 | L 5-6 | 12-31 | 5 | 39,781 | Jose Lima | Matt Morris | Matt Morris | Jaime Cerda | Jason Isringhausen | 174 | 240 | -66 |
| 2005-05-22 | vs SLN | 44 | W 9-2 | 13-31 | 5 | 29,269 | Ryan Jensen | Jeff Suppan | Ryan Jensen | Jeff Suppan | | 183 | 242 | -59 |
| 2005-05-24 | @ TEX | 45 | L 3-4 | 13-32 | 5 | 27,449 | Runelvys Hernandez | Ryan Drese | Ryan Drese | Runelvys Hernandez | Francisco Cordero | 186 | 246 | -60 |
| 2005-05-25 | @ TEX | 46 | L 3-7 | 13-33 | 5 | 23,755 | Zack Greinke | Pedro Astacio | Pedro Astacio | Zack Greinke | | 189 | 253 | -64 |
| 2005-05-26 | @ TEX | 47 | L 1-8 | 13-34 | 5 | 25,022 | Jose Lima | Kenny Rogers | Kenny Rogers | Jose Lima | | 190 | 261 | -71 |
| 2005-05-27 | @ ANA | 48 | L 8-9 | 13-35 | 5 | 40,834 | D.J. Carrasco | Paul Byrd | Scot Shields | Mike MacDougal | | 198 | 270 | -72 |
| 2005-05-28 | @ ANA | 49 | L 1-14 | 13-36 | 5 | 43,929 | Ryan Jensen | Kelvim Escobar | Kelvim Escobar | Ryan Jensen | Chris Bootcheck | 199 | 284 | -85 |
| 2005-05-29 | @ ANA | 50 | L 6-7 | 13-37 | 5 | 42,345 | Runelvys Hernandez | Bartolo Colon | Bartolo Colon | Runelvys Hernandez | Scot Shields | 205 | 291 | -86 |
| 2005-05-31 | vs NYA | 51 | W 5-3 | 14-37 | 5 | 18,680 | Zack Greinke | Kevin Brown | Zack Greinke | Kevin Brown | Mike MacDougal | 210 | 294 | -84 |
| 2005-06-01 | vs NYA | 52 | W 3-1 | 15-37 | 5 | 28,033 | D.J. Carrasco | Randy Johnson | D.J. Carrasco | Randy Johnson | Mike MacDougal | 213 | 295 | -82 |
| 2005-06-02 | vs NYA | 53 | W 5-2 | 16-37 | 5 | 25,590 | Ryan Jensen | Carl Pavano | Ryan Jensen | Carl Pavano | Ambiorix Burgos | 218 | 297 | -79 |
| 2005-06-03 | vs TEX | 54 | W 2-1 | 17-37 | 5 | 11,635 | Runelvys Hernandez | Pedro Astacio | Andy Sisco | Pedro Astacio | Mike MacDougal | 220 | 298 | -78 |
| 2005-06-04 | vs TEX | 55 | L 9-14 | 17-38 | 5 | 18,808 | Jose Lima | Chan Ho Park | Chan Ho Park | Jose Lima | | 229 | 312 | -83 |
| 2005-06-05 | vs TEX | 56 | L 1-8 | 17-39 | 5 | 21,424 | Zack Greinke | Kenny Rogers | Kenny Rogers | Zack Greinke | | 230 | 320 | -90 |
| 2005-06-07 | @ SFN | 57 | W 8-1 | 18-39 | 5 | 37,037 | D.J. Carrasco | Kirk Rueter | D.J. Carrasco | Kirk Rueter | | 238 | 321 | -83 |
| 2005-06-08 | @ SFN | 58 | W 4-1 | 19-39 | 5 | 36,578 | Runelvys Hernandez | Jeff Fassero | Runelvys Hernandez | Jeff Fassero | Mike MacDougal | 242 | 322 | -80 |
| 2005-06-09 | @ SFN | 59 | L 7-9 | 19-40 | 5 | 38,956 | Jose Lima | Noah Lowry | Scott Munter | Leo Nunez | Tyler Walker | 249 | 331 | -82 |
