| 1998-04-01 | @ OAK | 1 | W 2-0 | 1-0 | 1 | 36,915 | Pedro Martinez | Tom Candiotti | Pedro Martinez | Tom Candiotti | Tom Gordon | 2 | 0 | 2 |
| 1998-04-02 | @ OAK | 2 | W 6-3 | 2-0 | 1 | 7,313 | Tim Wakefield | Kenny Rogers | John Wasdin | Billy Taylor | Tom Gordon | 8 | 3 | 5 |
| 1998-04-03 | @ SEA | 3 | L 6-11 | 2-1 | 2 | 27,555 | Derek Lowe | Ken Cloude | Ken Cloude | Derek Lowe | | 14 | 14 | 0 |
| 1998-04-04 | @ SEA | 4 | L 6-12 | 2-2 | 3 | 43,035 | Brian Rose | Bill Swift | Bill Swift | Brian Rose | | 20 | 26 | -6 |
| 1998-04-05 | @ SEA | 5 | W 10-5 | 3-2 | 3 | 35,143 | Bret Saberhagen | Randy Johnson | Bret Saberhagen | Randy Johnson | | 30 | 31 | -1 |
| 1998-04-06 | @ ANA | 6 | L 1-2 | 3-3 | 3 | 21,352 | Pedro Martinez | Chuck Finley | Mike Holtz | Tom Gordon | | 31 | 33 | -2 |
| 1998-04-07 | @ ANA | 7 | L 1-6 | 3-4 | 3 | 19,926 | Tim Wakefield | Ken Hill | Ken Hill | Tim Wakefield | | 32 | 39 | -7 |
| 1998-04-08 | @ ANA | 8 | L 1-2 | 3-5 | 5 | 24,450 | Derek Lowe | Jack McDowell | Jack McDowell | Derek Lowe | Troy Percival | 33 | 41 | -8 |
| 1998-04-10 | vs SEA | 9 | W 9-7 | 4-5 | 4 | 32,805 | Brian Rose | Randy Johnson | Rich Garces | Mike Timlin | | 42 | 48 | -6 |
| 1998-04-11 | vs SEA | 10 | W 5-0 | 5-5 | 4 | 32,403 | Pedro Martinez | Jamie Moyer | Pedro Martinez | Jamie Moyer | | 47 | 48 | -1 |
| 1998-04-12 | vs SEA | 11 | W 8-7 | 6-5 | 4 | 23,270 | Tim Wakefield | Jeff Fassero | John Wasdin | Heathcliff Slocumb | | 55 | 55 | 0 |
| 1998-04-13 | vs OAK | 12 | W 6-3 | 7-5 | 4 | 18,011 | Bret Saberhagen | Kenny Rogers | Bret Saberhagen | Kenny Rogers | Tom Gordon | 61 | 58 | 3 |
| 1998-04-14 | vs OAK | 13 | W 8-6 | 8-5 | 2 | 18,490 | Butch Henry | Ariel Prieto | Tom Gordon | Billy Taylor | | 69 | 64 | 5 |
| 1998-04-15 | vs OAK | 14 | W 4-3 | 9-5 | 2 | 18,477 | Brian Rose | Jimmy Haynes | Dennis Eckersley | T.J. Mathews | | 73 | 67 | 6 |
| 1998-04-17 | vs CLE | 15 | W 3-2 | 10-5 | 2 | 26,924 | Pedro Martinez | Charles Nagy | Tom Gordon | Paul Assenmacher | | 76 | 69 | 7 |
| 1998-04-18 | vs CLE | 16 | L 4-7 | 10-6 | 3 | 31,735 | Tim Wakefield | Jaret Wright | Tom Martin | Dennis Eckersley | Michael Jackson | 80 | 76 | 4 |
| 1998-04-19 | vs CLE | 17 | W 2-0 | 11-6 | 2 | 31,846 | Bret Saberhagen | Dave Burba | Bret Saberhagen | Dave Burba | Tom Gordon | 82 | 76 | 6 |
| 1998-04-20 | vs CLE | 18 | W 6-5 | 12-6 | 1 | 33,001 | Butch Henry | Bartolo Colon | Tom Gordon | Eric Plunk | | 88 | 81 | 7 |
| 1998-04-21 | @ DET | 19 | W 11-4 | 13-6 | 2 | 10,022 | Brian Rose | Tim Worrell | Brian Rose | Tim Worrell | | 99 | 85 | 14 |
| 1998-04-22 | @ DET | 20 | W 8-5 | 14-6 | 2 | 10,102 | Pedro Martinez | Justin Thompson | Jim Corsi | Todd Jones | Tom Gordon | 107 | 90 | 17 |
| 1998-04-24 | @ CLE | 21 | W 7-5 | 15-6 | 2 | 40,570 | Tim Wakefield | Dave Burba | Tim Wakefield | Dave Burba | Tom Gordon | 114 | 95 | 19 |
| 1998-04-25 | @ CLE | 22 | W 3-2 | 16-6 | 2 | 40,571 | Bret Saberhagen | Bartolo Colon | Bret Saberhagen | Bartolo Colon | Tom Gordon | 117 | 97 | 20 |
