Kenley Jansen vs. Lou Mahaffey — Career Comparison

Looking at the career totals, Kenley Jansen and Lou Mahaffey are fairly close on the surface numbers. Kenley Jansen posted stronger numbers in ERA (2.57 vs 3) and WHIP (0.983 vs 1.667). Lou Mahaffey had the advantage in home runs allowed (0 per nine innings vs 0.85). By the career numbers, Kenley Jansen 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.