Speaking on Sky Sports, the former Red Devils captain said: "There's no confidence. He had a one-on-one with Konate and he's ended back up at centre-back. The United fans aren't going to let him get away with that. Whatever happens, you still have to go for it and take the one on one on.
"He might not be having a great day, great time, but he's just turned back and that tells you where his head is at. It's been going on for 14 months, he scored 30 goals the season before last. I'd like to think he can get his confidence back but it's looking like a struggle. The game doesn't look enjoyable for him right now and that's sad."
He added: "It's sad watching that kid because he has been a joy for United at times in his career but it is getting hard work for him and hard work for fans to watch him."