I don't pretend to have nearly enough knowledge on pitching mechanics or kinesiology to make very informed decisions on the subject so whatever the Sox decide to do will, IMO, be the correct decision. For all the things this organization does poorly, and that's quite a laundry list, they do seem to have a knack for developing pitching and protecting player's health.
That also said, the Rangers aren't exactly a slouch of a team, I'm sure Sale's not the first pitcher this season they've made look bad. If he starts getting lit up by the Astros and Marlins, OK, then maybe I'll wonder. In 2 of his last 3 starts, Sale's shut down the Tigers and Yankees, so at this point, it seems prudent to think yesterday was the exception and not the rule.
Also, finally, Sale did struggle last September, and I'd personally prefer he learn how to keep stretching out and lasting a full season in a wasted year, rather than have him melt down again late in a meaningful season.