Arsenal's Ozil to miss Spurs derby - Wenger
Arsenal's German midfielder Mesut Ozil (C) during a training session at Arsenal's training ground at London Colney, north of London, on March 10, 2014 - by Glyn Kirk
The German international sustained the problem during his side's 1-1 draw at Bayern Munich on Tuesday, which saw Arsenal eliminated from the Champions League in the round of 16.
Ahead of Sunday's north london derby at White Hart Lane, Wenger told the club website: "He's out. I don't know for how long, but it is a hamstring injury. There are scans going on."
Wenger also revealed that Welsh midfielder Aaron Ramsey has suffered a setback in his recovery from a thigh injury that has kept him on the sidelines since December.
"We have had to defer his comeback to full training, so he is not available," Wenger said. "He is having difficulties in the final stages of his rehab. It looks to be short-term."
Wenger is already without Theo Walcott and Jack Wilshere due to injury, but says that Swedish loan signing Kim Kallstrom could make his debut at Tottenham after overcoming a back problem.
"Kallstrom joins the normal training group today (Thursday) and (striker Yaya) Sanogo too," he added.
"I will have to decide if Kallstrom is OK to be in the squad on Sunday. I will see how he looks. It is not impossible."