| Starter | Tm | Tier | Game |
|---|---|---|---|
| Orel Hershiser | LAN | 6.49 | 198909030_WAS_LAN |
| Bert Blyleven | ANA | 4.05 | 198909030_ANA_NYA |
| Chris Bosio | MIL | 4.03 | 198909010_OAK_MIL |
| Scott Garrelts | SFN | 3.29 | 198909010_NYN_SFN |
| Mark Gubicza | KCA | 3.19 | 198909030_KCA_TEX |
| Starter | Tm | Tier | Game |
|---|---|---|---|
| Melido Perez | CHA | -4.25 | 198909030_BAL_CHA |
| Andy Hawkins | NYA | -2.68 | 198909030_ANA_NYA |
| Jack Morris | DET | -2.05 | 198909030_CLE_DET |
| Bob Forsch | HOU | -2 | 198909020_HOU_SLN |
| Mike Dunne | SEA | -1.73 | 198909020_SEA_BOS |
Based on accumulated WAA for this season up to 1989-09-03.
| Rank | WAA | Name | IP | Tm |
|---|---|---|---|---|
| +004+ | 6.54 | Orel Hershiser | 219 | LAN |
| +007+ | 6.2 | Bret Saberhagen | 207.7 | KCA |
| +009+ | 5.71 | Mike Moore | 201.3 | OAK |
| +010+ | 5.54 | Chris Bosio | 217.7 | MIL |
| +014+ | 5.25 | Scott Garrelts | 155.7 | SFN |
| +017+ | 5.07 | Chuck Finley | 176.3 | ANA |
| +019+ | 5.01 | Mark Gubicza | 237.7 | KCA |
| +020+ | 4.75 | Bert Blyleven | 204 | ANA |
| +022+ | 4.71 | John Smiley | 187.7 | PIT |
| +023+ | 4.7 | Ed Whitson | 198 | SDN |
| +025+ | 4.51 | Rick Reuschel | 176.3 | SFN |
| +027+ | 4.36 | Greg Maddux | 205 | CHN |
| +031+ | 4.23 | Bryn Smith | 186 | WAS |
| +032+ | 4.21 | Mark Langston | 218.3 | TOT |
| +035+ | 4.1 | Joe Magrane | 205.3 | SLN |
| +036+ | 4.04 | Doug Drabek | 212 | PIT |
| +041+ | 3.72 | Sid Fernandez | 174 | NYN |
| +043+ | 3.69 | Bob Welch | 178 | OAK |
| +046+ | 3.62 | Bruce Hurst | 207.3 | SDN |
| +047+ | 3.59 | John Cerutti | 180 | TOR |
| +048+ | 3.49 | Mike Morgan | 145.7 | LAN |
| +050+ | 3.46 | Dennis Martinez | 201.7 | WAS |
| +053+ | 3.44 | John Smoltz | 203.7 | ATL |
| +054+ | 3.39 | Tom Browning | 222.7 | CIN |
| +056+ | 3.32 | Kirk McCaskill | 170.7 | ANA |
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