Nemanja Vidic's future at Manchester United in doubt as Real Madrid prepare to pounce

Nemanja Vidic's future at Manchester United has been plunged into fresh doubt.

Sir Alex Ferguson has admitted that he could not deliver a firm answer of Vidic when asked about the possibility of him moving on this summer.

Waving goodbye? Alex Ferguson could lose Nemanja Vidic this summer

Waving goodbye? Alex Ferguson could lose Nemanja Vidic this summer

The centre-back is a long-term target for Real Madrid and his wife is believed to be keen on leaving England.

When asked about speculation that 28-year-old Vidic would leave Old Trafford, Ferguson replied: 'I can't clarify it at all.'

Wanted man: Vidic

Wanted man: Vidic

After being pressed on the matter and asked if Vidic would line up for them this season, Ferguson replied: 'I believe so.'

Vidic is again on the radar of Real Madrid - now managed by Jose Mourinho - as they rebuild for the new season.

Despite on going doubts over his future, Vidic has remained loyal to United and last season he insisted he would see out his contract that runs until 2012.

But Ferguson's comments will leave United fans fearing that they will lose another big name after the departure of Cristiano Ronaldo and Carlos Tevez last summer.

Vidic is the long-term defensive partner of Rio Ferdinand, although Jonny Evans has emerged as a serious contender to take over in the near future.