Louis van Gaal has confirmed that Angel di Maria is facing a spell on the sidelines with the hamstring injury that forced him off during Manchester United's 3-0 win over Hull City.
The Argentine departed the game at Old Trafford after just 13 minutes after pulling up unchallenged against the Tigers. The £59.7 million summer signing was replaced by Ander Herrera, who ended up playing a key role in the victory.
Van Gaal has now confirmed that the injury is set to keep him out of Tuesday's game against Stoke City, but does not know how long he will be out.
"I think Di Maria was hamstring," the United boss told reporters.
"He knows his own body very well because at once he said he had to come off, so maybe it is not too bad.
"It is always difficult to say. We will have to wait and see. He shall be out for the match against Stoke for sure."
Di Maria becomes Manchester United's 41st separate injury of the current season and comes as a significant blow to Van Gaal ahead of another crucial game against the Potters.
The 26-year-old joins Luke Shaw, Daley Blind and Phil Jones on the sidelines while Jonny Evans is closing in on a return after playing for Manchester United's U21 team last week.
Van Gaal welcomed Marcos Rojo back into the team following a dislocated shoulder and Radamel Falcao appeared off the substitutes bench following a calf injury.
The Dutchman will now be nervously waiting scan results for Di Maria with injured hamstring ranging widely in severity. A mild strain could keep him out for no more than a week while a Grade III tear could sideline him for the rest of the year.