Dan O'Brien vs. Mark Prior — Career Comparison

Mark Prior built a career as a starting pitcher and Dan O'Brien as a reliever — different jobs with different demands — but on the metrics that apply to both, a comparison is still worth making. Mark Prior posted stronger surface numbers — ERA 3.51 and WHIP 1.240 compared to 5.9 and 1.931 for Dan O'Brien. By the career numbers, Mark Prior had the better of this cross-role comparison — though era context would sharpen the verdict.