| 1998-04-27 | vs DET | 23 | W 6-5 | 17-6 | 2 | 18,456 | Brian Rose | Justin Thompson | Dennis Eckersley | Sean Runyan | Tom Gordon | 123 | 102 | 21 |
| 1998-04-28 | vs DET | 24 | L 5-7 | 17-7 | 2 | 20,936 | Pedro Martinez | Frank Castillo | Bryce Florie | Brian Shouse | Todd Jones | 128 | 109 | 19 |
| 1998-04-29 | vs ANA | 25 | W 8-4 | 18-7 | 2 | 21,557 | Tim Wakefield | Allen Watson | Tim Wakefield | Allen Watson | Tom Gordon | 136 | 113 | 23 |
| 1998-04-30 | vs ANA | 26 | L 2-7 | 18-8 | 2 | 21,526 | Robinson Checo | Ken Hill | Ken Hill | Robinson Checo | | 138 | 120 | 18 |
| 1998-05-01 | vs TEX | 27 | W 5-3 | 19-8 | 2 | 24,169 | Bret Saberhagen | Aaron Sele | John Wasdin | Aaron Sele | Tom Gordon | 143 | 123 | 20 |
| 1998-05-02 | vs TEX | 28 | L 6-7 | 19-9 | 2 | 25,827 | Brian Rose | Rick Helling | Rick Helling | Brian Rose | John Wetteland | 149 | 130 | 19 |
| 1998-05-03 | vs TEX | 29 | W 2-1 | 20-9 | 2 | 28,075 | Pedro Martinez | Darren Oliver | Pedro Martinez | Darren Oliver | Tom Gordon | 151 | 131 | 20 |
| 1998-05-05 | vs MIN | 30 | W 4-2 | 21-9 | 2 | 20,882 | Tim Wakefield | Bob Tewksbury | Tim Wakefield | Bob Tewksbury | Tom Gordon | 155 | 133 | 22 |
| 1998-05-06 | vs MIN | 31 | L 7-8 | 21-10 | 2 | 20,954 | Robinson Checo | LaTroy Hawkins | LaTroy Hawkins | Robinson Checo | | 162 | 141 | 21 |
| 1998-05-07 | @ KCA | 32 | L 3-5 | 21-11 | 2 | 14,703 | Brian Rose | Pat Rapp | Pat Rapp | Brian Rose | Jeff Montgomery | 165 | 146 | 19 |
| 1998-05-08 | @ KCA | 33 | W 14-3 | 22-11 | 2 | 24,439 | Bret Saberhagen | Chris Haney | Bret Saberhagen | Chris Haney | Rich Garces | 179 | 149 | 30 |
| 1998-05-09 | @ KCA | 34 | W 3-1 | 23-11 | 2 | 18,035 | Pedro Martinez | Tim Belcher | Pedro Martinez | Tim Belcher | Tom Gordon | 182 | 150 | 32 |
| 1998-05-10 | @ KCA | 35 | W 3-1 | 24-11 | 2 | 14,793 | Tim Wakefield | Jose Rosado | Tim Wakefield | Jose Rosado | Tom Gordon | 185 | 151 | 34 |
| 1998-05-11 | @ TEX | 36 | L 2-8 | 24-12 | 2 | 40,275 | John Wasdin | Bobby Witt | Bobby Witt | John Wasdin | | 187 | 159 | 28 |
| 1998-05-12 | @ TEX | 37 | L 3-6 | 24-13 | 2 | 39,614 | Brian Rose | Aaron Sele | Aaron Sele | Brian Rose | John Wetteland | 190 | 165 | 25 |
| 1998-05-13 | @ MIN | 38 | L 4-7 | 24-14 | 2 | 9,076 | Bret Saberhagen | Brad Radke | Brad Radke | Bret Saberhagen | Rick Aguilera | 194 | 172 | 22 |
| 1998-05-14 | @ MIN | 39 | L 1-2 | 24-15 | 2 | 12,121 | Pedro Martinez | Mike Morgan | Mike Trombley | John Wasdin | | 195 | 174 | 21 |
| 1998-05-15 | vs KCA | 40 | W 5-2 | 25-15 | 2 | 31,466 | Tim Wakefield | Jose Rosado | Tim Wakefield | Jose Rosado | Dennis Eckersley | 200 | 176 | 24 |
| 1998-05-16 | vs KCA | 41 | W 5-0 | 26-15 | 2 | 31,700 | Steve Avery | Jamie Walker | Steve Avery | Jamie Walker | Tom Gordon | 205 | 176 | 29 |
| 1998-05-17 | vs KCA | 42 | W 5-3 | 27-15 | 2 | 29,736 | Derek Lowe | Glendon Rusch | Ron Mahay | Glendon Rusch | Tom Gordon | 210 | 179 | 31 |
