| 1988-04-04 | @ OAK | 1 | L 1-4 | 0-1 | 6 | 45,333 | Mark Langston | Dave Stewart | Dave Stewart | Mark Langston | Dennis Eckersley | 1 | 4 | -3 |
| 1988-04-05 | @ OAK | 2 | L 0-6 | 0-2 | 6 | 14,005 | Mike Moore | Bob Welch | Bob Welch | Mike Moore | Dennis Eckersley | 1 | 10 | -9 |
| 1988-04-06 | @ OAK | 3 | W 6-5 | 1-2 | 5 | 18,536 | Steve Trout | Curt Young | Bill Swift | Gene Nelson | Julio Solano | 7 | 15 | -8 |
| 1988-04-08 | @ CHA | 4 | L 2-3 | 1-3 | 5 | 10,524 | Mike Campbell | Melido Perez | John Davis | Bill Wilkinson | | 9 | 18 | -9 |
| 1988-04-09 | @ CHA | 5 | W 3-2 | 2-3 | 4 | 15,826 | Mark Langston | Ricky Horton | Jerry Reed | Ricky Horton | | 12 | 20 | -8 |
| 1988-04-10 | @ CHA | 6 | W 7-4 | 3-3 | 4 | 16,814 | Mike Moore | Jerry Reuss | Mike Moore | Jerry Reuss | | 19 | 24 | -5 |
| 1988-04-12 | vs OAK | 7 | W 6-4 | 4-3 | 3 | 35,321 | Steve Trout | Gene Nelson | Steve Trout | Gene Nelson | Jerry Reed | 25 | 28 | -3 |
| 1988-04-13 | vs OAK | 8 | L 7-12 | 4-4 | 3 | 17,032 | Mike Campbell | Steve Ontiveros | Steve Ontiveros | Mike Campbell | Rick Honeycutt | 32 | 40 | -8 |
| 1988-04-14 | vs OAK | 9 | L 4-5 | 4-5 | 4 | 10,071 | Mark Langston | Dave Stewart | Dave Stewart | Jerry Reed | Dennis Eckersley | 36 | 45 | -9 |
| 1988-04-15 | vs CAL | 10 | L 3-5 | 4-6 | 6 | 10,976 | Mike Moore | Mike Witt | Mike Witt | Bill Wilkinson | | 39 | 50 | -11 |
| 1988-04-16 | vs CAL | 11 | W 7-6 | 5-6 | 6 | 24,771 | Bill Swift | Willie Fraser | Ed Nunez | DeWayne Buice | | 46 | 56 | -10 |
| 1988-04-17 | vs CAL | 12 | L 4-7 | 5-7 | 6 | 14,641 | Steve Trout | Kirk McCaskill | Kirk McCaskill | Steve Trout | Ray Krawczyk | 50 | 63 | -13 |
| 1988-04-18 | vs CHA | 13 | L 0-4 | 5-8 | 6 | 11,213 | Mike Campbell | Dave LaPoint | Dave LaPoint | Mike Campbell | | 50 | 67 | -17 |
| 1988-04-19 | vs CHA | 14 | L 2-7 | 5-9 | 6 | 7,652 | Mark Langston | Jerry Reuss | Jerry Reuss | Mark Langston | | 52 | 74 | -22 |
| 1988-04-20 | vs CHA | 15 | W 5-4 | 6-9 | 6 | 8,734 | Mike Moore | Ricky Horton | Mike Moore | Ricky Horton | | 57 | 78 | -21 |
| 1988-04-21 | @ CAL | 16 | L 6-11 | 6-10 | 6 | 22,172 | Bill Swift | Willie Fraser | Willie Fraser | Ed Nunez | | 63 | 89 | -26 |
| 1988-04-22 | @ CAL | 17 | W 7-4 | 7-10 | 5 | 26,206 | Steve Trout | Kirk McCaskill | Steve Trout | Kirk McCaskill | Bill Wilkinson | 70 | 93 | -23 |
| 1988-04-23 | @ CAL | 18 | W 11-4 | 8-10 | 4 | 27,136 | Mike Campbell | Dan Petry | Mike Campbell | Dan Petry | | 81 | 97 | -16 |
| 1988-04-24 | @ CAL | 19 | W 4-2 | 9-10 | 4 | 42,725 | Mark Langston | Chuck Finley | Mark Langston | Chuck Finley | | 85 | 99 | -14 |
| 1988-04-26 | @ CLE | 20 | L 6-12 | 9-11 | 4 | 6,690 | Mike Moore | Tom Candiotti | Tom Candiotti | Mike Moore | | 91 | 111 | -20 |
| 1988-04-27 | @ CLE | 21 | L 4-6 | 9-12 | 4 | 5,244 | Steve Trout | Greg Swindell | Greg Swindell | Steve Trout | Doug Jones | 95 | 117 | -22 |
