Speaking to reporters ahead of the FA Cup game, Ten Hag said, "I am convinced he will be [a key player]. He didn't have the chance to prove this point, but he will be a very good player for Manchester United. It is really unfortunate, really disappointing for him, but also for us when you have such a class player in your middle and you cannot play him.
"He has had three injuries, as we all know, so he didn't, at any time, get into a rhythm. But I am sure when he is fit, he will play, he will get into that rhythm and he will contribute to a successful Manchester United."