Manchester United defender Lisandro Martinez is expected to be out for two to three months with a foot injury.
The 25-year-old Argentina international missed the end of last season after fracturing a metatarsal in April.
He returned to action at the start of this season but United say he will be side-lined again because of “an aggravation” to the injury.
The club said Martinez “experienced the setback in our Premier League game against Arsenal earlier this month”.
They added: “It has now been determined that he needs a period on the side lines for recovery and rehabilitation.
“Assessment is ongoing to determine next steps.”
At a news conference on Friday, manager Erik ten Hag said: “It is very sad, for him and the team, because he was not 100% fit.
“I think it was a big difference, the Licha Martinez in the last games and the Licha Martinez we have seen in the last season.”
Martinez faced Wolves, Tottenham and Nottingham Forest before playing in a 3-1 defeat at Arsenal on 3 September.
He went on to play in losses against Brighton and Bayern Munich but then missed wins against Burnley and Crystal Palace.
Martinez joined United from Ajax last July in a deal worth up to £57m and helped them finish third in the Premier League and win the Carabao Cup.
