Arsene Wenger has confirmed that Theo Walcott, Laurent Koscielny and Gervinho will all miss the Champions League fixture against Olympiakos tomorrow evening.
England winger Walcott injured his knee during the 3-0 victory over Bolton Wanderers on Saturday afternoon and missed this morning's training session as a result.
Centre-back Laurent Koscielny suffered an ankle injury in the same game following a challenge by Wanderers midfielder Nigel Reo-Coker.
Ivorian Gervinho is currently suffering from a muscular problem and will not be risked at the Emirates Stadium.
Wenger did reveal that they could all return for Sunday's derby against Tottenham Hotspur.