Welbeck is currently on a season-long loan at the Stadium of Light and has turned in a number of eye-catching performances.
The highly-rated 20-year-old's latest effort for the Black Cats came in Saturday's 1-0 win over Bolton as they climbed to sixth in the Premier League.
Bruce knows only too well that Sir Alex Ferguson is unlikely to give him what he wants, even if he was one of his ex-players, as they too see Welbeck making a big contribution for their side in the future.
The former United defender said: "I always knew that was going to be a problem anyway, deep down, but you never know.
"Fergie has got a birthday coming up shortly and he might get generous in his old age. But I somehow doubt it.
"He's a fantastic talent isn't he? You can see that and he has benefited from playing regularly.
"The good thing about him is he has got infectious enthusiasm about him. He wants to play and train and he has been terrific.
"Manchester United have got a very good player on their hands."