| 1988-04-28 | @ CLE | 22 | W 3-1 | 10-12 | 4 | 3,762 | Mike Campbell | John Farrell | Mike Campbell | John Farrell | | 98 | 118 | -20 |
| 1988-04-29 | @ DET | 23 | L 6-9 | 10-13 | 4 | 13,757 | Mark Langston | Jack Morris | Guillermo Hernandez | Mark Langston | Don Heinkel | 104 | 127 | -23 |
| 1988-04-30 | @ DET | 24 | L 3-4 | 10-14 | 5 | 17,505 | Bill Swift | Walt Terrell | Paul Gibson | Michael Jackson | | 107 | 131 | -24 |
| 1988-05-01 | @ DET | 25 | L 2-3 | 10-15 | 7 | 28,432 | Mike Moore | Jeff Robinson | Jeff Robinson | Mike Moore | Guillermo Hernandez | 109 | 134 | -25 |
| 1988-05-02 | vs TOR | 26 | W 7-5 | 11-15 | 4 | 13,197 | Steve Trout | Mike Flanagan | Steve Trout | Mike Flanagan | Julio Solano | 116 | 139 | -23 |
| 1988-05-03 | vs TOR | 27 | L 2-9 | 11-16 | 6 | 9,970 | Mike Campbell | Todd Stottlemyre | Todd Stottlemyre | Mike Campbell | Duane Ward | 118 | 148 | -30 |
| 1988-05-04 | vs CLE | 28 | W 5-4 | 12-16 | 4 | 7,213 | Mark Langston | Scott Bailes | Mark Langston | Scott Bailes | Julio Solano | 123 | 152 | -29 |
| 1988-05-05 | vs CLE | 29 | W 7-2 | 13-16 | 4 | 6,590 | Bill Swift | Rich Yett | Bill Swift | Rich Yett | | 130 | 154 | -24 |
| 1988-05-06 | vs DET | 30 | L 4-8 | 13-17 | 4 | 16,667 | Mike Moore | Jeff Robinson | Jeff Robinson | Dennis Powell | Mike Henneman | 134 | 162 | -28 |
| 1988-05-07 | vs DET | 31 | W 7-6 | 14-17 | 4 | 27,019 | Steve Trout | Doyle Alexander | Dennis Powell | Paul Gibson | Bill Wilkinson | 141 | 168 | -27 |
| 1988-05-08 | vs DET | 32 | L 3-9 | 14-18 | 5 | 12,695 | Mike Campbell | Frank Tanana | Frank Tanana | Mike Campbell | | 144 | 177 | -33 |
| 1988-05-10 | @ TOR | 33 | W 4-2 | 15-18 | 5 | 28,290 | Mark Langston | Jim Clancy | Mark Langston | Jim Clancy | | 148 | 179 | -31 |
| 1988-05-11 | @ TOR | 34 | L 3-9 | 15-19 | 5 | 27,575 | Mike Moore | Dave Stieb | Dave Stieb | Mike Moore | | 151 | 188 | -37 |
| 1988-05-12 | @ TOR | 35 | L 2-8 | 15-20 | 5 | 30,334 | Bill Swift | Mike Flanagan | Mike Flanagan | Bill Swift | | 153 | 196 | -43 |
| 1988-05-13 | @ BOS | 36 | L 8-14 | 15-21 | 5 | 29,582 | Mike Campbell | Oil Can Boyd | Oil Can Boyd | Mike Campbell | Wes Gardner | 161 | 210 | -49 |
| 1988-05-14 | @ BOS | 37 | L 0-3 | 15-22 | 6 | 33,846 | Scott Bankhead | Roger Clemens | Roger Clemens | Scott Bankhead | | 161 | 213 | -52 |
| 1988-05-15 | @ BOS | 38 | W 11-7 | 16-22 | 6 | 33,109 | Mark Langston | Bruce Hurst | Michael Jackson | Lee Smith | | 172 | 220 | -48 |
| 1988-05-16 | @ NYA | 39 | L 1-3 | 16-23 | 6 | 17,651 | Mike Moore | John Candelaria | John Candelaria | Mike Moore | Dave Righetti | 173 | 223 | -50 |
| 1988-05-17 | @ NYA | 40 | W 6-2 | 17-23 | 6 | 17,858 | Bill Swift | Richard Dotson | Bill Swift | Richard Dotson | | 179 | 225 | -46 |
| 1988-05-20 | @ BAL | 41 | W 3-2 | 18-23 | 5 | 13,142 | Mark Langston | Mark Williamson | Mark Langston | Mark Williamson | Michael Jackson | 182 | 227 | -45 |