| 1998-05-19 | vs CHA | 43 | L 5-9 | 27-16 | 2 | 27,121 | Bret Saberhagen | Jason Bere | Jason Bere | Bret Saberhagen | | 215 | 188 | 27 |
| 1998-05-20 | vs CHA | 44 | W 6-2 | 28-16 | 2 | 26,953 | Pedro Martinez | Jaime Navarro | Pedro Martinez | Jaime Navarro | Tom Gordon | 221 | 190 | 31 |
| 1998-05-22 | vs NYA | 45 | W 5-4 | 29-16 | 2 | 33,605 | Tim Wakefield | Ramiro Mendoza | Tim Wakefield | Jeff Nelson | Tom Gordon | 226 | 194 | 32 |
| 1998-05-23 | vs NYA | 46 | L 3-12 | 29-17 | 2 | 33,120 | Derek Lowe | David Wells | David Wells | Derek Lowe | | 229 | 206 | 23 |
| 1998-05-24 | vs NYA | 47 | L 4-14 | 29-18 | 2 | 33,042 | Bret Saberhagen | David Cone | David Cone | Bret Saberhagen | | 233 | 220 | 13 |
| 1998-05-25 | vs TOR | 48 | L 5-7 | 29-19 | 2 | 32,342 | Pedro Martinez | Pat Hentgen | Pat Hentgen | Pedro Martinez | Randy Myers | 238 | 227 | 11 |
| 1998-05-26 | vs TOR | 49 | L 2-5 | 29-20 | 2 | 27,668 | Steve Avery | Juan Guzman | Juan Guzman | Steve Avery | Randy Myers | 240 | 232 | 8 |
| 1998-05-28 | @ NYA | 50 | L 3-8 | 29-21 | 2 | 42,182 | Tim Wakefield | David Wells | David Wells | Tim Wakefield | Mike Stanton | 243 | 240 | 3 |
| 1998-05-29 | @ NYA | 51 | L 2-6 | 29-22 | 2 | 47,160 | Derek Lowe | David Cone | David Cone | Derek Lowe | | 245 | 246 | -1 |
| 1998-05-30 | @ NYA | 52 | W 3-2 | 30-22 | 2 | 55,191 | Bret Saberhagen | Hideki Irabu | Bret Saberhagen | Hideki Irabu | Tom Gordon | 248 | 248 | 0 |
| 1998-05-31 | @ NYA | 53 | W 13-7 | 31-22 | 2 | 55,711 | Pedro Martinez | Andy Pettitte | Pedro Martinez | Andy Pettitte | | 261 | 255 | 6 |
| 1998-06-01 | @ TOR | 54 | W 9-5 | 32-22 | 2 | 27,372 | Tim Wakefield | Juan Guzman | Jim Corsi | Randy Myers | | 270 | 260 | 10 |
| 1998-06-02 | @ TOR | 55 | W 11-3 | 33-22 | 2 | 26,177 | Steve Avery | Chris Carpenter | Steve Avery | Chris Carpenter | | 281 | 263 | 18 |
| 1998-06-03 | vs BAL | 56 | L 0-3 | 33-23 | 2 | 31,355 | Derek Lowe | Doug Johns | Doug Johns | Derek Lowe | Arthur Rhodes | 281 | 266 | 15 |
| 1998-06-04 | vs BAL | 57 | W 9-1 | 34-23 | 2 | 33,104 | Bret Saberhagen | Sidney Ponson | Bret Saberhagen | Sidney Ponson | | 290 | 267 | 23 |
| 1998-06-05 | vs NYN | 58 | L 2-9 | 34-24 | 2 | 32,214 | Pedro Martinez | Al Leiter | Al Leiter | Pedro Martinez | | 292 | 276 | 16 |
| 1998-06-06 | vs NYN | 59 | L 0-1 | 34-25 | 2 | 32,545 | Tim Wakefield | Bobby Jones | Bobby Jones | Tim Wakefield | John Franco | 292 | 277 | 15 |
| 1998-06-07 | vs NYN | 60 | W 5-0 | 35-25 | 2 | 30,630 | Steve Avery | Masato Yoshii | Steve Avery | Masato Yoshii | | 297 | 277 | 20 |
| 1998-06-08 | @ ATL | 61 | L 6-7 | 35-26 | 2 | 44,018 | Derek Lowe | Tom Glavine | Alan Embree | John Wasdin | | 303 | 284 | 19 |
| 1998-06-09 | @ ATL | 62 | W 9-3 | 36-26 | 2 | 43,121 | Bret Saberhagen | Dennis Martinez | Bret Saberhagen | Dennis Martinez | | 312 | 287 | 25 |
