Arsenal manager Arsene Wenger is expected to be without Aaron Ramsey for Saturday's Premier League crunch match with Chelsea at Stamford Bridge.
Ramsey was forced off in the first half of his side's shock 2-1 home defeat to Watford on Tuesday night, with Wenger confirming after the match that he has suffered a calf strain.
The full extent of the 26-year-old's injury remains uncertain, but he is unlikely to have recovered in time for Saturday's London derby against the Premier League leaders.
Arsenal will go into the match knowing that defeat would leave them 12 points adrift of Chelsea, all but ending their slim hopes of a title challenge this season.
Ramsey, who missed 13 games at the start of the campaign with a hamstring injury, is the latest midfielder to be ruled out for the Gunners, with Granit Xhaka suspended, Mohamed Elneny at the Africa Cup of Nations, Santi Cazorla still injured and Jack Wilshere on loan at Bournemouth.
Wenger himself will be forced to watch on from the stands as he serves the third of his four-game touchline ban.