| 1988-05-21 | @ BAL | 42 | L 1-3 | 18-24 | 5 | 20,079 | Scott Bankhead | Jeff Ballard | Jeff Ballard | Dennis Powell | Tom Niedenfuer | 183 | 230 | -47 |
| 1988-05-22 | @ BAL | 43 | L 2-7 | 18-25 | 6 | 24,650 | Mike Moore | Jose Bautista | Jose Bautista | Mike Moore | Mike Morgan | 185 | 237 | -52 |
| 1988-05-23 | vs BOS | 44 | W 14-3 | 19-25 | 6 | 15,511 | Bill Swift | Oil Can Boyd | Bill Swift | Oil Can Boyd | | 199 | 240 | -41 |
| 1988-05-24 | vs BOS | 45 | W 14-1 | 20-25 | 5 | 9,473 | Mike Campbell | Mike Smithson | Mike Campbell | Mike Smithson | | 213 | 241 | -28 |
| 1988-05-25 | vs BOS | 46 | L 0-4 | 20-26 | 5 | 17,968 | Mark Langston | Roger Clemens | Roger Clemens | Mark Langston | | 213 | 245 | -32 |
| 1988-05-27 | vs NYA | 47 | L 1-5 | 20-27 | 5 | 19,933 | Scott Bankhead | Tommy John | Tommy John | Scott Bankhead | Cecilio Guante | 214 | 250 | -36 |
| 1988-05-28 | vs NYA | 48 | W 6-1 | 21-27 | 5 | 33,449 | Bill Swift | Rick Rhoden | Bill Swift | Rick Rhoden | | 220 | 251 | -31 |
| 1988-05-29 | vs NYA | 49 | L 3-7 | 21-28 | 5 | 26,931 | Mike Campbell | John Candelaria | John Candelaria | Mike Campbell | Cecilio Guante | 223 | 258 | -35 |
| 1988-05-30 | vs BAL | 50 | W 4-1 | 22-28 | 5 | 9,309 | Mark Langston | Jay Tibbs | Mark Langston | Jay Tibbs | Rod Scurry | 227 | 259 | -32 |
| 1988-05-31 | vs BAL | 51 | L 5-12 | 22-29 | 6 | 7,371 | Ed Nunez | Mike Morgan | Dave J. Schmidt | Ed Nunez | | 232 | 271 | -39 |
| 1988-06-01 | vs BAL | 52 | W 4-3 | 23-29 | 5 | 8,137 | Scott Bankhead | Jeff Ballard | Michael Jackson | Jeff Ballard | Rod Scurry | 236 | 274 | -38 |
| 1988-06-02 | @ KCA | 53 | L 0-3 | 23-30 | 5 | 24,546 | Bill Swift | Ted Power | Ted Power | Bill Swift | | 236 | 277 | -41 |
| 1988-06-03 | @ KCA | 54 | L 1-3 | 23-31 | 5 | 34,163 | Mike Campbell | Bret Saberhagen | Bret Saberhagen | Mike Campbell | | 237 | 280 | -43 |
| 1988-06-04 | @ KCA | 55 | L 3-4 | 23-32 | 6 | 33,394 | Mark Langston | Charlie Leibrandt | Steve Farr | Mark Langston | | 240 | 284 | -44 |
| 1988-06-05 | @ KCA | 56 | L 3-7 | 23-33 | 6 | 27,601 | Ed Nunez | Mark Gubicza | Mark Gubicza | Ed Nunez | | 243 | 291 | -48 |
| 1988-06-06 | vs MIL | 57 | W 2-0 | 24-33 | 6 | 13,867 | Scott Bankhead | Don August | Scott Bankhead | Don August | Mike Moore | 245 | 291 | -46 |
| 1988-06-07 | vs MIL | 58 | W 5-4 | 25-33 | 6 | 7,209 | Bill Swift | Bill Wegman | Mike Moore | Paul Mirabella | | 250 | 295 | -45 |
| 1988-06-08 | vs MIL | 59 | L 7-8 | 25-34 | 6 | 7,477 | Mike Campbell | Tom Filer | Mark Clear | Michael Jackson | Dan Plesac | 257 | 303 | -46 |
| 1988-06-09 | vs MIN | 60 | L 5-7 | 25-35 | 6 | 9,506 | Mark Langston | Bert Blyleven | Bert Blyleven | Mark Langston | Jeff Reardon | 262 | 310 | -48 |
| 1988-06-10 | vs MIN | 61 | L 1-3 | 25-36 | 6 | 19,605 | Ed Nunez | Allan Anderson | Allan Anderson | Ed Nunez | Jeff Reardon | 263 | 313 | -50 |
