Arsenal manager Arsene Wenger says midfielder Alex Oxlade-Chamberlain will continue to be assessed after suffering a hamstring injury against Manchester United.
The youngster joins a number of other players on the sidelines although midfielders Jack Wilshere and Mathieu Flamini are expected to be back in the squad next week.
"[Alex Oxlade] Chamberlain has a hamstring strain, the only thing we don't know is how bad it is because usually the scans are only done 48 hours after the accident. That will be done today [Wednesday]," Wenger told the club's official website.
"Jack [Wilshere] is progressing well, he is not back in training yet.
"Mathieu [Flamini] is training, he could be available for the squad on Saturday.
"Gabriel may be [available] next week, he should come back into training on Sunday or Monday.
"I will have to test medically, physically, how the players are on Friday, and I will make my decision then. The big priority is of course West Ham."
