Earned run average
From BR Bullpen
A pitcher's Earned Run Average (aka ERA) is a primary measure of his success. It is expressed as an average number of opponents' earned runs scored per notional nine inning game:
- ERA = Earned Runs Allowed * 9 / Innings Pitched
| All Time Leaders | |||
|---|---|---|---|
| Span | Player | Total | Notes |
| Career | Ed Walsh | 1.82 | |
| Season | Tim Keefe | 0.86 | 1880 |
| Season (since 1920) | Bob Gibson | 1.12 | 1968 |
| NPB Career | Hideo Fujimoto | 1.90 | |
| NPB Season | Hideo Fujimoto | 0.73 | 1943 |
| KBO Career | Dong-yol Sun | 1.20 | |
| AAGPBL Career | Jean Faut | 1.23 | |
| AAGPBL Season | Lois Florreich | 0.67 | 1949 |
| MLB Career minimum 1000 innings | |||
