Manchester United says winger Ashley Young is facing a lengthy time out with a groin injury which will require surgery. Young picked up the injury three minutes before halftime in the 1-0 victory at Anfield last week and was replaced by Cameron Borthwick-Jackson, who has made three appearances for United this season. United manager Louis van Gaal says "I think when you see how unlucky we have been in the fullback position, only (Matteo) Darmian is now back. So, I need fullbacks and you have seen how I have used youngsters like Borthwick-Jackson and (Guillermo) Varela, who are doing great but the level of Manchester United is high."