Season ERA
ERA (40+ IP)
| ERA | NAME | YEAR | |
|---|---|---|---|
| 0.78 | Adam Kiehl | 1993 (62 1/3 IP) | |
| 1.34 | Preston Johnson | 1991 (68) | |
| 1.36 | Jeff Donovan | 2006 (66 2/3) | |
| 1.66 | Andy Bergholz | 2000 (59) | |
| 1.70 | Jerry Volz | 1970 (41) | |
| 1.90 | Tim Meinecke | 1996 (51 2/3) | |
| 2.03 | Dan Sanft | 1974 (55) | |
| 2.14 | Vince LaBarbera | 1978 (72) | |
| 2.14 | Ed Eisenhauer | 1978 (40) | |
| 2.20 | Bill Dess | 1973 (70) | |
| 2.22 | Dennis McBride | 1972 (63) | |
| 2.23 | Justin Drabowicz | 2003 (53 1/3) | |
| 2.26 | Pat Bovee | 2002 (55 2/3) | |
| 2.29 | Adam Kiehl | 1992 (73 1/3) |