Arsenal defender Bacary Sagna will miss the next three weeks after sustaining a hamstring injury during Tuesday's Champions League win over Napoli.
The France international full-back completed the full 90 minutes of the 2-0 win, but will be out of action until the end of October. Carl Jenkinson is set to deputise in the vacant full-back berth, starting with Sunday's trip to West Bromwich Albion.
“It is a blow [to lose Sagna] because he is a very complete defender,” Arsenal manager Arsene Wenger told his prematch media conference. “He is good in the air, can attack and he is a winner.
"For us it’s a handicap, but Jenkinson is growing as a player and I’m sure he will do very well.”
Wenger has insisted there "more to come" from his Premier League leaders, despite their flying start to the season.
The win over Napoli was hailed as one of the finest Arsenal performances in many a year, but Wenger is keen to play down rising expectations ahead of his side’s trip to The Hawthorns.
“I believe we can do better," he said. "Thre is more to come from us. It depends now on how much we want it. How hungry we are to continue to improve.
“It is still very early. We have played just six games and there are still 32 games to go. Maybe [Manchester] United have not had the expected start, but Chelsea are not far and we have only played six games. Chelsea had a tough schedule -- they had United away, they had Tottenham and you have to put that into perspective.
“Of course it is important for us to maintain our consistent run. We have had quite a good consistent run since March.”
Arsenal would record a Premier League club record ninth away win in succession with a win on Sunday, but Wenger is expecting a strong challenge from opponents who recorded an impressive 2-1 victory against Manchester United at Old Trafford last weekend.
“Basically we don’t look too much [if a match] is it away or at home,” he said. “We play with the same desire and the same attitude and as well we have a level of confidence that is there.
“West Brom represents a good test for us because they are on the back of an outstanding result at Manchester United. Their confidence level is certainly high as well, so it is a very interesting test. They have a big squad and it’s very difficult to predict who will play against us.”