Ballack was a vastly experienced 29 years old when he arrived in England to play for Chelsea in 2006, compared to Ozil’s 25.
Ballack told the Daily Express: “When Ozil first arrived, he wanted the ball so much. But he is not used to playing through the winter without a break like you do in England. It can be hard to adapt.
“Its new for him. But he may need a while to come back into full shape. If you only lose 10 per cent it can really affect your performance.
“He is tired but the expectation is so high. He should be one of the leaders of the team.
“He cost so much and that also means pressure to perform week in and week out.
“That is what he is learning about. I am sure he will be a really big and important player for Arsenal in the future.”