Arsenal striker Eduardo aggravated a thigh muscle injury against Olympiacos in the Champions League on Tuesday.
"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 is not far," said Wenger. "I will assess him Friday or Saturday but he looks unlikely to be ready."