Manchester United and England winger Ashley Young faces "a long time" out with a serious groin injury, manager Louis van Gaal has confirmed.
The 30-year-old, who needs an operation, was injured in last Sunday's 1-0 win over Liverpool at Anfield.
Young, who joined United from Aston Villa on a five-year deal in 2011, has made 23 appearances this season.
He has won 30 full England caps but has not featured for the national team since September 2013.
Young, who signed a new deal last summer that ties him to Old Trafford until at least 2018, has been one of United's most impressive players this season despite often filling in at full-back.
His absence adds to a list of injuries in wide positions, prompting Van Gaal, whose side host Southampton on Saturday, to admit that he is looking to bring in new signings.
England left-back Luke Shaw suffered a double fracture of his right leg in September, defender Marcos Rojo has had shoulder surgery and winger Antonio Valencia is a long-term casualty with a foot problem.
Full-backs Guillermo Varela, 22, and Cameron Borthwick-Jackson, 18, both made their first Premier League starts in the defeat at Bournemouth last month.
"I need full-backs," said Van Gaal. "I have used youngsters a lot of times. Borthwick-Jackson and Varela are doing great, but the level at Manchester United is high.
"It is very difficult for youngsters to do that every week. That is why we have to look for reinforcements. We are looking but the clubs don't want to sell. Everybody thinks it is easy, but it is not so."
'The pressure is a little bit gone'
His position has not been helped by speculation United are interested in Pep Guardiola, who is leaving Bayern Munich at the end of the season, and former Chelsea manager Jose Mourinho, who is without a club.
"I don't think the press have to help me with my decisions," Van Gaal said. "First they have sacked me, now they are interfering with my future. I don't have to answer."
Asked whether he was feeling any easier after a five-match unbeaten run, the 64-year-old Dutchman added: "The pressure is a little bit gone.
"We have to win. Our fans expect us to win, especially at home."