| 2005-06-10 | @ ARI | 60 | L 11-12 | 19-41 | 5 | 22,731 | Zack Greinke | Russ Ortiz | Brian Bruney | Mike MacDougal | | 260 | 343 | -83 |
| 2005-06-11 | @ ARI | 61 | W 8-5 | 20-41 | 5 | 27,996 | J.P. Howell | Brad Halsey | J.P. Howell | Brad Halsey | | 268 | 348 | -80 |
| 2005-06-12 | @ ARI | 62 | W 9-4 | 21-41 | 5 | 25,965 | D.J. Carrasco | Brandon Webb | Ryan Jensen | Javier Lopez | | 277 | 352 | -75 |
| 2005-06-14 | vs LAN | 63 | W 3-2 | 22-41 | 5 | 15,579 | Runelvys Hernandez | Jeff Weaver | Runelvys Hernandez | Jeff Weaver | Mike MacDougal | 280 | 354 | -74 |
| 2005-06-15 | vs LAN | 64 | W 3-1 | 23-41 | 5 | 21,024 | Jose Lima | Brad Penny | Jose Lima | Brad Penny | Mike MacDougal | 283 | 355 | -72 |
| 2005-06-16 | vs LAN | 65 | W 9-6 | 24-41 | 5 | 16,182 | Zack Greinke | Derek Lowe | Mike Wood | Derek Lowe | | 292 | 361 | -69 |
| 2005-06-17 | vs HOU | 66 | L 0-7 | 24-42 | 5 | 27,385 | J.P. Howell | Roger Clemens | Roger Clemens | J.P. Howell | | 292 | 368 | -76 |
| 2005-06-18 | vs HOU | 67 | L 2-6 | 24-43 | 5 | 26,523 | D.J. Carrasco | Roy Oswalt | Roy Oswalt | D.J. Carrasco | | 294 | 374 | -80 |
| 2005-06-19 | vs HOU | 68 | W 7-1 | 25-43 | 5 | 20,214 | Runelvys Hernandez | Brandon Backe | Runelvys Hernandez | Brandon Backe | | 301 | 375 | -74 |
| 2005-06-20 | @ CHA | 69 | L 8-11 | 25-44 | 5 | 34,345 | Jose Lima | Brandon McCarthy | Neal Cotts | Ryan Jensen | Dustin Hermanson | 309 | 386 | -77 |
| 2005-06-21 | @ CHA | 70 | L 1-5 | 25-45 | 5 | 28,206 | Zack Greinke | Jon Garland | Jon Garland | Zack Greinke | | 310 | 391 | -81 |
| 2005-06-22 | @ CHA | 71 | L 1-5 | 25-46 | 5 | 24,544 | J.P. Howell | Mark Buehrle | Mark Buehrle | J.P. Howell | | 311 | 396 | -85 |
| 2005-06-24 | @ COL | 72 | L 4-12 | 25-47 | 5 | 24,584 | D.J. Carrasco | Byung-Hyun Kim | Byung-Hyun Kim | D.J. Carrasco | | 315 | 408 | -93 |
| 2005-06-25 | @ COL | 73 | L 2-4 | 25-48 | 5 | 27,673 | Runelvys Hernandez | Jeff Francis | Jeff Francis | Runelvys Hernandez | Brian Fuentes | 317 | 412 | -95 |
| 2005-06-26 | @ COL | 74 | L 4-9 | 25-49 | 5 | 21,080 | Jose Lima | Joe Kennedy | Joe Kennedy | Jose Lima | | 321 | 421 | -100 |
| 2005-06-27 | @ MIN | 75 | L 1-3 | 25-50 | 5 | 16,530 | Zack Greinke | Joe Mays | Joe Mays | Zack Greinke | Joe Nathan | 322 | 424 | -102 |
| 2005-06-28 | @ MIN | 76 | L 8-11 | 25-51 | 5 | 19,422 | J.P. Howell | Carlos Silva | Jesse Crain | Andy Sisco | Joe Nathan | 330 | 435 | -105 |
| 2005-06-29 | @ MIN | 77 | W 3-1 | 26-51 | 5 | 24,546 | D.J. Carrasco | Brad Radke | D.J. Carrasco | Brad Radke | Mike MacDougal | 333 | 436 | -103 |
