Manchester United manager Louis van Gaal has confirmed Marcos Rojo suffered a dislocated shoulder in the 1-0 defeat to Manchester City at the Etihad Stadium.
Rojo was stretchered off early on in the second half and needed gas and air when going off the pitch after landing awkwardly on his shoulder in making a sliding challenge.
The Argentine is now facing a spell on the sidelines to add to United's defensive problems with Rafael and Phil Jones out injured and Chris Smalling facing a ban following his sending-off against City.
"The shoulder is out, so you never know how long that takes," Van Gaal told Sky Sports. "I have to wait until tomorrow but he shall not play against Crystal Palace."
Despite United's growing injury list van Gaal is refusing to make excuses feeling they have a big enough squad to cope without the missing players.
"We have injuries but we still have 11 players to play and they are very good players," added van Gaal.
"I don't cry for that, but it is sometimes difficult to select the best team. I think I can manage that."
Rojo is hopeful, though, that he will not be out of action too long as he later tweeted that the injury was 'not serious'.
"Thank you all for your messages. Thank god it was nothing," he wrote on Twitter.