John Callahan vs. Zack Weiss — Career Comparison

Looking at the career totals, John Callahan and Zack Weiss are fairly close on the surface numbers. Zack Weiss posted stronger numbers in ERA (4.61 vs 16.2) and WHIP (1.280 vs 3.000). John Callahan had the advantage in home runs allowed (2.16 per nine innings vs 2.63). By the career numbers, Zack Weiss 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.