Jack Aker vs. Mark Prior — Career Comparison

Mark Prior built a career as a starting pitcher and Jack Aker as a reliever — different jobs with different demands — but on the metrics that apply to both, a comparison is still worth making. Mark Prior led in strikeout rate (K%+ 170 vs 86), skill-based run prevention (DICE+ 137 vs 88), and run prevention (ERA+ 133 vs 89). Role difference aside, Mark Prior holds a clear edge on every meaningful shared measure.