| 1998-06-10 | @ ATL | 63 | W 10-6 | 37-26 | 2 | 41,345 | Pedro Martinez | Denny Neagle | Pedro Martinez | Denny Neagle | | 322 | 293 | 29 |
| 1998-06-12 | vs TBA | 64 | W 5-1 | 38-26 | 2 | 31,994 | Tim Wakefield | Rolando Arrojo | Tim Wakefield | Rolando Arrojo | | 327 | 294 | 33 |
| 1998-06-14 | vs TBA | 65 | W 3-2 | 39-26 | 2 | 27,768 | Steve Avery | Tony Saunders | Tom Gordon | Albie Lopez | | 330 | 296 | 34 |
| 1998-06-15 | @ CHA | 66 | L 2-3 | 39-27 | 2 | 16,130 | Bret Saberhagen | Jim Parque | Jim Parque | Bret Saberhagen | Matt Karchner | 332 | 299 | 33 |
| 1998-06-16 | @ CHA | 67 | W 6-1 | 40-27 | 2 | 13,483 | Pedro Martinez | Jason Bere | Pedro Martinez | Jason Bere | | 338 | 300 | 38 |
| 1998-06-17 | @ CHA | 68 | W 12-5 | 41-27 | 2 | 13,563 | Tim Wakefield | Scott Eyre | Tim Wakefield | Scott Eyre | Tom Gordon | 350 | 305 | 45 |
| 1998-06-18 | @ TBA | 69 | W 7-5 | 42-27 | 2 | 30,177 | Derek Lowe | Dennis Springer | John Wasdin | Esteban Yan | Tom Gordon | 357 | 310 | 47 |
| 1998-06-19 | @ TBA | 70 | W 4-1 | 43-27 | 2 | 32,375 | Steve Avery | Tony Saunders | Steve Avery | Tony Saunders | Tom Gordon | 361 | 311 | 50 |
| 1998-06-20 | @ TBA | 71 | L 5-8 | 43-28 | 2 | 41,169 | Bret Saberhagen | Julio Santana | Julio Santana | Bret Saberhagen | Roberto Hernandez | 366 | 319 | 47 |
| 1998-06-21 | @ TBA | 72 | W 3-1 | 44-28 | 2 | 40,348 | Pedro Martinez | Jason Johnson | Pedro Martinez | Jason Johnson | Tom Gordon | 369 | 320 | 49 |
| 1998-06-22 | vs PHI | 73 | L 8-9 | 44-29 | 2 | 33,592 | Tim Wakefield | Curt Schilling | Wayne Gomes | Tom Gordon | Mark Leiter | 377 | 329 | 48 |
| 1998-06-23 | vs PHI | 74 | L 2-3 | 44-30 | 2 | 33,212 | Derek Lowe | Mark Portugal | Mark Portugal | Derek Lowe | | 379 | 332 | 47 |
| 1998-06-24 | @ PHI | 75 | L 8-11 | 44-31 | 2 | 28,079 | Steve Avery | Carlton Loewer | Carlton Loewer | Steve Avery | Mark Leiter | 387 | 343 | 44 |
| 1998-06-25 | @ PHI | 76 | W 7-5 | 45-31 | 2 | 28,263 | Bret Saberhagen | Matt Beech | Bret Saberhagen | Matt Beech | Ron Mahay | 394 | 348 | 46 |
| 1998-06-26 | @ FLO | 77 | W 6-1 | 46-31 | 2 | 23,792 | Pedro Martinez | Joe Fontenot | Pedro Martinez | Joe Fontenot | | 400 | 349 | 51 |
| 1998-06-27 | @ FLO | 78 | W 9-4 | 47-31 | 2 | 31,212 | Tim Wakefield | Jesus Sanchez | Tim Wakefield | Jesus Sanchez | | 409 | 353 | 56 |
| 1998-06-28 | @ FLO | 79 | L 1-5 | 47-32 | 2 | 28,418 | Derek Lowe | Ryan Dempster | Ryan Dempster | Derek Lowe | Antonio Alfonseca | 410 | 358 | 52 |
| 1998-06-30 | vs MON | 80 | W 7-4 | 48-32 | 2 | 27,704 | Steve Avery | Carlos Perez | Steve Avery | Carlos Perez | Tom Gordon | 417 | 362 | 55 |
| 1998-07-01 | vs MON | 81 | W 6-1 | 49-32 | 2 | 24,923 | Bret Saberhagen | Dustin Hermanson | Bret Saberhagen | Dustin Hermanson | | 423 | 363 | 60 |
| 1998-07-02 | vs MON | 82 | W 15-0 | 50-32 | 2 | 32,637 | Pedro Martinez | Carl Pavano | Pedro Martinez | Carl Pavano | | 438 | 363 | 75 |
| 1998-07-03 | vs CHA | 83 | W 15-2 | 51-32 | 2 | 32,467 | Tim Wakefield | Mike Sirotka | Tim Wakefield | Mike Sirotka | | 453 | 365 | 88 |
