Ozil has been snubbed by Gunners boss Mikel Arteta with the midfielder left out of Arsenal’s Premier League and Europa League squads.
It has led to more questions over Ozil’s Emirates future with his contract in north London due to expire next summer.
And former Arsenal captain Koscielny has now given his views on Ozil and what the future holds for the German international.
"We’re both part of the 'Arsene Wenger Generation’,” Koscielny told French outlet L'Equipe . "The coach loved him as a player. It was more complicated with Unai Emery and Mikel Arteta.
"Knowing him, he must always be professional in training, always on time. He is undoubtedly at the level demanded by the Premier League.
"There is probably a certain case with the club since last year, I hope both sides find a deal that works for everyone.
“He is a competitor. I hope to see him back on the pitch soon, at Arsenal or elsewhere, because he is real talent.
"As a man, he’s a very good person, who got along with all his teammates. He gave a lot, helped sick children. He is a generous person, with whom I got along very well.
"As a player, he is in my opinion a phenomenon. He can find passes that no one sees, he’s a maestro. He can rock a game with incredible passes."
Ozil’s agent has blasted Arteta’s decision, with Dr. Erkut Sogut saying: "Arsenal fans deserve an honest explanation, not [Arteta] saying 'I failed Ozil'.
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“You didn't fail Ozil: you failed to be fair, honest and transparent and treat someone with respect who has a contract and was loyal all the time.
"Every single person outside knows he hasn't treated him fairly. He didn't give him a chance to show himself this season.
“If he is still under contract, the player should have the option to stay and fight for his place. Mesut hasn't been given that.”