Jonathan Aro vs. John Shaffer — Career Comparison

On the career pitching numbers, John Shaffer posted a stronger line than Jonathan Aro. John Shaffer posted stronger numbers in ERA (4.57 vs 6.55) and WHIP (1.492 vs 1.909). By the career numbers, John Shaffer 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.