This belief that he is used to a slow, unphysical, possesion based game is utter nonsense. He came to fame playing for Benfica, who don't remotely play like that. Despite the common belief, Portuguese football is nothing like Spanish football. They play all out attack with vast amounts of runners from midfield. He was at his best playing as the holder, giving Gaitan, Witsel, Salvio, Bruno Cesar and co the licence to fly forwards, along with both fullbacks. The problem he's had so far is that unlike Witsel, Yaya has made no attempt to get back or help out defensively, meaning he's gotten overloaded.
You simply cannot play a midfield 2 if one of them isn't defending, it will make the one player chasing shadows look poor, while the lazy guy is strolling around so far away from the play they avoid the blame. Let him play alongside someone with energy like Fernandinho, Rodwell or Milner, or play him in a midfield 3, then he can be a top player for us, but if we hang him out to dry playing in a two with Yaya then he'll get continue to get exposed