| 2005-07-01 | vs ANA | 78 | L 0-5 | 26-52 | 5 | 17,893 | Runelvys Hernandez | Paul Byrd | Paul Byrd | Runelvys Hernandez | | 333 | 441 | -108 |
| 2005-07-02 | vs ANA | 79 | L 3-5 | 26-53 | 5 | 16,051 | Jose Lima | Bartolo Colon | Bartolo Colon | Jose Lima | Francisco Rodriguez | 336 | 446 | -110 |
| 2005-07-03 | vs ANA | 80 | L 0-5 | 26-54 | 5 | 14,872 | Zack Greinke | Jarrod Washburn | Jarrod Washburn | Zack Greinke | | 336 | 451 | -115 |
| 2005-07-04 | vs SEA | 81 | L 0-6 | 26-55 | 5 | 23,562 | J.P. Howell | Ryan Franklin | Ryan Franklin | J.P. Howell | | 336 | 457 | -121 |
| 2005-07-05 | vs SEA | 82 | W 8-6 | 27-55 | 5 | 10,658 | D.J. Carrasco | Gil Meche | D.J. Carrasco | Gil Meche | Mike MacDougal | 344 | 463 | -119 |
| 2005-07-06 | vs SEA | 83 | W 5-1 | 28-55 | 5 | 12,206 | Runelvys Hernandez | Aaron Sele | Runelvys Hernandez | Aaron Sele | Mike MacDougal | 349 | 464 | -115 |
| 2005-07-07 | vs MIN | 84 | W 8-5 | 29-55 | 5 | 12,662 | Jose Lima | Kyle Lohse | Jose Lima | Kyle Lohse | | 357 | 469 | -112 |
| 2005-07-08 | vs MIN | 85 | L 4-5 | 29-56 | 5 | 20,554 | Zack Greinke | Brad Radke | Brad Radke | Zack Greinke | Joe Nathan | 361 | 474 | -113 |
| 2005-07-09 | vs MIN | 86 | W 12-8 | 30-56 | 5 | 26,023 | J.P. Howell | Joe Mays | Leo Nunez | Jesse Crain | | 373 | 482 | -109 |
| 2005-07-10 | vs MIN | 87 | L 2-3 | 30-57 | 5 | 17,094 | D.J. Carrasco | Carlos Silva | J.C. Romero | Mike Wood | Jesse Crain | 375 | 485 | -110 |
| 2005-07-14 | @ DET | 88 | W 12-9 | 31-57 | 5 | 18,922 | Zack Greinke | Jeremy Bonderman | Zack Greinke | Jeremy Bonderman | Mike MacDougal | 387 | 494 | -107 |
| 2005-07-15 | @ DET | 89 | L 1-4 | 31-58 | 5 | 30,807 | Jose Lima | Nate Robertson | Nate Robertson | Jose Lima | Kyle Farnsworth | 388 | 498 | -110 |
| 2005-07-16 | @ DET | 90 | L 3-5 | 31-59 | 5 | 29,482 | J.P. Howell | Jason Johnson | Jason Johnson | Mike Wood | Kyle Farnsworth | 391 | 503 | -112 |
| 2005-07-17 | @ DET | 91 | W 5-0 | 32-59 | 5 | 24,166 | Runelvys Hernandez | Mike Maroth | Runelvys Hernandez | Mike Maroth | | 396 | 503 | -107 |
| 2005-07-18 | @ CLE | 92 | L 2-6 | 32-60 | 5 | 18,073 | D.J. Carrasco | Cliff Lee | Cliff Lee | D.J. Carrasco | | 398 | 509 | -111 |
| 2005-07-19 | @ CLE | 93 | W 4-0 | 33-60 | 5 | 20,862 | Zack Greinke | Kevin Millwood | Zack Greinke | Kevin Millwood | | 402 | 509 | -107 |
| 2005-07-20 | @ CLE | 94 | W 5-3 | 34-60 | 5 | 21,860 | Jose Lima | CC Sabathia | Jose Lima | CC Sabathia | Mike MacDougal | 407 | 512 | -105 |
