John Milligan vs. Sean O'Sullivan — Career Comparison

Looking at the career totals, John Milligan and Sean O'Sullivan are fairly close on the surface numbers. John Milligan posted stronger numbers in ERA (5.17 vs 6.01) and home runs allowed (0.15 per nine innings vs 1.64). Sean O'Sullivan had the advantage in WHIP (1.616 vs 1.783). By the career numbers, John Milligan 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.