Manchester United defender Lisandro Martínez has suffered a cruciate ligament injury, the club have confirmed.
Martínez was taken off on a stretcher during the second half of United's 2-0 defeat to Crystal Palace on Sunday.
The Argentina international will not play again this season and is likely to be out for more than six months.
A club statement issued on Thursday added: "Manchester United can confirm that Lisandro Martínez suffered an injury to his cruciate ligament in Sunday's game against Crystal Palace.
"Assessment of the injury is ongoing to determine the appropriate course of treatment and the timescale for his rehabilitation.
"Everyone at Manchester United wishes Lisandro Martínez strength for a successful recovery and we will be supporting him every step of the way."
Argentina's next games are World Cup qualifiers against Uruguay and Brazil in March. The Albiceleste are top of the standings for the CONMEBOL zone, five points clear of Uruguay.
"Licha [Martínez] is a difficult situation," Ruben Amorim told a news conference on Thursday. "He's going to be out for a while. We don't know the extent of the injury but it's going to take time."
Information from The Associated Press was used in this report.