| 2005-07-21 | @ CLE | 95 | L 1-10 | 34-61 | 5 | 24,694 | J.P. Howell | Jake Westbrook | Jake Westbrook | J.P. Howell | | 408 | 522 | -114 |
| 2005-07-22 | vs TOR | 96 | W 5-3 | 35-61 | 5 | 20,958 | Runelvys Hernandez | Pete Walker | Runelvys Hernandez | Pete Walker | Mike MacDougal | 413 | 525 | -112 |
| 2005-07-23 | vs TOR | 97 | L 4-9 | 35-62 | 5 | 26,626 | Kyle Snyder | David Bush | David Bush | Kyle Snyder | | 417 | 534 | -117 |
| 2005-07-24 | vs TOR | 98 | W 6-5 | 36-62 | 5 | 10,994 | D.J. Carrasco | Ted Lilly | D.J. Carrasco | Chad Gaudin | Mike MacDougal | 423 | 539 | -116 |
| 2005-07-25 | vs CHA | 99 | L 6-14 | 36-63 | 5 | 15,515 | Zack Greinke | Freddy Garcia | Freddy Garcia | Zack Greinke | | 429 | 553 | -124 |
| 2005-07-26 | vs CHA | 100 | W 7-1 | 37-63 | 5 | 19,175 | Jose Lima | Mark Buehrle | Jose Lima | Mark Buehrle | | 436 | 554 | -118 |
| 2005-07-27 | vs CHA | 101 | W 6-5 | 38-63 | 5 | 17,378 | Runelvys Hernandez | Jon Garland | Shawn Camp | Luis Vizcaino | | 442 | 559 | -117 |
| 2005-07-28 | @ TBA | 102 | L 5-10 | 38-64 | 5 | 8,308 | Kyle Snyder | Scott Kazmir | Scott Kazmir | Kyle Snyder | | 447 | 569 | -122 |
| 2005-07-29 | @ TBA | 103 | L 3-6 | 38-65 | 5 | 12,250 | D.J. Carrasco | Casey Fossum | Casey Fossum | D.J. Carrasco | Danys Baez | 450 | 575 | -125 |
| 2005-07-30 | @ TBA | 104 | L 3-7 | 38-66 | 5 | 11,940 | Zack Greinke | Doug Waechter | Doug Waechter | Zack Greinke | | 453 | 582 | -129 |
| 2005-07-31 | @ TBA | 105 | L 2-6 | 38-67 | 5 | 12,119 | Jose Lima | Mark Hendrickson | Mark Hendrickson | Jose Lima | | 455 | 588 | -133 |
| 2005-08-02 | @ BOS | 106 | L 4-6 | 38-68 | 5 | 35,386 | Runelvys Hernandez | Tim Wakefield | Tim Wakefield | Ambiorix Burgos | Curt Schilling | 459 | 594 | -135 |
| 2005-08-03 | @ BOS | 107 | L 5-8 | 38-69 | 5 | 35,055 | Kyle Snyder | Wade Miller | Wade Miller | Kyle Snyder | Curt Schilling | 464 | 602 | -138 |
| 2005-08-04 | @ BOS | 108 | L 9-11 | 38-70 | 5 | 35,060 | D.J. Carrasco | Matt Clement | Matt Clement | Leo Nunez | Curt Schilling | 473 | 613 | -140 |
| 2005-08-05 | vs OAK | 109 | L 4-5 | 38-71 | 5 | 23,979 | Zack Greinke | Kirk Saarloos | Joe Kennedy | Jeremy Affeldt | Huston Street | 477 | 618 | -141 |
| 2005-08-06 | vs OAK | 110 | L 1-16 | 38-72 | 5 | 19,964 | Jose Lima | Joe Blanton | Joe Blanton | Jose Lima | | 478 | 634 | -156 |
| 2005-08-07 | vs OAK | 111 | L 0-11 | 38-73 | 5 | 15,228 | Runelvys Hernandez | Dan Haren | Dan Haren | Runelvys Hernandez | | 478 | 645 | -167 |
