The former Germany international seems determined to try his luck abroad once again and says that all was not well when he returned to the club in 2010
The 35-year-old has been strongly linked with pastures new in the summer, when his contract with the Bundesliga outfit expires.
"Nothing has been decided yet," Ballack told Sky Sport Germany. "However, I want a new challenge which is likely to be abroad."
In January, Ballack's agent declared that his client could go to "China, Arabia or the United States" next.
The former Germany international spent four years at Chelsea before moving back to Leverkusen in 2010, where he had played between 1999 and 2002.
He revealed that upon returning to the BayArena, there were some internal problems regarding his squad role.
"I had other offers when I decided to return," Ballack explained. "It was a matter of love. I think there were internal communication problems in terms of my role in the team. [Then-coach] Jupp Heynckes began increasingly to use younger players and [sporting director Rudi] Voller wanted me to play anyway."