Manchester United defender Raphael Varane is set to be out for about a month with a hamstring injury.
Varane suffered the injury in Tuesday's Champions League draw at Atalanta and was substituted in the first half.
The 28-year-old France international, who joined United for £34m from Real Madrid in August, had only just returned from a groin problem.
He will now miss crucial Premier League games against Manchester City and Chelsea.
Fellow centre-back Victor Lindelof missed the trip to Atalanta, leaving United manager Ole Gunnar Solskjaer facing a defensive headache for the visit of neighbours Manchester City on Saturday given skipper Harry Maguire has struggled for his best form and Phil Jones has not been involved in a first-team game for almost two years.