| 2005-08-09 | vs CLE | 112 | L 7-13 | 38-74 | 5 | 15,182 | Mike Wood | Cliff Lee | Scott Sauerbeck | Mike MacDougal | | 485 | 658 | -173 |
| 2005-08-10 | vs CLE | 113 | L 1-6 | 38-75 | 5 | 16,061 | Zack Greinke | CC Sabathia | CC Sabathia | Zack Greinke | | 486 | 664 | -178 |
| 2005-08-11 | vs CLE | 114 | L 2-4 | 38-76 | 5 | 14,506 | D.J. Carrasco | Kevin Millwood | Kevin Millwood | D.J. Carrasco | Bob Wickman | 488 | 668 | -180 |
| 2005-08-14 | vs DET | 115 | L 7-8 | 38-78 | 5 | 0 | Mike Wood | Jason Johnson | Craig Dingman | Ambiorix Burgos | Fernando Rodney | 495 | 676 | -181 |
| 2005-08-14 | vs DET | 116 | L 0-1 | 38-78 | 5 | 17,568 | Jose Lima | Mike Maroth | Mike Maroth | Jose Lima | Fernando Rodney | 495 | 677 | -182 |
| 2005-08-15 | @ SEA | 117 | L 3-11 | 38-79 | 5 | 31,908 | Runelvys Hernandez | Felix Hernandez | Felix Hernandez | Runelvys Hernandez | | 498 | 688 | -190 |
| 2005-08-16 | @ SEA | 118 | L 3-4 | 38-80 | 5 | 31,425 | Zack Greinke | Joel Pineiro | Joel Pineiro | Jeremy Affeldt | Eddie Guardado | 501 | 692 | -191 |
| 2005-08-17 | @ SEA | 119 | L 5-11 | 38-81 | 5 | 35,224 | D.J. Carrasco | Jamie Moyer | Jamie Moyer | D.J. Carrasco | | 506 | 703 | -197 |
| 2005-08-19 | @ OAK | 120 | L 0-4 | 38-82 | 5 | 20,715 | Jose Lima | Rich Harden | Rich Harden | Jose Lima | Huston Street | 506 | 707 | -201 |
| 2005-08-20 | @ OAK | 121 | W 2-1 | 39-82 | 5 | 27,648 | Mike Wood | Barry Zito | Mike Wood | Barry Zito | Mike MacDougal | 508 | 708 | -200 |
| 2005-08-21 | @ OAK | 122 | W 5-4 | 40-82 | 5 | 25,834 | Runelvys Hernandez | Joe Blanton | Jimmy Gobble | Kiko Calero | | 513 | 712 | -199 |
| 2005-08-23 | vs BOS | 123 | L 2-5 | 40-83 | 5 | 21,323 | Zack Greinke | David Wells | David Wells | Zack Greinke | | 515 | 717 | -202 |
| 2005-08-24 | vs BOS | 124 | W 4-3 | 41-83 | 5 | 18,871 | D.J. Carrasco | Matt Clement | Andy Sisco | Bronson Arroyo | | 519 | 720 | -201 |
| 2005-08-25 | vs BOS | 125 | W 7-4 | 42-83 | 5 | 21,815 | Jose Lima | Curt Schilling | Jose Lima | Curt Schilling | Mike MacDougal | 526 | 724 | -198 |
| 2005-08-26 | @ NYA | 126 | L 1-5 | 42-84 | 5 | 53,922 | Mike Wood | Randy Johnson | Randy Johnson | Mike Wood | | 527 | 729 | -202 |
| 2005-08-27 | @ NYA | 127 | L 7-8 | 42-85 | 5 | 54,452 | J.P. Howell | Jaret Wright | Alan Embree | Shawn Camp | | 534 | 737 | -203 |
| 2005-08-28 | @ NYA | 128 | L 3-10 | 42-86 | 5 | 54,951 | Zack Greinke | Al Leiter | Al Leiter | Zack Greinke | | 537 | 747 | -210 |