| 1988-06-11 | vs MIN | 62 | W 3-2 | 26-36 | 6 | 20,209 | Scott Bankhead | Frank Viola | Michael Jackson | Frank Viola | Mike Schooler | 266 | 315 | -49 |
| 1988-06-12 | vs MIN | 63 | L 2-6 | 26-37 | 6 | 23,650 | Bill Swift | Charlie Lea | Charlie Lea | Bill Swift | | 268 | 321 | -53 |
| 1988-06-13 | @ MIL | 64 | L 1-3 | 26-38 | 6 | 14,132 | Mike Campbell | Bill Wegman | Bill Wegman | Mike Campbell | Dan Plesac | 269 | 324 | -55 |
| 1988-06-14 | @ MIL | 65 | L 1-5 | 26-39 | 6 | 12,539 | Mike Moore | Tom Filer | Tom Filer | Mike Moore | | 270 | 329 | -59 |
| 1988-06-15 | @ MIL | 66 | L 1-5 | 26-40 | 6 | 22,246 | Mark Langston | Teddy Higuera | Teddy Higuera | Mark Langston | Dan Plesac | 271 | 334 | -63 |
| 1988-06-17 | @ MIN | 67 | L 1-4 | 26-41 | 7 | 35,226 | Scott Bankhead | Frank Viola | Frank Viola | Scott Bankhead | Jeff Reardon | 272 | 338 | -66 |
| 1988-06-18 | @ MIN | 68 | L 2-6 | 26-42 | 7 | 40,561 | Bill Swift | Charlie Lea | Charlie Lea | Bill Swift | Jeff Reardon | 274 | 344 | -70 |
| 1988-06-19 | @ MIN | 69 | L 1-3 | 26-43 | 7 | 36,164 | Mike Moore | Bert Blyleven | Bert Blyleven | Mike Moore | Jeff Reardon | 275 | 347 | -72 |
| 1988-06-20 | @ TEX | 70 | L 3-4 | 26-44 | 7 | 20,919 | Mark Langston | Jeff Russell | Jeff Russell | Mike Schooler | | 278 | 351 | -73 |
| 1988-06-21 | @ TEX | 71 | L 0-6 | 26-45 | 7 | 10,918 | Steve Trout | Paul Kilgus | Paul Kilgus | Steve Trout | | 278 | 357 | -79 |
| 1988-06-22 | @ TEX | 72 | W 3-2 | 27-45 | 7 | 24,650 | Scott Bankhead | Jose Guzman | Mike Schooler | Jose Guzman | | 281 | 359 | -78 |
| 1988-06-24 | vs KCA | 73 | W 7-0 | 28-45 | 7 | 11,167 | Mike Moore | Floyd Bannister | Mike Moore | Floyd Bannister | | 288 | 359 | -71 |
| 1988-06-25 | vs KCA | 74 | L 3-7 | 28-46 | 7 | 13,289 | Mark Langston | Bret Saberhagen | Bret Saberhagen | Mark Langston | | 291 | 366 | -75 |
| 1988-06-26 | vs KCA | 75 | W 8-0 | 29-46 | 7 | 11,668 | Bill Swift | Charlie Leibrandt | Bill Swift | Charlie Leibrandt | | 299 | 366 | -67 |
| 1988-06-27 | vs TEX | 76 | W 6-3 | 30-46 | 7 | 7,591 | Scott Bankhead | Paul Kilgus | Scott Bankhead | Paul Kilgus | Mike Schooler | 305 | 369 | -64 |
| 1988-06-28 | vs TEX | 77 | L 0-6 | 30-47 | 7 | 8,605 | Steve Trout | Jose Guzman | Jose Guzman | Steve Trout | | 305 | 375 | -70 |
| 1988-06-29 | vs TEX | 78 | L 0-1 | 30-48 | 7 | 8,487 | Mike Moore | Charlie Hough | Charlie Hough | Mike Schooler | Mitch Williams | 305 | 376 | -71 |
| 1988-07-01 | @ CLE | 79 | W 11-3 | 31-48 | 7 | 45,785 | Mark Langston | Greg Swindell | Mark Langston | Greg Swindell | Michael Jackson | 316 | 379 | -63 |
| 1988-07-02 | @ CLE | 80 | L 7-10 | 31-49 | 7 | 18,096 | Bill Swift | John Farrell | John Farrell | Bill Swift | Doug Jones | 323 | 389 | -66 |
| 1988-07-03 | @ CLE | 81 | W 7-6 | 32-49 | 7 | 19,397 | Scott Bankhead | Buddy Black | Scott Bankhead | Jon Perlman | Mike Schooler | 330 | 395 | -65 |
