Schurrle spoke often with Ballack about life at Stamford Bridge.
"We talked a lot about it," Schurrle said.
"I have a lot of contact with him, we send each other SMS messages regularly, so I spoke to him and he told me I had to make the move because Chelsea is a great club with great fans and great staff.
"Throughout my whole career Michael's been a big help to me, he's always there for me to offer advice and tell me what I can do better.
"At this club, a place where he played so well, it's really helpful for me."