They way he is so rigid in his instructions, which has been brought up at length, not favouring creative freedom at the expense of rigid patterns etc, is probably reflected on how he thinks players should train.
So he may favour those who put a shift in training like he did - like Laca, Xhaka, Willian, etc., and not the more mercurial ones who you can see goofing off in training (Gendouzi, Ozil, AMN) or not fully getting what he wants like Pepe. I suspect guys like Auba and Saka also probably are pretty committed.
My operating theory is therefore that he has a very fixed view of what a successful player in his system should be and additional to what he should do. And of course, that can work, but you have to come up with results. He did for a short while, but now that he doesn't, he's being exposed for it.
