Diaby suffers new injury blow
"It is a calf strain," manager Arsene Wenger told the club's website after Diaby's latest injury blow. "He is out for a while now. Some weeks I think."
The French midfielder came on as a substitute in the 3-1 victory over Chelsea on Monday after missing nine weeks with an ankle injury and started against Wigan before hobbling off.
Wenger made eight changes to the side that beat Chelsea for the trip to Wigan which ended in a 2-2 draw, preventing the Gunners from moving level on points with Premier League leaders Manchester United and Manchester City.
They face another testing away trip to Birmingham City on New Year's Day.