Arsene Wenger admits he would like to strengthen his Arsenal squad defensively before the end of the transfer window.
New defensive signing Calum Chambers has made a positive impression in his first appearances for his new club, but Wenger is wary of demanding too much too soon from the £16m summer signing while Mikel Arteta sustained an injury against Besiktas in midweek.
Wenger said: "At the moment, we are not in an emergency case. We have the players we want but we are open as well to any opportunity until the end of the transfer window to strengthen our defensive department in quality and number.
"I share the assessment on Calum Chambers; he has done extremely well but I think as well in England you have to be a bit more patient.
"He has played three games and I believe it is important for the development of the players that he does not go too fast, not so much on the football front but psychologically as well.
"Players need to cross hurdle after hurdle stronger and it doesn't go too quick for them. For me that is something that is very important in development.
"We have just Mikel Arteta who is for sure out for the Everton game. Everybody else we have to check this morning, but we have no major problem apart from Mikel.
"He had a scan yesterday afternoon. I haven't got the result. I have a meeting to check about that. I don't know how long he will be out for.
"We will be a bit short of course. If it is a long-term injury, that puts us in a position where we have to be creative."
Per Mertesacker, Mesut Ozil and Lukas Podolski have been on extended leave since their World Cup success but they will be in contention this weekend.
Wenger said: "I will check today and tomorrow to see if they are ready for selection this weekend.
"This is the target that I set them to ensure that they were ready for selection against Everton. Will I use the three? Certainly not, because they lack competition but they might be included in the squad for Saturday."