| Starter | Tm | Tier | Game |
|---|---|---|---|
| Scott Garrelts | SFN | 4.51 | 198909270_SFN_LAN |
| Mike Moore | OAK | 4.33 | 198909270_TEX_OAK |
| Bruce Hurst | SDN | 3.51 | 198909270_CIN_SDN |
| Mark Langston | WAS | 3.31 | 198909290_WAS_PHI |
| Bert Blyleven | ANA | 2.91 | 198909280_KCA_ANA |
| Starter | Tm | Tier | Game |
|---|---|---|---|
| Bobby Witt | TEX | -6 | 198909290_TEX_ANA |
| Walt Terrell | NYA | -2.41 | 198909270_NYA_BOS |
| Mike Witt | ANA | -1.94 | 198909290_TEX_ANA |
| Jerry Reuss | MIL | -1.93 | 198909270_BAL_MIL |
| Jack Morris | DET | -1.88 | 198909290_DET_NYA |
Based on accumulated WAA for this season up to 1989-09-29.
| Rank | WAA | Name | IP | Tm |
|---|---|---|---|---|
| +002+ | 9.24 | Bret Saberhagen | 255 | KCA |
| +006+ | 7.19 | Orel Hershiser | 246 | LAN |
| +010+ | 6.35 | Scott Garrelts | 193.7 | SFN |
| +011+ | 6.25 | Mike Moore | 242 | OAK |
| +015+ | 5.72 | Bruce Hurst | 245.3 | SDN |
| +019+ | 5.58 | Mark Langston | 251.3 | TOT |
| +020+ | 5.44 | Bert Blyleven | 241 | ANA |
| +021+ | 5.4 | Ed Whitson | 227 | SDN |
| +023+ | 5.11 | Chuck Finley | 193.3 | ANA |
| +026+ | 4.96 | Rick Reuschel | 204.3 | SFN |
| +032+ | 4.7 | Doug Drabek | 245.3 | PIT |
| +033+ | 4.69 | Bryn Smith | 210.7 | WAS |
| +034+ | 4.67 | Chris Bosio | 235 | MIL |
| +038+ | 4.39 | Tim Belcher | 230.3 | LAN |
| +041+ | 4.21 | Joe Magrane | 234.7 | SLN |
| +042+ | 4.14 | Sid Fernandez | 211 | NYN |
| +045+ | 4.06 | Greg Maddux | 238.3 | CHN |
| +047+ | 4.05 | Mark Gubicza | 255.7 | KCA |
| +049+ | 4.04 | Kirk McCaskill | 207.7 | ANA |
| +051+ | 3.88 | Mike Morgan | 152.3 | LAN |
| +052+ | 3.85 | John Smiley | 205.3 | PIT |
| +063+ | 3.66 | Jose DeLeon | 238 | SLN |
| +068+ | 3.43 | Rick Aguilera | 144.7 | TOT |
| +072+ | 3.29 | Bob Welch | 205.3 | OAK |
| +073+ | 3.27 | Todd Burns | 96 | OAK |
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