The 29-year-old French international was stretchered off after clashing with Norwich midfielder Bradley Johnson in the 33rd minute of Saturday's 3-3 draw at the Emirates, and it was later confirmed he had suffered his second broken leg of the season.
"He will have surgery tonight," said manager Arsene Wenger on Thursday.
"It is a straight broken fibula. We expect him to be out for a few months but let's see how surgery goes."
|THREE AND EASY?
|4/6||Arsenal are 4/6 with bet365 to beat West Brom on Sunday.|
The right-back missed three months of the current campaign with an identical injury after falling awkwardly against Tottenham, but revealed at the weekend that he thought his latest setback had been caused deliberately by Johnson.
Arsenal travel to face West Brom on Sunday needing a victory to secure a third-placed finish and guaranteed entry to next season's Champions League. Wenger also admitted that winger Theo Walcott is a major doubt and will have a late fitness test on a hamstring injury to see if he can play a part.
"He will have a test. I don’t know yet if he will be included in the squad or not. It is possible," said the Frenchman.
"We have little doubts about [Ju Young] Park, [Sebastien] Squillaci and [Andre] Santos but they should all be ready."