| Season |
Year |
ERA |
| Mike Grover |
1978 |
0.52 |
| Jake Lewis |
2012 |
0.65 |
| Nik Peterson |
1981 |
0.77 |
| Jim Masterson |
1972 |
0.84 |
| Lee Stephenson |
1985 |
1.19 |
| Dennis Gulbranson |
1978 |
1.21 |
| Bill Richardson |
1981 |
1.30 |
| Dale Nikko |
1975 |
1.32 |
| Dale Nikko |
1978 |
1.47 |
| Ray Miles |
1982 |
1.58 |
| Rick LaLonde |
1987 |
1.65 |
| Dale Nikko |
1976 |
1.67 |
| Jim Masterson |
1971 |
1.70 |
| Jason Malec |
1980 |
1.71 |
| Dale Nikko |
1977 |
1.72 |
| Jake Lewis |
2010 |
1.88 |
| Chris Nylund |
1990 |
1.93 |
| Ben Nelson |
2012 |
1.96 |
| Chris Kindgren |
1987 |
1.99 |
| Rick LaLonde |
1986 |
2.05 |
| Ray Sandstrom |
1984 |
2.06 |
| Jim Masterson |
1970 |
2.10 |
| Chris Kindgren |
1985 |
2.13 |
| Bill Moen |
1971 |
2.18 |
| Nik Peterson |
1980 |
2.26 |
| Alex Oachs |
2011 |
2.26 |
| Bill Moen |
1972 |
2.31 |
| Jay Anderson |
1982 |
2.37 |
| Jake Lewis |
2011 |
2.42 |
| B. Gales |
1975 |
2.46 |
| Jack Nikko |
2012 |
2.47 |
| Mike Grover |
1977 |
2.55 |
| Ben Nelson |
2011 |
2.55 |
| Dennis Gulbranson |
1977 |
2.57 |
| Kyle Cotrell |
2007 |
2.61 |
| Blake Reinke |
2006 |
2.73 |
| Brian Mrozik |
1990 |
2.76 |
| James Ostrander |
2009 |
2.78 |
| Chris Kindgren |
1986 |
2.79 |
| Alex Oachs |
2010 |
2.87 |
| Bill Moen |
1973 |
2.88 |
| Steve Makitalo |
1983 |
2.92 |
| Alex Oachs |
2009 |
3.00 |
|
| Career |
ERA |
| Ray Miles (1981-82) |
1.28 |
| Dale Nikko (1975-78) |
1.60 |
| Jake Lewis (2009-12) |
1.60 |
| Jim Masterson (1970-72) |
1.64 |
| Rick LaLonde (1985-87) |
1.83 |
| Nik Peterson (1979-81) |
1.95 |
| Mike Grover (1975-78) |
2.33 |
| Chris Kindgren (1985-87) |
2.33 |
| Jay Anderson (1981-82) |
2.35 |
| Chris Nylund (1989-90) |
2.47 |
| Bill Moen (1971-73) |
2.50 |
| Ben Nelson (2010- |
2.53 |
| Alex Oachs (2008-11) |
2.80 |
| Dennis Gulbranson (1976-79) |
2.86 |
| Kevin Schubert (2006-08) |
2.99 |
|
