Arsenal boss Arsene Wenger admits he's unsure of when skipper William Gallas will be available.
Winger Alex Hleb, though, could return from a knee problem to face the Hammers.
"William Gallas is maybe a week or 10 days away, but I would not like to set a time on it really," said Wenger, whose side continue their Champions League campaign against Steaua Bucharest in Romania next week.
"As for Rosicky, you can probably fix the date for Sunderland [next Saturday]. Jens Lehmann will be another week."