Ozil got injured in a London derby versus Chelsea on Oct. 5, which Arsenal lost 2-0.
In comments made to the British press Thursday, Ozil said his treatment was taking more time than expected.
"I have already been out for five weeks and will be out for another seven weeks," he said. "That is a really long time, but that is the way it is in football sometimes. My head is held high and we look forward."
The North London club has been battling with injuried players, including goalkeeper David Ospina, defenders Laurent Koscielny and Mathieu Debuchy.
The knee injury has forced "Gunners" key player Ozil to miss the upcoming UEFA Champions League Group D match against Galatasaray on Dec. 9 in Istanbul.
In Group D, Arsenal are at runners-up position with seven points with two games to spare. The club is in the sixth place with 17 points as of Match Day 11 in the English Premier League, which Chelsea top with 29 points.
