Ballack, now 36, spent four years with Chelsea between 2006 and 2010, and is excited to see the return of the man who signed him.
"I was not completely surprised to see Jose Mourinho back because I read in the papers a lot about him going there," he told chelseafc.com. "He is smart enough to know things always change when you go back to a club you were at before. He has a fantastic reputation and they love him at Chelsea, but also in England, even if he may divide opinion among other supporters and media.
"He had great success since he left Chelsea, winning the Champions League and I am sure he will be trying this again with Chelsea. I wish him all the best. We have a good relationship, he also came to my testimonial game and I believe he is really, really committed to the job, otherwise he may take time out after such an intense position as Real Madrid. That means he is still hungry and motivated. That's good for Chelsea."