Art Mahaffey vs. Bill Williams — Career Comparison

On the career pitching numbers, Art Mahaffey posted a stronger line than Bill Williams. Art Mahaffey posted stronger numbers in ERA (4.17 vs 5.06) and home runs allowed (1.13 per nine innings vs 1.69). By the career numbers, Art Mahaffey 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.