Fred Mitchell vs. Bob O'Brien — Career Comparison

Looking at the career totals, Fred Mitchell and Bob O'Brien are fairly close on the surface numbers. Bob O'Brien posted stronger numbers in ERA (3 vs 4.1) and WHIP (1.333 vs 1.544). Fred Mitchell had the advantage in home runs allowed (0.2 per nine innings vs 0.86). By the career numbers, Bob O'Brien had the better of this comparison — though ERA and WHIP alone don't account for era, park factors, or the defenses each pitcher worked behind.