Louis van Gaal
Van Gaal says the club are now in desperate need of another option at full-back Getty

Manchester United manager Louis van Gaal says the club are actively looking to sign a full-back but is unsure whether the club can find the right player during the January transfer window.

Speaking at a press conference ahead of the Premier League clash with Southampton on 23 January, Van Gaal confirmed Ashley Young is facing a lengthy spell on the sidelines after suffering a "severe" groin injury that requires surgery.

The 30-year-old, who has been deployed at both left and right-back this season, joins Luke Shaw, Antonio Valencia and Marcos Rojo on the club's injury list, a further blow to United's already depleted options at the back.

Van Gaal has turned to young full-backs Cameron Borthwick-Jackson and Guillermo Varela this season when he has been without more senior options but insists he needs more options.

"I have started with Valencia, Shaw, Rojo, Darmian and Young, sometimes, and they are all injured – only Darmian is now back," Van Gaal said, United's official website reports. "So, I need full-backs and you have seen how I have used youngsters like Borthwick-Jackson and Varela, who are doing great, but the level of Manchester United is high."

Both Borthwick-Jackson and Varela were thrown into the deep end on their full debuts in a crucial Champions League tie against Wolfsburg, providing encouraging performances despite United crashing out of the competition on that night.

Borthwick-Jackson was brought into another high-profile match off the bench against Liverpool at Anfield on 17 January but again impressed despite the high-pressure circumstances.

But Van Gaal is wary of too much expectation being placed on his young players and he is hopeful of bringing in a full-back who can alleviate the pressure on his squad.

"To give a high performance every week normally is very difficult for youngsters, which is why we have to look always in this transfer period for replacements. The difficulty is that we ask for a level and the clubs do not want to sell in this period and that is our problem. We are looking, but it is not so easy. Nobody can understand that because it is easy and it is not so."