| 1988-07-04 | @ DET | 82 | L 3-5 | 32-50 | 7 | 19,710 | Mike Moore | Frank Tanana | Mike Henneman | Rod Scurry | Eric King | 333 | 400 | -67 |
| 1988-07-05 | @ DET | 83 | W 5-4 | 33-50 | 7 | 17,185 | Steve Trout | Walt Terrell | Steve Trout | Walt Terrell | Mike Schooler | 338 | 404 | -66 |
| 1988-07-06 | @ DET | 84 | L 6-7 | 33-51 | 7 | 18,298 | Mark Langston | Doyle Alexander | Mike Henneman | Mike Schooler | | 344 | 411 | -67 |
| 1988-07-08 | @ TOR | 85 | L 2-3 | 33-52 | 7 | 30,247 | Bill Swift | Mike Flanagan | Mike Flanagan | Bill Swift | Duane Ward | 346 | 414 | -68 |
| 1988-07-09 | @ TOR | 86 | W 9-3 | 34-52 | 7 | 31,373 | Scott Bankhead | Todd Stottlemyre | Scott Bankhead | Todd Stottlemyre | | 355 | 417 | -62 |
| 1988-07-10 | @ TOR | 87 | L 0-5 | 34-53 | 7 | 35,323 | Mike Moore | Jimmy Key | Jimmy Key | Mike Moore | | 355 | 422 | -67 |
| 1988-07-14 | vs CLE | 88 | W 3-1 | 35-53 | 7 | 9,277 | Mark Langston | Greg Swindell | Mark Langston | Greg Swindell | | 358 | 423 | -65 |
| 1988-07-15 | vs CLE | 89 | W 8-5 | 36-53 | 7 | 9,593 | Mike Moore | John Farrell | Michael Jackson | Brad Havens | Mike Schooler | 366 | 428 | -62 |
| 1988-07-16 | vs CLE | 90 | L 2-8 | 36-54 | 7 | 17,761 | Scott Bankhead | Buddy Black | Buddy Black | Scott Bankhead | Doug Jones | 368 | 436 | -68 |
| 1988-07-17 | vs CLE | 91 | L 4-7 | 36-55 | 7 | 9,779 | Bill Swift | Tom Candiotti | Don Gordon | Bill Swift | Doug Jones | 372 | 443 | -71 |
| 1988-07-18 | vs DET | 92 | L 3-12 | 36-56 | 7 | 13,613 | Steve Trout | Walt Terrell | Walt Terrell | Steve Trout | | 375 | 455 | -80 |
| 1988-07-19 | vs DET | 93 | W 9-6 | 37-56 | 7 | 10,647 | Mark Langston | Jack Morris | Michael Jackson | Jack Morris | Mike Schooler | 384 | 461 | -77 |
| 1988-07-20 | vs DET | 94 | L 5-12 | 37-57 | 7 | 10,959 | Mike Moore | Doyle Alexander | Doyle Alexander | Mike Moore | | 389 | 473 | -84 |
| 1988-07-21 | vs TOR | 95 | W 6-2 | 38-57 | 7 | 9,024 | Scott Bankhead | Dave Stieb | Scott Bankhead | Dave Stieb | Mike Schooler | 395 | 475 | -80 |
| 1988-07-22 | vs TOR | 96 | W 10-9 | 39-57 | 7 | 10,506 | Bill Swift | Todd Stottlemyre | Mike Schooler | Tom Henke | | 405 | 484 | -79 |
| 1988-07-23 | vs TOR | 97 | L 2-5 | 39-58 | 7 | 17,979 | Steve Trout | Jeff Musselman | Jeff Musselman | Steve Trout | | 407 | 489 | -82 |
| 1988-07-24 | vs TOR | 98 | L 0-6 | 39-59 | 7 | 10,487 | Mark Langston | Mike Flanagan | Mike Flanagan | Mark Langston | | 407 | 495 | -88 |
| 1988-07-25 | @ CHA | 99 | L 5-6 | 39-60 | 7 | 11,434 | Mike Moore | Jerry Reuss | Jerry Reuss | Mike Moore | Bobby Thigpen | 412 | 501 | -89 |
| 1988-07-26 | @ CHA | 100 | L 0-1 | 39-61 | 7 | 11,551 | Scott Bankhead | Jack McDowell | Ricky Horton | Mike Schooler | | 412 | 502 | -90 |
| 1988-07-27 | @ CHA | 101 | L 1-6 | 39-62 | 7 | 15,033 | Bill Swift | Melido Perez | Melido Perez | Bill Swift | | 413 | 508 | -95 |
