Manchester United have been dealt a huge blow with the news that Nemanja Vidic has been ruled out for eight weeks.
The Red Devil's captain underwent surgery after missing the weekend's match against Liverpool after complaining of tightness in his right knee.
At first the complaint was not considered serious, but further examination showed the need to undergo an operation.
In a statement on the club's website, Manchester United said: "The central defender was operated on this week and will be sidelined for about eight weeks."
The centre back missed the final five months of last season after rupturing his cruciate in the same knee during a Champions League defeat to Basle.
Should Vidic return in the time frame set out by United, it will still mean the defender misses three Champions League games and Premier League matches against Chelsea and Arsenal.
Ferguson will be hugely disappointed to lose yet another defender to injury, with the United manager already struggling to fill places at the back.
Phil Jones is expected to be out for another two months, Chris Smalling is not currently training with the squad after breaking a metatarsal and Jonny Evans picked up a knock at Anfield.
Rio Ferdinand is the only remaining recognised centre-back, yet the England defender has been plagued by injuries in recent years and if forced to play every game in Vidic's absence, will be at risk.
Michael Carrick, who has been used at centre-back in the past, could be called upon. Alternately, youngsters Michael Keane and Scott Wooton, both of whom may feature in the Capital One Cup tie against Newcastle tomorrow, could be forced to step up. Keane has made one substitute appearance while Wooton is yet to make his debut.