Bert Blyleven vs Jerry Koosman: Career Stats Comparison
Bert Blyleven has the better career line of the two, leading 8 of the 8 scored categories on this page (8 further counting totals are shown but not scored). Bert Blyleven played 1970–1992 as a pitcher; Jerry Koosman played 1967–1985 as a pitcher.
- ERA (Earned Run Average):
- Earned runs allowed per nine innings pitched: (ER × 9) ÷ IP. The primary measure of pitching effectiveness.
- W (Wins):
- Games credited to a pitcher whose team took a lead it never surrendered while he was the pitcher of record.
- SO (Strikeouts):
- For a batter, times retired on a third strike; for a pitcher, batters retired on a third strike.
- WHIP (Walks and Hits per Inning Pitched):
- Baserunners allowed per inning: (BB + H) ÷ IP. Under 1.00 is elite.
Data updated
Bert Blyleven (1970–1992) and Jerry Koosman (1967–1985) — they debuted in the 1970s and the 1960s respectively and share 16 seasons. Bert Blyleven finished with 287 wins and 3,701 strikeouts; Jerry Koosman finished with 222 wins and 2,556 strikeouts. The table below sets out their careers line by line.
Quick answer
- Who leads the career comparison? Bert Blyleven, in 8 of the 8 scored categories.
- Who had the better ERA? Bert Blyleven, with 3.31 to Jerry Koosman's 3.36.
- Who won more games? Bert Blyleven, with 287 to Jerry Koosman's 222.
- Who recorded more strikeouts? Bert Blyleven, with 3,701 to Jerry Koosman's 2,556.
- Who had the better WHIP? Bert Blyleven, with 1.20 to Jerry Koosman's 1.26.
- How many innings did each pitch? Bert Blyleven 4,970.0, Jerry Koosman 3,839.1.
- Who threw more shutouts? Bert Blyleven, with 60 to Jerry Koosman's 33.
Bert Blyleven
Jerry Koosman
Career Stats Side-by-Side
Every cell below is a career total or career rate. Cells highlighted in green mark the player who leads that line. Lower ERA, WHIP and BB/9 lead; higher K/9 leads. 8 of the 16 lines below are scored; the other 8 are shown but not scored. Games, starts and innings measure playing time, and losses, walks and hits allowed track how long someone pitched, so they are left unmarked, as is any line where both players are at zero. Rate stats are not era-adjusted, so read them against the run environment each player worked in, or use the PIV card below, which is adjusted.
| Statistic | Bert Blyleven | Jerry Koosman |
|---|---|---|
| Wins | Leads: 287 | 222 |
| Losses not scored | 250 | 209 |
| Games not scored | 692 | 612 |
| Games Started not scored | 685 | 527 |
| Complete Games | Leads: 242 | 140 |
| Shutouts | Leads: 60 | 33 |
| Saves not scored | 0 | 17 |
| Strikeouts | Leads: 3,701 | 2,556 |
| Walks not scored | 1,322 | 1,198 |
| Hits Allowed not scored | 4,632 | 3,635 |
| Home Runs Allowed not scored | 430 | 290 |
| Innings Pitched not scored | 4,970.0 | 3,839.1 |
| ERA | Leads: 3.31 | 3.36 |
| WHIP | Leads: 1.20 | 1.26 |
| K/9 | Leads: 6.70 | 5.99 |
| BB/9 | Leads: 2.39 | 2.81 |
PIV Comparison
By PIV (Player Impact Value), Bert Blyleven outpaces Jerry Koosman 74,910 to 42,939 — driven by both sides of the ledger: 3,405 PIV per season to 2,260, across 22 seasons to 19. PIV adjusts each season to league baselines, so it's the cleanest way to compare careers across eras.
Peak Seasons
The best single seasons each player produced, ranked by ERA among qualified workloads (120+ innings).
Bert Blyleven — top 3 seasons by ERA (lower is better)
Jerry Koosman — top 3 seasons by ERA (lower is better)
Verdict
Bert Blyleven leads 8 of the 8 scored categories on the head-to-head card: wins, complete games, shutouts, strikeouts, and others. Jerry Koosman leads 0: no scored category. On the raw scoreboard the edge goes to Bert Blyleven. PIV agrees: Bert Blyleven grades out higher across their careers. Click through to each profile for the full season-by-season breakdown.
Related Matchups
How the Bert Blyleven and Jerry Koosman careers compare
From 1970 through 1985, Bert Blyleven and Jerry Koosman were in the majors together. The two careers are close in length, 692 games for Bert Blyleven and 612 for Jerry Koosman across 22 and 19 PIV seasons, so the totals compare on fairly even terms. Every scored category on the table goes to Bert Blyleven. The per-nine rows read 6.70 strikeouts and 2.39 walks for Bert Blyleven, 5.99 and 2.81 for Jerry Koosman. Bert Blyleven was mainly a starter (685 starts in 692 games), and Jerry Koosman was mainly a starter (527 starts in 612 games). In WHIP, Bert Blyleven's 1.20 beats Jerry Koosman's 1.26.
Bert Blyleven vs Jerry Koosman: Frequently Asked Questions
- Who was better, Bert Blyleven or Jerry Koosman?
- By the career statistics compared on this page, Bert Blyleven leads Jerry Koosman in 8 of the 8 scored categories.
- Who had the better ERA?
- Bert Blyleven, with 3.31 to Jerry Koosman's 3.36.
- Who won more games?
- Bert Blyleven, with 287 to Jerry Koosman's 222.
- Who recorded more strikeouts?
- Bert Blyleven, with 3,701 to Jerry Koosman's 2,556.
- Who had the better WHIP?
- Bert Blyleven, with 1.20 to Jerry Koosman's 1.26.