Welbeck has already welcomed Robin van Persieâ€™s arrival and while the Manchester-born youngster may not feature in every game this season, heâ€™s certain to benefit in the long term by working alongside such a varied array of forwards.
Sir Alex said: "I saw his interview and it was very refreshing. He started talking about scoring more goals â€“ I hope he's right!
"At 21 he's a young boy. He's still growing and has niggles, but heâ€™s going to be a big boy. He won't play every week but when he's 23 or 24 heâ€™ll be a fantastic player."