| 1998-07-04 | vs CHA | 84 | L 0-3 | 51-33 | 2 | 29,600 | Jin Ho Cho | John Snyder | John Snyder | Jin Ho Cho | Bill Simas | 453 | 368 | 85 |
| 1998-07-05 | vs CHA | 85 | W 15-14 | 52-33 | 2 | 32,970 | Steve Avery | Jaime Navarro | Carlos Reyes | Bob Howry | Tom Gordon | 468 | 382 | 86 |
| 1998-07-09 | @ BAL | 86 | L 2-3 | 52-34 | 2 | 48,014 | Bret Saberhagen | Mike Mussina | Jesse Orosco | Jim Corsi | Armando Benitez | 470 | 385 | 85 |
| 1998-07-10 | @ BAL | 87 | L 2-3 | 52-35 | 2 | 48,043 | Pedro Martinez | Sidney Ponson | Jesse Orosco | Pedro Martinez | Armando Benitez | 472 | 388 | 84 |
| 1998-07-11 | @ BAL | 88 | L 1-2 | 52-36 | 2 | 48,244 | Tim Wakefield | Scott Erickson | Scott Erickson | Tim Wakefield | Jesse Orosco | 473 | 390 | 83 |
| 1998-07-12 | @ BAL | 89 | L 7-11 | 52-37 | 2 | 48,193 | Jin Ho Cho | Doug Drabek | Doug Johns | Jin Ho Cho | Alan Mills | 480 | 401 | 79 |
| 1998-07-13 | @ TBA | 90 | W 2-0 | 53-37 | 2 | 29,186 | Steve Avery | Julio Santana | Steve Avery | Julio Santana | Tom Gordon | 482 | 401 | 81 |
| 1998-07-14 | @ TBA | 91 | L 4-5 | 53-38 | 2 | 27,310 | Bret Saberhagen | Bryan Rekar | Albie Lopez | Ron Mahay | | 486 | 406 | 80 |
| 1998-07-15 | vs CLE | 92 | W 1-0 | 54-38 | 2 | 33,501 | Pedro Martinez | Bartolo Colon | Pedro Martinez | Bartolo Colon | | 487 | 406 | 81 |
| 1998-07-16 | vs CLE | 93 | W 15-5 | 55-38 | 2 | 33,568 | Tim Wakefield | Dwight Gooden | Tim Wakefield | Dwight Gooden | Derek Lowe | 502 | 411 | 91 |
| 1998-07-17 | @ DET | 94 | L 4-6 | 55-39 | 2 | 26,255 | Jin Ho Cho | Brian Powell | Brian Powell | Jin Ho Cho | Todd Jones | 506 | 417 | 89 |
| 1998-07-18 | @ DET | 95 | W 9-4 | 56-39 | 2 | 22,983 | Steve Avery | Frank Castillo | Steve Avery | Frank Castillo | Derek Lowe | 515 | 421 | 94 |
| 1998-07-19 | @ DET | 96 | L 1-3 | 56-40 | 2 | 21,018 | Bret Saberhagen | Justin Thompson | Justin Thompson | Tom Gordon | | 516 | 424 | 92 |
| 1998-07-21 | @ CLE | 97 | W 10-7 | 57-41 | 2 | 42,874 | Pedro Martinez | Dwight Gooden | Pedro Martinez | Dwight Gooden | Tom Gordon | 526 | 431 | 95 |
| 1998-07-21 | @ CLE | 98 | L 2-4 | 57-41 | 2 | 43,227 | Tim Wakefield | Chad Ogea | Chad Ogea | Tim Wakefield | Michael Jackson | 528 | 435 | 93 |
| 1998-07-22 | @ CLE | 99 | L 3-4 | 57-42 | 2 | 43,073 | John Wasdin | Charles Nagy | Charles Nagy | Rich Garces | Michael Jackson | 531 | 439 | 92 |
| 1998-07-23 | vs TOR | 100 | W 8-7 | 58-42 | 2 | 33,011 | Jin Ho Cho | Chris Carpenter | Tom Gordon | Randy Myers | | 539 | 446 | 93 |
| 1998-07-24 | vs TOR | 101 | L 6-10 | 58-43 | 2 | 33,159 | Steve Avery | Juan Guzman | Juan Guzman | Steve Avery | Paul Quantrill | 545 | 456 | 89 |
| 1998-07-25 | vs TOR | 102 | W 5-3 | 59-43 | 2 | 33,099 | Bret Saberhagen | Woody Williams | Derek Lowe | Woody Williams | Tom Gordon | 550 | 459 | 91 |
| 1998-07-26 | vs TOR | 103 | W 6-3 | 60-43 | 2 | 33,059 | Pedro Martinez | Pat Hentgen | Pedro Martinez | Pat Hentgen | | 556 | 462 | 94 |
| 1998-07-28 | @ OAK | 104 | W 8-4 | 61-43 | 2 | 11,208 | Tim Wakefield | Jimmy Haynes | Tim Wakefield | Jimmy Haynes | Tom Gordon | 564 | 466 | 98 |
| 1998-07-29 | @ OAK | 105 | W 10-2 | 62-43 | 2 | 11,632 | John Wasdin | Mike Oquist | John Wasdin | Mike Oquist | Derek Lowe | 574 | 468 | 106 |
| 1998-07-30 | @ OAK | 106 | L 5-6 | 62-44 | 2 | 17,535 | Steve Avery | Kenny Rogers | Kenny Rogers | Steve Avery | Billy Taylor | 579 | 474 | 105 |
| 1998-07-31 | @ ANA | 107 | W 7-2 | 63-44 | 2 | 43,390 | Bret Saberhagen | Omar Olivares | Bret Saberhagen | Omar Olivares | Tom Gordon | 586 | 476 | 110 |
| 1998-08-01 | @ ANA | 108 | W 11-3 | 64-44 | 2 | 29,893 | Pedro Martinez | Allen Watson | Pedro Martinez | Allen Watson | Derek Lowe | 597 | 479 | 118 |
| 1998-08-02 | @ ANA | 109 | W 8-7 | 65-44 | 2 | 35,763 | Tim Wakefield | Jason Dickson | Tim Wakefield | Jason Dickson | Tom Gordon | 605 | 486 | 119 |
| 1998-08-03 | @ SEA | 110 | L 1-3 | 65-45 | 2 | 27,887 | John Wasdin | Ken Cloude | Ken Cloude | John Wasdin | Mike Timlin | 606 | 489 | 117 |
| 1998-08-04 | @ SEA | 111 | W 2-1 | 66-45 | 2 | 29,621 | Steve Avery | Bill Swift | Steve Avery | Greg McCarthy | Tom Gordon | 608 | 490 | 118 |
| 1998-08-06 | @ TEX | 112 | L 4-7 | 66-46 | 2 | 32,132 | Bret Saberhagen | John Burkett | John Burkett | Bret Saberhagen | John Wetteland | 612 | 497 | 115 |
| 1998-08-07 | @ TEX | 113 | L 3-4 | 66-47 | 2 | 34,906 | Pedro Martinez | Rick Helling | Rick Helling | Pedro Martinez | John Wetteland | 615 | 501 | 114 |
| 1998-08-08 | @ TEX | 114 | W 11-1 | 67-47 | 2 | 44,242 | Tim Wakefield | Aaron Sele | Tim Wakefield | Aaron Sele | | 626 | 502 | 124 |
| 1998-08-09 | @ TEX | 115 | W 14-8 | 68-47 | 2 | 31,127 | John Wasdin | Todd Stottlemyre | Jim Corsi | Todd Stottlemyre | | 640 | 510 | 130 |
| 1998-08-11 | vs KCA | 116 | W 7-4 | 69-47 | 2 | 33,290 | Steve Avery | Tim Belcher | Tom Gordon | Jeff Montgomery | | 647 | 514 | 133 |
| 1998-08-12 | vs KCA | 117 | L 4-8 | 69-48 | 2 | 32,488 | Bret Saberhagen | Jose Rosado | Scott Service | Greg Swindell | | 651 | 522 | 129 |
| 1998-08-13 | vs MIN | 118 | W 8-7 | 70-48 | 2 | 32,801 | Pedro Martinez | Brad Radke | Dennis Eckersley | Travis Miller | Tom Gordon | 659 | 529 | 130 |
| 1998-08-14 | vs MIN | 119 | W 13-12 | 71-48 | 2 | 32,888 | Tim Wakefield | Dan Serafini | Derek Lowe | Travis Baptist | Tom Gordon | 672 | 541 | 131 |
| 1998-08-15 | vs MIN | 120 | L 2-3 | 71-49 | 2 | 32,412 | John Wasdin | Frankie Rodriguez | Frankie Rodriguez | Pete Schourek | Rick Aguilera | 674 | 544 | 130 |
| 1998-08-16 | vs MIN | 121 | L 3-6 | 71-50 | 2 | 30,893 | Steve Avery | Eric Milton | Eric Milton | Steve Avery | Rick Aguilera | 677 | 550 | 127 |
| 1998-08-18 | vs TEX | 122 | W 4-1 | 73-50 | 2 | 33,201 | Pedro Martinez | John Burkett | Pedro Martinez | John Burkett | Tom Gordon | 681 | 551 | 130 |
