Gabriele Marcotti in todays Times discusses the sacking of Ancelotti.He quotes Uli hoeness the Bayern president "as a manager you can't have the prominent players in your team against you......I'e learned an important lesson in life:your most dangerous enemy is the one right there in your bed....."
I would suggest Pedro was aware of the risk with Miller and tried to keep him on side with lots of game time, but alas to no avail.