Bill Castro vs. Michael Kopech — Career Comparison

Michael Kopech built a career as a starting pitcher and Bill Castro as a reliever — different jobs with different demands — but on the metrics that apply to both, a comparison is still worth making. Bill Castro led in walk avoidance (BB%+ 140 vs 58), home run suppression (HR9+ 111 vs 83), and skill-based run prevention (DICE+ 96 vs 78). Michael Kopech held the edge in strikeout rate (K%+ 100 vs 66). Role difference aside, Bill Castro holds a clear edge on every meaningful shared measure.