Jerry Koosman vs Tom Seaver: Career Stats Comparison
Jerry Koosman (1967–1985) and Tom Seaver (1967–1986) — both came up during the 1960s, so the matchup is a direct one. Jerry Koosman compiled 222 wins and 2,556 strikeouts; Tom Seaver put up 311 wins and 3,640 strikeouts. The numbers below run them through identical career and rate-stat lenses.
Jerry Koosman
Tom Seaver
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. For pitchers, lower ERA, WHIP, and BB/9 lead; higher K/9 leads.
| Statistic | Jerry Koosman | Tom Seaver |
|---|---|---|
| Wins | 222 | 311 |
| Losses | 209 | 205 |
| Games | 612 | 656 |
| Games Started | 527 | 647 |
| Complete Games | 140 | 231 |
| Shutouts | 33 | 61 |
| Saves | 17 | 1 |
| Strikeouts | 2,556 | 3,640 |
| Walks | 1,198 | 1,390 |
| Hits Allowed | 3,635 | 3,971 |
| Home Runs Allowed | 290 | 380 |
| Innings Pitched | 3,839 | 4,782 |
| ERA | 3.36 | 2.86 |
| WHIP | 1.26 | 1.12 |
| K/9 | 5.99 | 6.85 |
| BB/9 | 2.81 | 2.62 |
PIV Comparison
By PIV (Player Impact Value), Tom Seaver outpaces Jerry Koosman 79,192 to 42,939 — a gap driven primarily by per-season impact (3,600 vs 2,147 per year). 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).
Jerry Koosman — top 3 seasons by ERA (lower is better)
Tom Seaver — top 3 seasons by ERA (lower is better)
Verdict
On the head-to-head card, Tom Seaver leads in wins, strikeouts, ERA, and WHIP, while Jerry Koosman owns no headline categories. That doesn't settle the era debate, but on the raw scoreboard the edge goes to Tom Seaver. PIV agrees: Tom Seaver grades out higher across their careers. Click through to each profile for the full season-by-season breakdown.