100% correct. Managers do small things that self-sabotage their tenures. If you do enough of them, you sink. Moyes has laid the early groundwork here and he's going to need a lot of luck not to see this Keane decision blow up in his face. One significant injury and Michael Keane is in play, not as a "reserve" but as a walking time bomb.
I hope I'm wrong, but I can see this manager coming under inordinate pressure by November. If he does, mark my words: Michael Keane will be central to his difficulties, and he'll have nobody else but himself to blame.