| 2005-08-29 | vs MIN | 129 | L 1-3 | 42-87 | 5 | 13,555 | D.J. Carrasco | Scott Baker | Juan Rincon | Shawn Camp | Joe Nathan | 538 | 750 | -212 |
| 2005-08-30 | vs MIN | 130 | L 4-7 | 42-88 | 5 | 13,819 | Jose Lima | Carlos Silva | Carlos Silva | Jose Lima | Joe Nathan | 542 | 757 | -215 |
| 2005-08-31 | vs MIN | 131 | W 1-0 | 43-88 | 5 | 12,963 | Mike Wood | Kyle Lohse | Mike MacDougal | Matt Guerrier | | 543 | 757 | -214 |
| 2005-09-01 | vs TEX | 132 | L 4-5 | 43-89 | 5 | 12,735 | J.P. Howell | Kenny Rogers | Kenny Rogers | J.P. Howell | Francisco Cordero | 547 | 762 | -215 |
| 2005-09-02 | vs TEX | 133 | L 7-8 | 43-90 | 5 | 14,425 | Zack Greinke | Chris Young | Francisco Cordero | Mike MacDougal | John Wasdin | 554 | 770 | -216 |
| 2005-09-03 | vs TEX | 134 | L 3-5 | 43-91 | 5 | 18,932 | D.J. Carrasco | Juan Dominguez | Juan Dominguez | D.J. Carrasco | | 557 | 775 | -218 |
| 2005-09-04 | vs TEX | 135 | W 17-8 | 44-91 | 5 | 15,512 | Jimmy Gobble | Edinson Volquez | Leo Nunez | Edinson Volquez | | 574 | 783 | -209 |
| 2005-09-06 | @ CHA | 136 | L 5-6 | 44-92 | 5 | 14,571 | Jose Lima | Orlando Hernandez | Orlando Hernandez | Jose Lima | Dustin Hermanson | 579 | 789 | -210 |
| 2005-09-07 | @ CHA | 137 | L 0-1 | 44-93 | 5 | 18,513 | Mike Wood | Jose Contreras | Jose Contreras | Mike Wood | Dustin Hermanson | 579 | 790 | -211 |
| 2005-09-08 | @ CHA | 138 | W 4-2 | 45-93 | 5 | 17,701 | J.P. Howell | Freddy Garcia | J.P. Howell | Freddy Garcia | Mike MacDougal | 583 | 792 | -209 |
| 2005-09-09 | @ DET | 139 | W 12-2 | 46-93 | 5 | 23,950 | Zack Greinke | Sean Douglass | Zack Greinke | Sean Douglass | | 595 | 794 | -199 |
| 2005-09-10 | @ DET | 140 | L 3-4 | 46-94 | 5 | 25,242 | Jimmy Gobble | Mike Maroth | Chris Spurling | Andy Sisco | Fernando Rodney | 598 | 798 | -200 |
| 2005-09-11 | @ DET | 141 | L 4-14 | 46-95 | 5 | 20,559 | Jose Lima | Jason Johnson | Jason Johnson | Jose Lima | | 602 | 812 | -210 |
| 2005-09-13 | vs CHA | 142 | L 4-6 | 46-96 | 5 | 9,535 | Mike Wood | Jose Contreras | Jose Contreras | Mike Wood | Bobby Jenks | 606 | 818 | -212 |
| 2005-09-14 | vs CHA | 143 | W 10-9 | 47-96 | 5 | 9,922 | J.P. Howell | Freddy Garcia | Chris Demaria | Dustin Hermanson | | 616 | 827 | -211 |
| 2005-09-15 | vs CHA | 144 | W 7-5 | 48-96 | 5 | 9,258 | Zack Greinke | Mark Buehrle | Ambiorix Burgos | Mark Buehrle | Mike MacDougal | 623 | 832 | -209 |
| 2005-09-16 | @ CLE | 145 | L 1-3 | 48-97 | 5 | 21,975 | Jimmy Gobble | Scott Elarton | Scott Elarton | Jimmy Gobble | Bob Wickman | 624 | 835 | -211 |
