Nemanja Vidic has undergone knee surgery and will be unavailable for eight weeks, Manchester United have announced.
An official statement by the club stated: "Nemanja Vidic has had a meniscus operation on his right knee and will be out for around eight weeks."
"Manchester United manager Sir Alex Ferguson rested Vidic as a precautionary measure at the weekend after he complained of tightness in his knee. However, further medical investigation revealed the underlying problem."
The Red Devils captain missed United's 2-1 win against Liverpool at Anfield on Sunday after a complaint with his right knee, but on examination was found to have a more serious problem and was sent for surgery, which has now been completed.
Vidic missed the last five months of last season with a ruptured cruciate knee ligament. Ferguson had complained of his side's injury woes already this season, particularly in defence, where despite United's strength in depth, they have struggled, with Michael Carrick already having to fill in at centre-back on one occasion this season.