ERA
Jeff Suppan · Season-by-season history
ERA over time
- Boston Red Sox · MLB
- Kansas City Royals · MLB
| Season | Team | League | ERA |
|---|---|---|---|
| 2003 |  Boston Red Sox |
MLB | 5.57 |
| 2002 |  Kansas City Royals |
MLB | 5.32 |
| 2001 | Kansas City Royals |
MLB | 4.37 |
| 2000 | Kansas City Royals |
MLB | 4.94 |
| 1999 | Kansas City Royals |
MLB | 4.53 |
| 1998 | Kansas City Royals |
MLB | 0.71 |
| 1997 | Boston Red Sox |
MLB | 5.69 |
| 1996 | Boston Red Sox |
MLB | 7.54 |
| 1995 | Boston Red Sox |
MLB | 5.96 |