The Portuguese is back as manager at Stamford Bridge after departing in 2007 and Ballack believes it will be a positive union.
"He is a great character and a great coach. Even at his age he has had unbelievable success.
"To go back to a club like this, it is never a bad decision. Chelsea are a fantastic club - they won the Champions League last year and this year the Europa League.
"The money will be right for him, the fans love him, he has a lot of English supporters, even if they don't support Chelsea.
"Altogether it is a great package for him."