Francis Coquelin's injury is not as bad as initially feared, but the Frenchman will not be ready for Arsenal's trip to Burnley on Sunday.
Coquelin suffered a knee injury in the 3-0 win over Chelsea last weekend and was expected to be out of action for at least three weeks.
But Gunners boss Arsene Wenger is now working to a shorter timeframe.
"Coquelin is looking much better," he said at a media conference.
"The ligament is not as damaged as we thought, but we have to be careful. He will still not be ready for the game against Burnley.
"[Olivier] Giroud will be out.
"[Aaron] Ramsey will be available after the international break."
Arsenal have been in sublime form in recent weeks and Wenger is hopeful they can build on their recent wins against Chelsea and Basel when they take on the Clarets.
"We want to continue our good form and please the fans," Wenger continued.
"It looks like we have moved forward. The team believes in what we are doing. But we have to stay focused.
"We must have the same commitment against Burnley as in recent games. They showed against Liverpool and Watford what they can do. They are very dangerous on set-pieces and counter-attacks."