no, I agree with what many people here said, Jose was trying to improve Mata so that he is a complete player (i.e improve his defence so that he's an even better asset in the big games [such as tough trips to Bernabeu, Camp Nou, Allianz Arena, Signal Iduna Park, Juventus Stadium etc]). Also Mata will now feel more pressure. I know he deserves a regular place but some players thing that they have a spot in the starting XI for granted. Even though Juan is an angel, at least Mourinho has sent his message across to the entire team, that no matter how good you are. IF you play shit, you won't play.