Aston Villa boss Paul Lambert cannot guarantee keeping hold of skipper Ron Vlaar.

The Dutch international continues to be linked with a move to Manchester United, where he would be reunited with his former Holland manager Louis van Gaal.

He is out of contract in the summer - leading to suggestions that Villa could cash in on him in January, rather than lose him for nothing at the end of the season.

Lambert concedes Dutch captain "holds the card" six months before his contract expires at Villa Park.