Look at palmer, foden, Lewis, bobb.... they all sit in and around the match day squad for a while, a season at least, before being integrated, and even then it's slowly slowly. Palmer didn't like it, took his chance, and ok he's taken it well.
I realise McAtee has more senior experience, and that might speed up the process a touch, but he has to look at the above players and not expect the earth too soon (and I reckon he's been fully briefed!!). He'll get his chances, we have to trust Peps slow integration of these lads.