Lukasz Fabianski faces more time on the sidelines after being ruled out for three weeks with a thigh injury.
The Arsenal goalkeeper made his first appearance of the season against Liverpool in the Carling Cup on Wednesday after overcoming knee surgery in the summer.
The Poland international appeared to be fine as he was walking off the pitch at the full-time whistle but Gunners boss Arsene Wenger has confirmed the shot-stopper picked up a problem with his thigh.
The situation leaves Wenger with a straight choice between Vito Mannone and Manuel Almunia for the North London derby against Tottenham at the weekend.
"We lost Lukasz Fabianski with a thigh injury," Wenger told the club's official website.
"He will be out for three weeks. Of course it is a big disappointment because he has just come back from injury.
"Also (Jack) Wilshere (ankle), Denilson (back) and (Tomas) Rosicky (knee) will not be back for the game at the weekend. But we did not lose any players from last night."