John Perkovich vs. David Robertson — Career Comparison

On the career pitching numbers, David Robertson posted a stronger line than John Perkovich. David Robertson posted stronger numbers in ERA (2.93 vs 7.2) and WHIP (1.204 vs 1.600). By the career numbers, David Robertson 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.