Jerry Koosman vs Bill Singer: Career Stats Comparison
Jerry Koosman (1967–1985) and Bill Singer (1964–1977) — both came up during the 1960s, so the matchup is a direct one. Jerry Koosman compiled 222 wins and 2,556 strikeouts; Bill Singer put up 118 wins and 1,515 strikeouts. The numbers below run them through identical career and rate-stat lenses.
Jerry Koosman
Bill Singer
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 | Bill Singer |
|---|---|---|
| Wins | 222 | 118 |
| Losses | 209 | 127 |
| Games | 612 | 322 |
| Games Started | 527 | 308 |
| Complete Games | 140 | 94 |
| Shutouts | 33 | 24 |
| Saves | 17 | 2 |
| Strikeouts | 2,556 | 1,515 |
| Walks | 1,198 | 781 |
| Hits Allowed | 3,635 | 1,952 |
| Home Runs Allowed | 290 | 132 |
| Innings Pitched | 3,839 | 2,174 |
| ERA | 3.36 | 3.39 |
| WHIP | 1.26 | 1.26 |
| K/9 | 5.99 | 6.27 |
| BB/9 | 2.81 | 3.23 |
PIV Comparison
By PIV (Player Impact Value), Jerry Koosman outpaces Bill Singer 42,939 to 24,349 — a gap driven primarily by per-season impact (2,147 vs 1,623 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)
Bill Singer — top 3 seasons by ERA (lower is better)
Verdict
On the head-to-head card, Jerry Koosman leads in wins, strikeouts, ERA, and innings pitched, while Bill Singer owns WHIP and K/9. That doesn't settle the era debate, but on the raw scoreboard the edge goes to Jerry Koosman. PIV agrees: Jerry Koosman grades out higher across their careers. Click through to each profile for the full season-by-season breakdown.