Manchester United manager Sir Alex Ferguson has ruled out making any signings in the January transfer window.
"No, not at all, definitely not," Ferguson said when asked if he would dip into the market when the window opens on Saturday.
Welbeck has blossomed under the guidance of Steve Bruce at the Stadium of Light, scoring five goals in 18 league appearances this season.
Macheda is expected to make be loaned out to a Serie A team, and Ferguson is hopeful the Italy Under-21 international will benefit from getting extra games under his belt.
"I had a chat with the boy, I think he is in the same position as Welbeck and Mame Diouf," Ferguson said. "They are young and they need games and Kiko falls into that category now.
"It can pan out exactly the same for him. It would be the same thing, going to a club, getting that experience for six months and coming back to us a better player.
"The reason we let Danny Welbeck and Mame Biram Diouf go was that they are young and they need games. And with Welbeck it has proved the point that through consistent, regular football, you can progress dramatically."
Meanwhile, midfielder Paul Scholes is expected to return to training soon after continuing his recovery from a groin problem.
"Paul had a little recurrence of the groin injury,'' Ferguson said. "We just told him to have a complete break, which is what he has done. Hopefully that break will get rid of the injury problem through rest and we will have him back training sometime next week.''