David Aardsma vs. Michael Kohn — Career Comparison

Looking at the career totals, David Aardsma and Michael Kohn are fairly close on the surface numbers. Michael Kohn had the edge in ERA (3.52 vs 4.27). By the career numbers, Michael Kohn 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.