John Costello career ERA
2.97Career Regular Season
John Costello has a career ERA of 2.97 over 4 regular seasons.
- Best season on file: 1.81 in 1988.
- Most recent: 3.09 in 1991.
Figures come from ESPN's box scores and were last read on September 22, 2026.
| GP: Games the player appeared in, however briefly. | W: Games in which this pitcher was credited with the win. | L: Games in which this pitcher was charged with the loss. | ERA: Earned runs allowed per nine innings pitched — lower is better. Under 3.00 is excellent. | IP: Innings pitched. The decimal counts outs, so 6.2 is six innings and two more outs. | K: Batters this pitcher struck out. | BB: Times the batter reached first base on four balls. | WHIP: Walks and hits allowed per inning pitched — lower is better. Around 1.00 is elite. | SV: Games finished by protecting a narrow lead to the last out. | ||
|---|---|---|---|---|---|---|---|---|---|---|
| 1988 |  STL | 36 | 5 | 2 | 1.81 | 49.2 | 38 | 25 | 1.39 | 1 |
| 1989 | STL | 48 | 5 | 4 | 3.32 | 62.1 | 40 | 20 | 1.09 | 3 |
| 1990 |  STL/WSH | 8 | 0 | 0 | 5.91 | 10.2 | 2 | 2 | 1.31 | 0 |
| 1991 |  SD | 27 | 1 | 0 | 3.09 | 35.0 | 24 | 17 | 1.54 | 0 |
What the columns mean: W · L · ERA · IP · K · BB · WHIP · SV