Speaking to talkSPORT, Yorke said: "I think optimistic is probably the right word at this moment in time. When you go to United and you get off to a very bad start, which he did, you just question whether he’s ever going to return [the goals]. He’s young, he’s playing in a team that is struggling and is inconsistent, so it’s very difficult circumstances for him to come into, especially with such a big price tag.
"That’s a lot to ask of a young man. But with a bit of perseverance, he’s showing signs. He’s still not convincing enough for me at the moment but I’m happy that he’s at least got some goals."