The Italian striker burst onto the scene in April 2009, when, as a 17-year-old, he scored a superb stoppage-time winner in a 3-2 victory at home to Aston Villa in the Premier League.

He was rewarded with a four-year contract by former United manager Alex Ferguson, but has spent most of the last three years on loan.

Following spells at Sampdoria, Queens Park Rangers, Stuttgart and Doncaster Rovers, he joined second-tier Birmingham City in January and has scored three goals for the club in his first six games.

"I don't think I will stay at United, but whatever happens, nobody can take away the memories of my time there," the 22-year-old told The Daily Telegraph.

"Sir Alex was amazing for me; he believed in me so much. After I scored two goals against Charlton last month he sent me a text message straight after the game.

"That was incredible because I hadn't spoken to him for a long time, so to get that text was a relief. He said 'Well done and keep going.'"

Macheda has scored four goals in 19 games for United, but last played for the club in December 2012.