Manchester United saw Marcus Rashford limp out of their 2-0 derby victory over Manchester City on Sunday.
The forward was replaced by Mason Greenwood midway through the second half, having turned in an industrious performance at the Etihad Stadium.
His absence, however, did not prevent the visiting side springing a shock victory over their neighbours.
With 69 minutes on the clock, Rashford went down in the Manchester City half and quickly signalled his need for assistance.
After some brief attention from the physio on his left ankle, he was forced to be replaced.
Although he was able to make his own way off the field, he was visibly limping and United will fear that he faces the prospect of missing several matches.
What matches may Rashford miss?
With the nature of Rashford’s injury yet to be assessed or discussed, it is unclear how many fixtures he will miss.
He must, however, be classed as a major doubt to play Milan in the Europa League on Thursday and also West Ham at Old Trafford in the Premier League next weekend.
Before the end of the month, Man Utd also have the return leg against the Rossoneri to play as well as an FA Cup quarter-final against Leicester.
The international break, however, means that they only have one Premier League match to play before they tackle Brighton at Old Trafford on April 3, limiting the impact his problem is likely to have on their quest to finish second in the top flight.