Last season, Merrill Kelly was a clear # 2 in the rotation, with the second best FIP and the best ERA. His percentage of quality starts was tied for the 14 th/15th best in the Majors. He and Gallen were the best in five measures of pitching consistency.
When I looked at the ZiPS projection for the Diamondbacks’ starting pitchers (including the newly acquired Eduardo Rodriguez), I compared projected ERA for next season to actual ERA in 2023. The biggest worsening was Merrill Kelly (3.97 projected ERA vs 3.29 actual ERA). What made that especially surprising is that a big characteristic of Merrill Kelly is consistency.