Manchester United winger Nani is set to miss the start of the new league season after dislocating his shoulder in the Community Shield defeat by Chelsea.
"He's out for a while, the worry is that we couldn't put it back in place," said United boss Sir Alex Ferguson after his side lost on penalties.
After scoring the game's opening goal, Nani had to come off just past the hour to be replaced by Antonio Valencia.
Nani dislocated his shoulder after he fell following a John Terry tackle.
The Portuguese winger is expected to take on greater responsibility in his team following the departure of Cristiano Ronaldo to Real Madrid.
He had an impressive game for United at Wembley, with his close ball control and speed troubling Chelsea in the first half.
Nani's goal came from a superb shot when he cut in from the left after 10 minutes.
But Chelsea recovered to take a 2-1 lead through goals from Ricardo Carvalho and Frank Lampard, before Wayne Rooney's injury equaliser sent the game to a shoot-out with Carlo Ancelotti's side triumphing 4-1.
Nani's injury will rule him of Portugal's friendly against Liechtenstein on 12 August.
He looks likely to miss next Sunday's Premier League opener against Birmingham City at Old Trafford, adding to United's problems.
Goalkeeper Edwin van der Saar is out of action for two months after undergoing surgery on a broken finger and bone in his left hand.
Nemanja Vidic has been ruled out for up to two weeks with a calf injury, although fellow defender Wes Brown - who missed the majority of last season with a foot injury - is expected to be fit to face Birmingham.
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