I'll give Miggy a mulligan on this season. He wasn't 100% and has been one of the best hitters in the MLB for the past decade. Sure he could be slowing down, as every aging slugger does, though I wouldn't completely write him off just yet after one bad injury-plagued season. If he continues to be below replacement level again in 2018, then we can make that argument.
Regardless, the contract even at the time when it was handed out likely was a mistake and there was a good chance that the latter part of the deal was going to be like throwing money out the window. So even then, there was the potential for it to be the worst contract in baseball.