Not having heard anything Hinch has said about this, my guess would be he was trying to balance the scales between getting as much as he possibly could out of Skubal, and not completely ruining his arm in advance of the ALCS. And hey, it almost worked. In fact, he could have gone the seventh, and he could have gone the eighth, but he would have to have come out anyway, because no way he was going fifteen.
Apropos of nothing, I never noticed before that you put a space before your punctuation.