Well, answering that would require a widely accepted objective standard. His team improved by six games in his first season and then regressed by 22 games. They steadily improved incrementally over the next three seasons, but never reached .500 again. To his credit, I guess, his tenure ended with his resignation, initiated by him, rather than his firing. On the other hand, they regressed starkly again this year in their first season without him, so maybe he needs to wear a "quitter" label. His last year was marred by two kinda-ugly-but-kinda-colorful clubhouse incidents, one in which Chris Sale cut up the throwback jersey that he didn't want to wear for a start, and bitched that Ventura wouldn't back him, and another in which VP Ken Williams banned DH Adam Laroche's son from the clubhouse during spring training. I concluded that these probably precipitated his departure. PLAYER REVOLT is a tough thing for a manager to have on his LinkedIn page.