Ole Gunnar Solskjaer has revealed he is not sure how long Anthony Martial will be out for after the Manchester United forward suffered an injury in training.
Martial has scored 15 goals in all competitions this season, with three of those coming in United's past three matches.
However, the 24-year-old was not included in Solskjaer's side to face Club Brugge – against whom Martial netted in a 1-1 away draw last week – in the second leg of United's Europa League last-32 tie at Old Trafford on Thursday.
January loan signing Odion Ighalo instead came in for his full debut.
Solskjaer subsequently confirmed Martial had sustained an injury during a training session on Wednesday, and United's manager was unsure of the severity of the Frenchman's issue.
"He didn't feel right after the training yesterday or [rather] he walked off during training and he's injured," Solskjaer told MUTV.
"So, hopefully it won't be too bad, but I don't really know yet how long he'll be out."
Martial's form has coincided with an upturn in results for United, who sit fifth in the Premier League and visit Everton on Sunday.
The club are still without Paul Pogba, whose future remains in doubt, and Marcus Rashford.