Diego Moreno vs. William Pierson — Career Comparison

Looking at the career totals, Diego Moreno and William Pierson are fairly close on the surface numbers. William Pierson posted stronger numbers in ERA (3.38 vs 5.06) and home runs allowed (0 per nine innings vs 1.13). Diego Moreno had the advantage in WHIP (1.250 vs 1.969). By the career numbers, William Pierson 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.