Arsenal goalkeeper Bernd Leno left their game against Brighton and Hove Albion on a stretcher with what looked to be a serious knee injury.
In the 36th minute of a goalless first half at the Amex Stadium on Saturday, Leno dashed to the left-hand edge of his penalty area to claim the ball and was fouled by Neal Maupay while doing so.
When landing, the Germany international's right knee appeared to buckle and he audibly yelped in pain as the medical staff rushed towards him.
Leno received lengthy treatment before making his displeasure towards Maupay clear as he was carried off.
Emiliano Martinez entered the fray for Arsenal, who have been beset by injury problems since the Premier League restart.
Midfielder Granit Xhaka and defender Pablo Mari sustained ankle damage during Wednesday's 3-0 defeat at Manchester City, with the latter facing a long spell on the sidelines.