ALEX Ferguson, the Manchester United manager, fears that he will lose Nemanja Vidic next summer.

Barcelona and Real Madrid want to take Vidic to Spain while the Serbia defender is also being tracked by AC Milan in Italy.

Ferguson will try to talk Vidic out of leaving, but he is understood to be genuinely concerned that the player may have had his head turned by the idea of a move to the Continent and is unsure that even the offer of a lucrative new contract would be enough to persuade the 27-year-old to stay.

Vidic denied reports in August that his wife, Ana, is unhappy in Manchester amid speculation about his future, but it is thought that the wishes of his family will have a significant bearing on any decision.

United, who face Besiktas in their penultimate Champions League group B match at Old Trafford this evening, are in a strong position, however. With Vidic contracted to the club until June 2012, Ferguson would be able to demand a huge fee for the centre back if the manager decided a parting of ways was the only route forward.

Given some of the exorbitant transfer fees last summer, it is unfeasible United would let Vidic leave for anything less than £30m -- more than four times what they paid Spartak Moscow for him in January 2006.

Vidic was ambiguous on the subject of his future in an interview this month with Red News, the United fanzine. Asked if he might see out his career at Old Trafford, Vidic said: "You never know what is going to happen. I can't say what is going to happen in one year, two years' time.

"At the moment, I'm happy and I'm here. (Let's) see what the club is going to say, what it is going to be.

"I want to play well here and for the fans and everyone to be happy with me. To see that I give the right effort, give my best, give 100 per cent. That is important to me.

"What is going to happen in the future, no one knows. I definitely have two and a half years (left on my) contract here and I will stay here."

After a poor start to the season, albeit one disrupted by injury, Vidic was back to his best in the 3-0 Premier League win at home to Everton last Saturday.

Ferguson has considerable faith in Jonny Evans, the Northern Ireland centre back, and Wes Brown, who will line up alongside Vidic against Besiktas.

But with Rio Ferdinand struggling with a long-term back problem that has become a serious cause for concern, the prospect of losing the tough-tackling Serb is a headache the United manager could do without.

John O'Shea can also operate at centre half in an emergency, but the departure of Vidic would almost certainly necessitate the purchase of another defender.

Jack Rodwell, the Everton utility player, has been identified by United as a star of the future. Rodwell, 18, is being used primarily as a holding midfield player, but some view him as a central defender in the longer term. Everton, though, will fight tooth and nail to keep the player, who signed a new five-year contract only in February and is not thought to be in any rush to leave Goodison Park.

Knockout

With qualification to the Champions League knockout stages already assured, Ferguson is expected to give some of his younger players -- Ben Foster, the goalkeeper, Rafael Da Silva, the right back, and Darron Gibson and Gabriel Obertan, the midfield players -- another run-out against Besiktas.

Ferguson said: "Finishing first or second in the group I don't think carries so much importance, but I want to win the group because it is the best thing to do.

"Besitkas' form has been transformed. They have won their last seven matches and beat the team (Fenerbahce) that's top of the Turkish league 3-0 on Saturday, so they are showing very good form.

"It's a good fixture because of that. I can try one or two things. It is a great challenge for these young players -- Gibson, Rafa.

"Sometimes you can't hold a young man back and that time is approaching for Darron now. He is becoming a good, powerful midfield player."

© The Times, London

MAN UTD v BESIKTAS, ITV1/RTE2, KO 7.45

- James Ducker