Manchester United defender Marcos Rojo has joined the club's lengthy injury list.
The Argentine, 24, was replaced by Phil Jones for Sunday's home game against Liverpool after picking up an injury in training.
Fellow defenders Chris Smalling, Luke Shaw and Rafael are already sidelined.
Speaking after the victory over Liverpool, manager Louis van Gaal refused to reveal the nature or extent of Rojo's injury.
"It happened yesterday so we will have to wait and see," said Van Gaal. "I don't think it's healthy but I am not a doctor."
Possibly referring to an incident in November when the club initially tweeted that Daley Blind would be sidelined for six months rather than several weeks, Van Gaal added: "Two or three weeks ago there was a misunderstanding here so it's better to say nothing about the injury."
United's record signing Angel Di Maria, Daley Blind and Jesse Lingard were also unavailable for Sunday's Premier League game because of injury.