Arsenal striker Eduardo aggravated a thigh muscle injury against Olympiacos in the Champions League on Tuesday.
"Unfortunately we lost Eduardo after he came on [against Olympiacos]," Arsene Wenger told Arsenal TV Online.
"It was a gamble to play him and unfortunately his muscle injury got worse. He will be out. It is the same thigh muscle and has recurred a few times now. But Walcott and Bendtner are available."
Manuel Almunia has been missing with a chest infection since the defeat at Manchester City on September 12 and may not be ready to return.
"Manuel Almunia is not far," said Wenger. "I will assess him Friday or Saturday but he looks unlikely to be ready."