| 2005-09-17 | @ CLE | 146 | L 4-5 | 48-98 | 5 | 32,392 | Runelvys Hernandez | Cliff Lee | Cliff Lee | Runelvys Hernandez | Bob Wickman | 628 | 840 | -212 |
| 2005-09-18 | @ CLE | 147 | L 0-11 | 48-99 | 5 | 22,654 | Jose Lima | CC Sabathia | CC Sabathia | Jose Lima | | 628 | 851 | -223 |
| 2005-09-19 | vs DET | 148 | W 10-4 | 49-99 | 5 | 8,915 | Mike Wood | Jeremy Bonderman | Mike Wood | Jeremy Bonderman | | 638 | 855 | -217 |
| 2005-09-20 | vs DET | 149 | W 5-4 | 51-99 | 5 | 0 | J.P. Howell | Mike Maroth | Mike MacDougal | Craig Dingman | | 643 | 859 | -216 |
| 2005-09-20 | vs DET | 150 | W 4-2 | 51-99 | 5 | 9,418 | Zack Greinke | Nate Robertson | Zack Greinke | Nate Robertson | Mike MacDougal | 647 | 861 | -214 |
| 2005-09-21 | vs DET | 151 | W 4-3 | 52-99 | 5 | 8,640 | Jimmy Gobble | Jason Johnson | Kyle Snyder | Fernando Rodney | | 651 | 864 | -213 |
| 2005-09-22 | vs CLE | 152 | L 6-11 | 52-100 | 5 | 10,028 | Runelvys Hernandez | Cliff Lee | Cliff Lee | Andy Sisco | Rafael Betancourt | 657 | 875 | -218 |
| 2005-09-23 | vs CLE | 153 | L 6-7 | 52-101 | 5 | 12,519 | Jose Lima | CC Sabathia | Bob Howry | Mike MacDougal | Bob Wickman | 663 | 882 | -219 |
| 2005-09-24 | vs CLE | 154 | L 4-11 | 52-102 | 5 | 17,358 | Mike Wood | Kevin Millwood | Kevin Millwood | Mike Wood | | 667 | 893 | -226 |
| 2005-09-25 | vs CLE | 155 | W 5-4 | 53-102 | 5 | 11,453 | Zack Greinke | Jake Westbrook | Mike MacDougal | Bob Howry | | 672 | 897 | -225 |
| 2005-09-26 | @ MIN | 156 | W 5-0 | 54-102 | 5 | 13,472 | J.P. Howell | Scott Baker | J.P. Howell | Scott Baker | | 677 | 897 | -220 |
| 2005-09-27 | @ MIN | 157 | L 1-3 | 54-103 | 5 | 16,147 | Runelvys Hernandez | Johan Santana | Johan Santana | Runelvys Hernandez | Joe Nathan | 678 | 900 | -222 |
| 2005-09-28 | @ MIN | 158 | L 3-6 | 54-104 | 5 | 14,982 | Jose Lima | Kyle Lohse | Jesse Crain | Andy Sisco | Joe Nathan | 681 | 906 | -225 |
| 2005-09-29 | @ MIN | 159 | W 10-6 | 55-104 | 5 | 14,638 | Mike Wood | Joe Mays | D.J. Carrasco | Travis Bowyer | | 691 | 912 | -221 |
| 2005-09-30 | @ TOR | 160 | L 1-10 | 55-105 | 5 | 23,381 | Zack Greinke | Josh Towers | Josh Towers | Zack Greinke | | 692 | 922 | -230 |
| 2005-10-01 | @ TOR | 161 | W 7-6 | 56-105 | 5 | 28,271 | J.P. Howell | David Bush | Ambiorix Burgos | Pete Walker | Mike MacDougal | 699 | 928 | -229 |
| 2005-10-02 | @ TOR | 162 | L 2-7 | 56-106 | 5 | 37,046 | Runelvys Hernandez | Gustavo Chacin | Gustavo Chacin | Runelvys Hernandez | | 701 | 935 | -234 |