Adam Peterson vs. Bill Pierro — Career Comparison

Looking at the career totals, Adam Peterson and Bill Pierro are fairly close on the surface numbers. Adam Peterson posted stronger numbers in ERA (5.46 vs 10.55) and WHIP (1.516 vs 2.103). Bill Pierro had the advantage in home runs allowed (0.62 per nine innings vs 1.39). By the career numbers, Adam Peterson 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.