Arsene Wenger has admitted that he is looking to sign a defender after Per Mertesacker was ruled out of action until the end of the year.

The German centre-back suffered a knee injury during a pre-season friendly against Lens last week, which ended in a 1-1 draw.

"I don't count that Per will be back before the end of the year and I will miss him deeply, we have lost a heavyweight in our dressing room," Wenger told The Telegraph.

"I can understand the expectation level and anxiety level of our fans because they see other clubs bringing players in.

"The best way to conclude transfers is not to talk about it, but we are in the market. Do I think we will sign an experienced central defender before the season starts? Yes, I do."

Arsenal will step up their preparations for the new Premier League season with a friendly against Mexican team Chivas on Sunday.