By North-west correspondent Alex Stevens

Louis van Gaal admitted he is in the market for a new full-back this month after Manchester United’s latest crushing injury blow.

Ashley Young has been ruled out for “a long time” by the Dutchman with a severe groin injury sustained in last weekend’s 1-0 win at Liverpool.

Van Gaal said the former England international will go under the knife to cure the problem and he is now facing months out.

Young has become the fourth senior United full-back to be sidelined with a serious injury, alongside Luke Shaw, Marcos Rojo and Antonio Valencia.

Speaking on Friday afternoon at his media conference, Van Gaal revealed he is keen to recruit a new full-back in the January window.

“When you see our luck with the full-backs this season, only [Matteo] Darmian is fit,” said the manager. “I need full-backs.

“We have started with Valencia, Shaw, Rojo, Darmian and Young, sometimes, and they are all injured – only Darmian is now back.

Injury blow: Young will undergo groin surgery and is facing months out

Injury blow: Young will undergo groin surgery and is facing months out

“We are looking for a level but clubs don’t want to sell. It is difficult. You think it is so easy.”

Teenager Cameron Borthwick-Jackson replaced Young at Anfield last Sunday and fellow rookie Guillermo Varela has also broken into the first-team set-up in recent months but Van Gaal is wary on asking too much of the youngsters.

“They have done great but the level of Manchester United is so high,” explained the manager. “To give every week a high performance normally is very difficult for youngsters to deliver that”.