Key word here is he's playing together with Oscar. Mata started the season as 2nd choice, fair enough. Oscar was really good at the start, so Mata couldn't get a look-in, fair enough. But the job of back-ups is to come in as part of rotation or when the player in their position isn't playing well, yet 95% of the times Mata has started in meaningful games, it has been alongside Oscar. And they both share the same position and make our already average attack worse. So Mata as usual gets the blame, and back to the bench.