Arsenal manager Arsene Wenger has confirmed that Aaron Ramsey is likely to be on the sidelines for three to four weeks with a hamstring injury.
The Wales international pulled up during the Gunners' 1-1 draw with North London rivals Tottenham Hotspur last weekend.
While some reports have claimed that the midfielder could be out of action for six weeks, Wenger has revealed that one month is more likely.
The Frenchman told reporters in this morning's press conference: "I've been told he could be out for three to four weeks, so I count four."
Arsenal will take on Chelsea at Stamford Bridge on Sunday.