Regarding the pitcher in the OP, note that he didn't hit his full potential until he was 31. If the owner maintains a high training budget, it wouldn't surprise me if he maintained pretty healthy effectiveness through age 38 or so. Maybe the last year or 1.5 years of the deal he will decline but also look at where he's starting from; he'll be ML quality for the life of his contract with good training, I have little doubt.