Manchester United are weighing up the option of making an approach in signing Aston Villa defender Ron Vlaar in January, according to the Guardian.

The Dutch international's future at Villa Park is up in the air as he is in his final six months of the contract. The centre-back has refused to sign an extension to continue with his current employers beyond this season.

Louis van Gaal has seen his side struggle defensively this season with injuries to several of his key players forcing him to change the formation regularly. Former United defender Paul McGrath had urged the Red Devils manager to sign his compatriot in the winter transfer window.

Vlaar has played under Van Gaal while the latter was managing the Netherlands, before stepping down from the position after the World Cup in Brazil. The 29-year-old was one of the key figures in the Dutch national team's three-man defence.

United allowed Rio Ferdinand and Nemanja Vidic to leave on free transfers and signed Marcos Rojo as the only centre-back in the last summer transfer window.

Vlaar knows Van Gaal's philosophy and also has the experience of playing in the Premier League, which will allow him to settle down quickly at Old Trafford, if he decides to make a switch.

United are yet to make contact with Villa over signing their skipper. They are likely to lose Vlaar either in January or at the end of the season. Paul Lambert was adamant that the club will not let the centre-half leave the club in the mid-season transfer window.

Failing to allow Vlaar leave in January will see Villa part ways with their defender for nothing later this year. Meanwhile, the Dutch defender has admitted that there has been no contact from United for his services.

"I've never heard from them. If a club had really wanted me, I would have noticed. That has not been the case," Vlaar told Dutch newspaper Algemeen Dagblad.