| 1988-07-29 | vs OAK | 102 | W 5-3 | 40-62 | 7 | 14,685 | Mark Langston | Bob Welch | Michael Jackson | Dennis Eckersley | | 418 | 511 | -93 |
| 1988-07-30 | vs OAK | 103 | L 2-5 | 40-63 | 7 | 19,787 | Mike Moore | Dave Stewart | Dave Stewart | Mike Moore | | 420 | 516 | -96 |
| 1988-07-31 | vs OAK | 104 | L 2-6 | 40-64 | 7 | 12,930 | Scott Bankhead | Storm Davis | Storm Davis | Scott Bankhead | Greg Cadaret | 422 | 522 | -100 |
| 1988-08-01 | vs CAL | 105 | L 4-8 | 40-65 | 7 | 11,584 | Bill Swift | Terry Clark | Terry Clark | Bill Swift | | 426 | 530 | -104 |
| 1988-08-02 | vs CAL | 106 | L 2-10 | 40-66 | 7 | 8,565 | Steve Trout | Chuck Finley | Chuck Finley | Steve Trout | | 428 | 540 | -112 |
| 1988-08-03 | vs CAL | 107 | W 8-7 | 41-66 | 7 | 9,574 | Mark Langston | Kirk McCaskill | Mike Schooler | Bryan Harvey | | 436 | 547 | -111 |
| 1988-08-04 | @ OAK | 108 | L 0-2 | 41-67 | 7 | 18,313 | Mike Moore | Dave Stewart | Dave Stewart | Mike Moore | | 436 | 549 | -113 |
| 1988-08-05 | @ OAK | 109 | L 1-4 | 41-68 | 7 | 19,318 | Scott Bankhead | Storm Davis | Storm Davis | Scott Bankhead | Dennis Eckersley | 437 | 553 | -116 |
| 1988-08-06 | @ OAK | 110 | L 4-5 | 41-69 | 7 | 30,574 | Bill Swift | Todd Burns | Gene Nelson | Michael Jackson | | 441 | 558 | -117 |
| 1988-08-07 | @ OAK | 111 | W 12-7 | 42-69 | 7 | 24,351 | Dennis Powell | Jim Corsi | Mike Schooler | Eric Plunk | | 453 | 565 | -112 |
| 1988-08-08 | @ CAL | 112 | W 4-3 | 43-69 | 7 | 23,506 | Mark Langston | Kirk McCaskill | Mark Langston | Kirk McCaskill | Mike Schooler | 457 | 568 | -111 |
| 1988-08-09 | @ CAL | 113 | W 4-1 | 44-69 | 7 | 24,617 | Mike Moore | Mike Witt | Mike Moore | Mike Witt | Michael Jackson | 461 | 569 | -108 |
| 1988-08-10 | @ CAL | 114 | L 1-2 | 44-70 | 7 | 24,653 | Scott Bankhead | Willie Fraser | Willie Fraser | Scott Bankhead | | 462 | 571 | -109 |
| 1988-08-11 | vs CHA | 115 | L 3-4 | 44-71 | 7 | 9,056 | Bill Swift | Jerry Reuss | Jerry Reuss | Michael Jackson | Bobby Thigpen | 465 | 575 | -110 |
| 1988-08-12 | vs CHA | 116 | L 2-7 | 44-72 | 7 | 9,065 | Dennis Powell | Dave LaPoint | Dave LaPoint | Dennis Powell | | 467 | 582 | -115 |
| 1988-08-13 | vs CHA | 117 | L 4-7 | 44-73 | 7 | 10,078 | Mark Langston | Melido Perez | Melido Perez | Mark Langston | Ricky Horton | 471 | 589 | -118 |
| 1988-08-14 | vs CHA | 118 | W 11-0 | 45-73 | 7 | 11,994 | Mike Moore | Bill Long | Mike Moore | Bill Long | | 482 | 589 | -107 |
| 1988-08-16 | @ BOS | 119 | W 7-0 | 46-73 | 7 | 33,924 | Scott Bankhead | Wes Gardner | Scott Bankhead | Wes Gardner | | 489 | 589 | -100 |
| 1988-08-17 | @ BOS | 120 | L 2-7 | 46-74 | 7 | 31,548 | Bill Swift | Bruce Hurst | Bruce Hurst | Bill Swift | | 491 | 596 | -105 |
| 1988-08-18 | @ BOS | 121 | W 6-1 | 47-74 | 7 | 33,944 | Mark Langston | Mike Boddicker | Mark Langston | Mike Boddicker | | 497 | 597 | -100 |
