The German has had issues with coaches in the past over the manner in which he applies himself in training.
Arsene Wenger, Unai Emery and Freddie Ljungberg all had problems with the World Cup winner over attitude.
And Mikel Arteta is the latest - though the Spaniard has taken a much more hard stance.
With one year remaining on his contract, Ozil was told in the summer his services were not required.
It led to him not being named in either the Premier League 25-man squad or the Europa League one.
As the Gunners count down the months until the former Real Madrid star leaves, it would be easy to dismiss his efforts in training.
But Mustafi has insisted it has been the opposite and that his compatriot has been exemplary.
He said: "I can’t say too much about it. They have been talking a lot about it.
"For me, Mesut is not just a team-mate, he’s a friend. I respect him and he has always respected me and everyone else as far as I have seen.
"He will always have my respect and I will always be there for him if he needs something to motivate and push him.
"But at the moment every time I see him in training he’s doing the best he can.
"He tries to train well and everything else is not in my hands. I’m not the one who makes the decisions."
It remains to be seen where Ozil will end up next season with his time in north London coming to a close.
Turkish clubs Fenerbahce and Galatasaray are leading the charge for the £350,000-a-week star.
Mustafi added: "Of course if you are not in the squad you are going to be disappointed and even him, I think the last thing you want to see is something being left out and not being disappointed.
"This would be the wrong thing. Of course, he was disappointed but he’s experienced enough to deal with the situation.
"But for me, it’s about how I see him on the training pitch and I can say nothing negative about him."