Sir Alex Ferguson confirmed on Friday that Manchester United captain Nemanja Vidic has been ruled out for the rest of the season with a knee injury.
Vidic suffered a ruptured cruciate ligament when he tangled with Marco Streller during the first half of United's shock 2-1 Champions League defeat at Basel on Wednesday.
The Serbia centre-back left the stadium on crutches, with his agent Silvano Martina hinting on Thursday that he would be sidelined for several months.
Ferguson had been desperately hoping Vidic would be back in only a few weeks.
But Vidic underwent scans on his right knee on Thursday and Ferguson revealed the 30-year-old's injury is serious enough to keep him out for the remainder of the campaign.
"Nemanja is out for the season. It is bad news. He will be a loss," Ferguson said on Friday.
"I thought it was a bad one when I saw it. He sees the specialist on Monday to map out the progress of when he has the operation.
"It won't be immediate because we have to let the swelling come down. It's not unexpected but it is a bit of a blow."
Vidic's absence is a significant setback to United's hopes of retaining the Premier League title.
With United already reeling from their surprise exit from the Champions League, Ferguson could have done without Vidic joining Rafael and Fabio Da Silva, Anderson, Tom Cleverley, Javier Hernandez, Dimitar Berbatov and Michael Owen on United's growing injury list.
He will have to hope Rio Ferdinand can improve his shaky form and establish a partnership with one of Phil Jones, Chris Smalling or Jonny Evans at the heart of United's defence.