| 1988-08-19 | @ NYA | 122 | L 3-5 | 48-75 | 7 | 0 | Terry Taylor | John Candelaria | Dave Righetti | Mike Schooler | | 500 | 602 | -102 |
| 1988-08-19 | @ NYA | 123 | W 6-1 | 48-75 | 7 | 32,057 | Mike Moore | Richard Dotson | Mike Moore | Richard Dotson | | 506 | 603 | -97 |
| 1988-08-20 | @ NYA | 124 | W 9-5 | 49-75 | 7 | 39,086 | Mike Campbell | Scott Nielsen | Mike Campbell | Scott Nielsen | | 515 | 608 | -93 |
| 1988-08-21 | @ NYA | 125 | W 4-2 | 50-75 | 7 | 42,293 | Scott Bankhead | Rick Rhoden | Scott Bankhead | Rick Rhoden | Mike Schooler | 519 | 610 | -91 |
| 1988-08-22 | @ BAL | 126 | W 7-3 | 51-75 | 7 | 15,036 | Bill Swift | Oswaldo Peraza | Bill Wilkinson | Oswaldo Peraza | | 526 | 613 | -87 |
| 1988-08-24 | @ BAL | 127 | L 3-4 | 51-77 | 7 | 0 | Mark Langston | Jeff Ballard | Mark Williamson | Mike Schooler | | 529 | 617 | -88 |
| 1988-08-24 | @ BAL | 128 | L 3-4 | 51-77 | 7 | 15,611 | Mike Moore | Dave J. Schmidt | Tom Niedenfuer | Rod Scurry | | 532 | 621 | -89 |
| 1988-08-26 | vs BOS | 129 | L 3-5 | 51-78 | 7 | 16,109 | Scott Bankhead | Oil Can Boyd | Oil Can Boyd | Scott Bankhead | Lee Smith | 535 | 626 | -91 |
| 1988-08-27 | vs BOS | 130 | W 8-6 | 52-78 | 7 | 19,706 | Terry Taylor | Wes Gardner | Bill Wilkinson | Tom Bolton | Mike Schooler | 543 | 632 | -89 |
| 1988-08-28 | vs BOS | 131 | L 2-7 | 52-79 | 7 | 17,047 | Mike Moore | Bruce Hurst | Bruce Hurst | Mike Moore | | 545 | 639 | -94 |
| 1988-08-29 | vs NYA | 132 | W 9-6 | 53-79 | 7 | 14,963 | Mark Langston | Scott Nielsen | Mark Langston | Scott Nielsen | | 554 | 645 | -91 |
| 1988-08-30 | vs NYA | 133 | W 7-1 | 54-79 | 7 | 13,065 | Mike Campbell | Richard Dotson | Mike Campbell | Richard Dotson | | 561 | 646 | -85 |
| 1988-08-31 | vs NYA | 134 | L 1-4 | 54-80 | 7 | 13,567 | Scott Bankhead | Rick Rhoden | Rick Rhoden | Scott Bankhead | | 562 | 650 | -88 |
| 1988-09-02 | vs BAL | 135 | L 3-4 | 54-81 | 7 | 7,372 | Mike Moore | Oswaldo Peraza | Gregg Olson | Mike Schooler | Tom Niedenfuer | 565 | 654 | -89 |
| 1988-09-03 | vs BAL | 136 | W 1-0 | 55-81 | 7 | 8,644 | Mark Langston | Jose Bautista | Mark Langston | Jose Bautista | | 566 | 654 | -88 |
| 1988-09-04 | vs BAL | 137 | L 4-6 | 55-82 | 7 | 6,503 | Terry Taylor | Jeff Ballard | Mark Williamson | Terry Taylor | Tom Niedenfuer | 570 | 660 | -90 |
| 1988-09-05 | @ MIN | 138 | L 0-2 | 55-83 | 7 | 31,133 | Erik Hanson | Frank Viola | Frank Viola | Erik Hanson | Jeff Reardon | 570 | 662 | -92 |
| 1988-09-06 | @ MIN | 139 | W 8-3 | 56-83 | 7 | 17,185 | Mike Campbell | Bert Blyleven | Mike Campbell | Bert Blyleven | Mike Schooler | 578 | 665 | -87 |
| 1988-09-07 | @ MIN | 140 | W 2-1 | 57-83 | 7 | 27,288 | Mike Moore | Allan Anderson | Bill Swift | Dan Schatzeder | | 580 | 666 | -86 |
| 1988-09-09 | @ MIL | 141 | L 1-2 | 57-84 | 7 | 16,149 | Mark Langston | Bill Wegman | Chris Bosio | Mark Langston | | 581 | 668 | -87 |
| 1988-09-10 | @ MIL | 142 | W 1-0 | 58-84 | 7 | 48,973 | Erik Hanson | Teddy Higuera | Erik Hanson | Teddy Higuera | Mike Schooler | 582 | 668 | -86 |
| 1988-09-11 | @ MIL | 143 | L 3-5 | 58-85 | 7 | 21,894 | Mike Campbell | Don August | Don August | Mike Campbell | Dan Plesac | 585 | 673 | -88 |
| 1988-09-12 | vs MIN | 144 | W 3-1 | 59-85 | 7 | 8,621 | Mike Moore | Allan Anderson | Mike Moore | Allan Anderson | | 588 | 674 | -86 |
| 1988-09-13 | vs MIN | 145 | L 1-2 | 59-86 | 7 | 7,469 | Terry Taylor | Les Straker | Keith Atherton | Bill Swift | Jeff Reardon | 589 | 676 | -87 |
| 1988-09-14 | vs MIN | 146 | W 2-0 | 60-86 | 7 | 7,130 | Mark Langston | Freddie Toliver | Mark Langston | Freddie Toliver | Mike Schooler | 591 | 676 | -85 |
| 1988-09-16 | vs MIL | 147 | L 1-5 | 60-87 | 7 | 7,497 | Erik Hanson | Don August | Don August | Erik Hanson | | 592 | 681 | -89 |
| 1988-09-17 | vs MIL | 148 | W 11-0 | 61-87 | 7 | 9,644 | Mike Moore | Mike Birkbeck | Mike Moore | Mike Birkbeck | | 603 | 681 | -78 |
| 1988-09-18 | vs MIL | 149 | L 2-10 | 61-88 | 7 | 7,937 | Mike Campbell | Juan Nieves | Juan Nieves | Mike Campbell | | 605 | 691 | -86 |
| 1988-09-19 | vs KCA | 150 | W 4-0 | 62-88 | 7 | 6,557 | Mark Langston | Floyd Bannister | Mark Langston | Floyd Bannister | | 609 | 691 | -82 |
| 1988-09-20 | vs KCA | 151 | W 11-10 | 63-88 | 7 | 6,916 | Terry Taylor | Charlie Leibrandt | Mike Schooler | Jerry Gleaton | | 620 | 701 | -81 |
| 1988-09-21 | vs KCA | 152 | L 4-5 | 63-89 | 7 | 7,382 | Erik Hanson | Mark Gubicza | Mark Gubicza | Michael Jackson | Israel Sanchez | 624 | 706 | -82 |
| 1988-09-23 | @ TEX | 153 | L 2-3 | 63-90 | 7 | 11,143 | Mike Moore | Charlie Hough | Charlie Hough | Mike Schooler | | 626 | 709 | -83 |
| 1988-09-24 | @ TEX | 154 | W 3-0 | 64-90 | 7 | 13,219 | Mark Langston | Jeff Russell | Mark Langston | Jeff Russell | | 629 | 709 | -80 |
| 1988-09-25 | @ TEX | 155 | W 8-5 | 65-90 | 7 | 14,349 | Mike Campbell | Kevin Brown | Gene Walter | Craig McMurtry | Mike Schooler | 637 | 714 | -77 |
| 1988-09-26 | @ KCA | 156 | L 0-5 | 65-91 | 7 | 19,122 | Bill Swift | Mark Gubicza | Mark Gubicza | Bill Swift | | 637 | 719 | -82 |
| 1988-09-27 | @ KCA | 157 | W 10-3 | 66-91 | 7 | 17,463 | Erik Hanson | Tom Gordon | Erik Hanson | Tom Gordon | Michael Jackson | 647 | 722 | -75 |
| 1988-09-29 | vs TEX | 158 | W 5-1 | 67-91 | 7 | 6,836 | Mark Langston | Jeff Russell | Mark Langston | Jeff Russell | Mike Schooler | 652 | 723 | -71 |
| 1988-09-30 | vs TEX | 159 | L 6-11 | 67-92 | 7 | 7,870 | Mike Moore | Kevin Brown | Craig McMurtry | Mike Moore | | 658 | 734 | -76 |
| 1988-10-01 | vs TEX | 160 | W 4-3 | 68-92 | 7 | 19,706 | Mike Campbell | Bobby Witt | Bill Swift | Dwayne Henry | | 662 | 737 | -75 |
| 1988-10-02 | vs TEX | 161 | L 2-7 | 68-93 | 7 | 8,696 | Erik Hanson | Paul Kilgus | Paul Kilgus | Erik Hanson | Craig McMurtry | 664 | 744 | -80 |