| 1998-08-18 | vs TEX | 123 | W 5-4 | 73-50 | 2 | 26,677 | Bret Saberhagen | Rick Helling | Derek Lowe | Danny Patterson | Tom Gordon | 686 | 555 | 131 |
| 1998-08-19 | @ KCA | 124 | W 11-1 | 74-50 | 2 | 14,017 | Tim Wakefield | Brian Barber | Tim Wakefield | Brian Barber | | 697 | 556 | 141 |
| 1998-08-20 | @ KCA | 125 | L 2-8 | 74-51 | 2 | 14,278 | Pete Schourek | Hipolito Pichardo | Hipolito Pichardo | Pete Schourek | | 699 | 564 | 135 |
| 1998-08-21 | @ MIN | 126 | W 9-2 | 75-51 | 2 | 16,786 | Steve Avery | Eric Milton | Steve Avery | Eric Milton | | 708 | 566 | 142 |
| 1998-08-22 | @ MIN | 127 | L 3-4 | 75-52 | 2 | 18,415 | John Wasdin | LaTroy Hawkins | Mike Trombley | Greg Swindell | | 711 | 570 | 141 |
| 1998-08-23 | @ MIN | 128 | W 5-1 | 76-52 | 2 | 12,686 | Pedro Martinez | Brad Radke | Pedro Martinez | Brad Radke | | 716 | 571 | 145 |
| 1998-08-25 | vs OAK | 129 | W 3-2 | 77-52 | 2 | 28,366 | Tim Wakefield | Kenny Rogers | Greg Swindell | Kenny Rogers | Tom Gordon | 719 | 573 | 146 |
| 1998-08-26 | vs OAK | 130 | W 7-4 | 78-52 | 2 | 26,379 | Bret Saberhagen | Blake Stein | John Wasdin | Tim Worrell | Tom Gordon | 726 | 577 | 149 |
| 1998-08-27 | vs OAK | 131 | L 3-6 | 78-53 | 2 | 31,239 | Pete Schourek | Tom Candiotti | Tom Candiotti | Pete Schourek | Billy Taylor | 729 | 583 | 146 |
| 1998-08-28 | vs ANA | 132 | L 6-7 | 78-54 | 2 | 32,470 | Steve Avery | Ken Hill | Ken Hill | Steve Avery | | 735 | 590 | 145 |
| 1998-08-29 | vs ANA | 133 | W 6-1 | 79-54 | 2 | 32,519 | Pedro Martinez | Jack McDowell | Pedro Martinez | Jack McDowell | | 741 | 591 | 150 |
| 1998-08-30 | vs ANA | 134 | L 6-8 | 79-55 | 2 | 31,476 | Tim Wakefield | Jeff Juden | Shigetoshi Hasegawa | Tim Wakefield | Troy Percival | 747 | 599 | 148 |
| 1998-08-31 | vs SEA | 135 | W 5-1 | 80-55 | 2 | 28,553 | Bret Saberhagen | Jeff Fassero | Bret Saberhagen | Jeff Fassero | | 752 | 600 | 152 |
| 1998-09-01 | vs SEA | 136 | L 3-7 | 80-56 | 2 | 28,150 | Pete Schourek | Jamie Moyer | Jamie Moyer | Derek Lowe | | 755 | 607 | 148 |
| 1998-09-02 | vs SEA | 137 | W 7-3 | 81-56 | 2 | 25,813 | Steve Avery | Mac Suzuki | Tom Gordon | Bobby Ayala | | 762 | 610 | 152 |
| 1998-09-03 | @ TOR | 138 | L 3-4 | 81-57 | 2 | 27,226 | Pedro Martinez | Woody Williams | Robert Person | Dario Veras | | 765 | 614 | 151 |
| 1998-09-04 | @ TOR | 139 | L 1-12 | 81-58 | 2 | 29,166 | Tim Wakefield | Pat Hentgen | Pat Hentgen | Tim Wakefield | Dave Stieb | 766 | 626 | 140 |
| 1998-09-05 | @ TOR | 140 | L 3-4 | 81-59 | 2 | 37,158 | Bret Saberhagen | Roger Clemens | Roger Clemens | Bret Saberhagen | Paul Quantrill | 769 | 630 | 139 |
| 1998-09-06 | @ TOR | 141 | L 7-8 | 81-60 | 2 | 38,374 | Pete Schourek | Chris Carpenter | Paul Quantrill | Derek Lowe | Robert Person | 776 | 638 | 138 |
| 1998-09-07 | vs NYA | 142 | W 4-3 | 82-60 | 2 | 32,106 | Steve Avery | David Wells | Greg Swindell | David Wells | Tom Gordon | 780 | 641 | 139 |
