London - Arsenal's defensive troubles have deepened after Kieran Gibbs was ruled out for another month following surgery on his left groin.
The England left back has been out of action since October after having surgery to remove a hernia, but it had been hoped he would be back this week.
Defenders Johan Djourou, Andre Santos, Carl Jenkinson and Bacary Sagna are already out for the Gunners.
Those injuries have forced manager Arsene Wenger to field centre backs Thomas Vermaelen and Laurent Koscielny at fullback.
Looking ahead to the January transfer window, Wenger says he will sign a fullback "if there is a good opportunity."
Arsenal is fifth in the Premier League, 12 points behind leader Manchester City.