He's actually in the same boat as Rooney, for me. I see absolutely no point in trying to criticise our Captains performances as he's been thrown around all over the pitch, and even when's he's played further forward, we lack creativity, which has seen him score only 12 goals, this season. di Maria, similarly, has played as a CM, LW, SS, RW, AM and due to this and a few other reasons, he's completely out of form.
With regards to who's fault it is, do you, for one moment, think that di Maria wants to play badly? Do you think he stepped out against WBA and thought "I'm going to ensure we lose this match"? He put in a fine ball to McNair, who should have scored (debate for another day), which is enough to show me that guy is trying is hardest to prove himself, but it isn't working out for one reason or another. His confidence is gone and won't return till he starts consistently.
It's the managers job to ensure he gets the best out of his players, and with regards to di Maria, he hasn't and LvG is responsible for that. Of course, that's not to say di Maria didn't help himself against Arsenal, for example, with the sending off, but who fecking cares about that - he made a mistake, we all do, I don't care about that, and neither should anyone else.