The German international suffered a muscle injury in the second minute of the Champions League clash with Bayern Munich nine days ago.
The Gunners look set to be without their record signing for up to three weeks. Ozil has only missed four of Arsenal's Premier League games since joining from Real Madrid in September.
But Flamini believes Arsene Wenger will find a way to cope without the Premier League's player with the fourth most assists.
Flamini told the Daily Mirror:
"He is one of my closest team-mates, he has outstanding quality and has brought so much to the club on the pitch and off the pitch.
"In the dressing room, he is a very important player. Every time on the pitch he gives so much.
"I'm very proud of him, very happy to have him in our team.
"He’s a player of great quality. We will miss him a lot over the coming weeks but I think the manager will find a way to replace him, even if it won’t be easy as he’s such a talented player."Arsenal travel to Stamford Bridge on Saturday to face league leaders Chelsea in Arsene Wenger's 1,000 game in charge of the north London club.