The Italian joined the west Londoners in January during Neil Warnock’s reign. However, within a matter of weeks the Yorkshireman was replaced by Mark Hughes.
Unfortunately for Macheda, he was not in the Welshman’s plans but he did not help matters when he was fined £15,000 by the Football Association for posting a homophobic Tweet.
He has recently returned to United for treatment on an ankle injury, ending his loan spell with QPR.
It is now the second time the 20-year-old has endured a frustrating loan spell after his stint at Sampdoria saw a changeover in managers within weeks of his arrival, but Sir Alex feels luck is not on the striker’s side.
“He's so unlucky," Sir Alex told MUTV, "I have complete belief in the boy. He could be an outstanding player, but he needs football.
“We put him on loan to Sampdoria last January. He was there for two weeks, they sacked the coach and he didn't get a game.
“We put him on loan to QPR. Two weeks later they sack the coach and he didn't get a game.
“That has been really unfortunate.”
However, Macheda will have to wait until next season to play again after the 70-year-old revealed the attacker is to undergo surgery.
“He has been bothered with his ankle a little bit over the last few weeks, so we have done the right thing to get an operation and hopefully he will be ready for next season,” he said.
The former Lazio youth player joined United in 2007 and has made 19 appearances for the Red
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