THE tension between Nemanja Vidic and Alex Ferguson has heightened after the Manchester United defender's last-minute withdrawal from the team humbled by Leeds United.
There was already discord between the player and the club over his contractual demands, with Vidic seeking to become one of the best-paid members of the squad on more than £100,000 a week.
Ferguson fears that the Serbia centre half is using the stand-off to engineer a move to Real Madrid.
That unease increased on Sunday, when Vidic pulled out of the humiliating FA Cup third-round defeat at Old Trafford with an injury suffered in the warm-up, prompting Ferguson and Mike Phelan, the assistant manager, to speak in almost dismissive terms about the player's absence.
Vidic's withdrawal is understood to relate to a recurrence of the calf injury that has troubled him periodically since October and led him to leave the pitch as a precautionary measure towards the end of the 5-0 victory over Wigan Athletic on Wednesday.
Paolo Fabbri, one of Vidic's representatives, said last night that he was not aware of a new injury to the player and that he believed Vidic will be fit to face Manchester City in the Carling Cup semi-final, first leg tomorrow.
Fabbri also attempted to play down the notion of a rift between Vidic and the United manager, saying that the defender would not leave United unless the club wants him to. But there have been growing signals from within Old Trafford that a parting of the ways is beginning to look inevitable.
Real have enjoyed great success in signing players from United in recent years -- David Beckham, Gabriel Heinze, Ruud van Nistelrooy and, most recently, Cristiano Ronaldo -- and would relish the opportunity to sign Vidic to address their defensive shortcomings, which Ferguson has been only to keen to point out.
United would look for at least £25m for the 28-year-old, with players such as Simon Kjaer, of Palermo, and Bruno Alves, of Porto, likely to figure as possible replacements.
United are insistent that Vidic, who is understood to earn approximately £70,000 a week, is not in a position to demand a new contract, given that his deal, which was improved and extended two years ago, runs until 2012.
They are concerned that the player's head has been turned by soundings from Real after previous interest from Barcelona and Bayern Munich. He joined United from Spartak Moscow for £7m four years ago.
Vidic and his representatives, for their part, believe that his rise in status since he signed his last contract, in November 2007, merits a new deal at Old Trafford.
He was on the shortlist for the Fifa World Player of the Year award last month and named in the FIFPro team of the year, although his form is widely acknowledged to have dipped below the levels of 12 months ago, even if Ferguson described his performance against Wigan last week as "magnificent".
When pressed on why Vidic pulled out of Sunday's match, Ferguson only said: "I couldn't tell you. I couldn't tell you at all."
It remains to be seen whether Vidic will play against City tomorrow, but Ferguson has indicated he will make wide-reaching changes to the team that lost to Leeds.
Rafael Da Silva, Patrice Evra, Darren Fletcher, Michael Carrick and Ryan Giggs look certain to return to the squad, with Ferguson willing to abandon his usual Carling Cup selection policy to ensure that defeat by Leeds is not followed by further embarrassment at the hands of their cross-city rivals.