Arsenal midfielder Abou Diaby faces a number of weeks on the sidelines after limping off against Wigan.
The 24-year-old France international suffered a calf injury in the first half of the Latics clash on Wednesday evening, and his side went on to draw 2-2 at the DW Stadium.
Diaby had appeared as a substitute against Chelsea in the Gunners' previous game but was thrown into the starting line-up by Arsene Wenger against Wigan.
Wenger told the club's official website: "It is a calf strain. He is out for a while now. Some weeks I think."
Diaby has only made nine appearances for Arsenal this season and recently missed nine weeks with an ankle knock.
Wenger made eight changes to his side for the game at Wigan but paid the price as Sebastien Squillaci netted a late own goal to leave the tie in a stalemate.
The Gunners have the chance to get back to winning ways when they take on Birmingham on New Year's Day.