| 1998-09-08 | vs NYA | 143 | L 2-3 | 82-61 | 2 | 33,409 | Pedro Martinez | David Cone | David Cone | Pedro Martinez | Mariano Rivera | 782 | 644 | 138 |
| 1998-09-09 | vs NYA | 144 | L 5-7 | 82-62 | 2 | 32,942 | Tim Wakefield | Orlando Hernandez | Ramiro Mendoza | Tim Wakefield | Mariano Rivera | 787 | 651 | 136 |
| 1998-09-11 | vs DET | 145 | W 6-2 | 83-62 | 2 | 29,131 | Bret Saberhagen | Brian Powell | Bret Saberhagen | Brian Powell | Tom Gordon | 793 | 653 | 140 |
| 1998-09-12 | vs DET | 146 | L 2-3 | 83-63 | 2 | 31,220 | Pete Schourek | Bryce Florie | Matt Anderson | Tom Gordon | Todd Jones | 795 | 656 | 139 |
| 1998-09-13 | vs DET | 147 | L 1-4 | 83-64 | 2 | 31,255 | Steve Avery | Brian Moehler | Brian Moehler | Greg Swindell | Todd Jones | 796 | 660 | 136 |
| 1998-09-14 | @ NYA | 148 | L 0-3 | 83-65 | 2 | 42,735 | Pedro Martinez | Orlando Hernandez | Orlando Hernandez | Pedro Martinez | | 796 | 663 | 133 |
| 1998-09-15 | @ NYA | 149 | W 9-4 | 84-65 | 2 | 43,218 | Tim Wakefield | Mike Jerzembeck | Tim Wakefield | Mike Jerzembeck | | 805 | 667 | 138 |
| 1998-09-16 | @ BAL | 150 | W 4-3 | 85-65 | 2 | 42,676 | Bret Saberhagen | Scott Erickson | Bret Saberhagen | Scott Erickson | Tom Gordon | 809 | 670 | 139 |
| 1998-09-17 | @ BAL | 151 | W 3-2 | 86-65 | 2 | 44,565 | Pete Schourek | Mike Mussina | Dennis Eckersley | Armando Benitez | Tom Gordon | 812 | 672 | 140 |
| 1998-09-18 | @ CHA | 152 | L 9-11 | 86-66 | 2 | 17,767 | Steve Avery | Jim Parque | Jim Parque | Steve Avery | Bill Simas | 821 | 683 | 138 |
| 1998-09-19 | @ CHA | 153 | L 2-5 | 86-67 | 2 | 21,924 | Pedro Martinez | John Snyder | John Snyder | Pedro Martinez | | 823 | 688 | 135 |
| 1998-09-20 | @ CHA | 154 | L 4-6 | 86-68 | 2 | 24,165 | Tim Wakefield | Mike Sirotka | Mike Sirotka | Jim Corsi | Bryan Ward | 827 | 694 | 133 |
| 1998-09-21 | vs TBA | 155 | W 4-3 | 87-69 | 2 | 0 | Bret Saberhagen | Tony Saunders | Bret Saberhagen | Tony Saunders | Tom Gordon | 831 | 697 | 134 |
| 1998-09-21 | vs TBA | 156 | L 4-8 | 87-69 | 2 | 23,379 | John Wasdin | Terrell Wade | Terrell Wade | Carlos Reyes | | 835 | 705 | 130 |
| 1998-09-22 | vs TBA | 157 | W 11-2 | 88-69 | 2 | 20,399 | Pete Schourek | Julio Santana | Pete Schourek | Julio Santana | | 846 | 707 | 139 |
| 1998-09-23 | vs TBA | 158 | W 5-4 | 89-69 | 2 | 23,240 | Steve Avery | Bryan Rekar | Steve Avery | Bryan Rekar | Tom Gordon | 851 | 711 | 140 |
| 1998-09-24 | vs BAL | 159 | W 9-6 | 90-69 | 2 | 30,997 | Pedro Martinez | Sidney Ponson | Pedro Martinez | Sidney Ponson | Tom Gordon | 860 | 717 | 143 |
| 1998-09-25 | vs BAL | 160 | W 8-3 | 91-69 | 2 | 32,644 | Tim Wakefield | Chris Fussell | Tim Wakefield | Chris Fussell | | 868 | 720 | 148 |
| 1998-09-26 | vs BAL | 161 | L 2-5 | 91-70 | 2 | 29,226 | Bret Saberhagen | Scott Erickson | Scott Erickson | Bret Saberhagen | Armando Benitez | 870 | 725 | 145 |
| 1998-09-27 | vs BAL | 162 | W 6-4 | 92-70 | 2 | 32,158 | Pete Schourek | Mike Mussina | Carlos Valdez | Mike Mussina | Tom Gordon | 876 | 729 | 147 |