The defender Nemanja Vidic, who suffered a serious knee ligament injury, will no longer play this season.
The 30-year-old footballer got injured during Wednesday's Champions League match against Basel, when he collided for the ball with opponent Marco Streller.
"Nemanja is out of the squad until next season," said coach Sir Alex Ferguson. "This is bad news, a big loss. Given the episode of the injury, we could expect something like this."
He added: "On Monday, Vidic will meet with a specialist to discuss rehabilitation after the operation. But first, we need to wait for the swelling to go down."
In the weekend's English Premier League match against Wolverhampton, there may be up to nine injured players in the ranks of the 'Red Devils': besides Vidic, out of the squad are Michael Owen, Anderson, Tom Cleverley, Fabio, Rafael, Javier Hernandez, Ashley Young, and Dimitar Berbatov.
Vidic's injury: