Jack Aker vs. John Duffie — Career Comparison

John Duffie 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. John Duffie posted stronger surface numbers — ERA 2.79 and WHIP 1.655 compared to 3.28 and 1.369 for Jack Aker. By the career numbers, John Duffie had the better of this cross-role comparison — though era context would sharpen the verdict.