Arsenal are fearing the worst after Kieran Tierney returned from international duty with a suspected serious knee injury.
Left-back Tierney will have a scan on Tuesday to determine the severity of the setback and whether he will need surgery, amid concerns he could miss the rest of the season.
Tierney played in both of Scotland’s friendlies against Poland and Austria, completing the full game on each occasion.
But he reported the problem once he got back to his club and was absent for Monday’s trip to Crystal Palace, replaced by Nuno Tavares.