Roberto Rivera vs. Zack Weiss — Career Comparison

Looking at the career totals, Roberto Rivera and Zack Weiss are fairly close on the surface numbers. Roberto Rivera posted stronger numbers in ERA (4.5 vs 4.61) and home runs allowed (1.5 per nine innings vs 2.63). Zack Weiss had the advantage in WHIP (1.280 vs 1.583). By the career numbers, Roberto Rivera 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.