Charlie Kerfeld vs. Oswaldo Mairena — Career Comparison

On the career pitching numbers, Charlie Kerfeld posted a stronger line than Oswaldo Mairena. Charlie Kerfeld posted stronger numbers in ERA (4.2 vs 6.06) and WHIP (1.572 vs 1.654). By the career numbers, Charlie Kerfeld 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.