Yilber Díaz vs. John Perkovich — Career Comparison

Yilber Díaz built a career as a starting pitcher and John Perkovich as a reliever — different jobs with different demands — but on the metrics that apply to both, a comparison is still worth making. Yilber Díaz posted stronger surface numbers — ERA 4.31 and WHIP 1.468 compared to 7.2 and 1.600 for John Perkovich. By the career numbers, Yilber Díaz had the better of this cross-role comparison — though era context would sharpen the verdict.