Mark Mercer vs. Juan Then — Career Comparison

Looking at the career totals, Mark Mercer and Juan Then are fairly close on the surface numbers. Mark Mercer posted stronger numbers in ERA (4.7 vs 4.91) and home runs allowed (1.17 per nine innings vs 2.45). Juan Then had the advantage in WHIP (1.455 vs 1.826). By the career numbers, Mark Mercer 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.