John Allen vs. Aaron Heilman — Career Comparison

Looking at the career totals, John Allen and Aaron Heilman are fairly close on the surface numbers. Aaron Heilman posted stronger numbers in ERA (4.4 vs 18) and WHIP (1.402 vs 2.000). John Allen had the advantage in home runs allowed (0 per nine innings vs 1.03). By the career numbers, Aaron Heilman 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.