The German midfielder admitted he is looking to find pastures new after two years at the BayArena and a spell in the United States is a very strong possibility
The 35-year-old is widely expected to leave Leverkusen in the summer, when his contract with the Bundesliga outfit expires.
A move to the United States has been suggested as the likeliest scenario for Ballack, whose agent revealed last month that the former Germany international was interested in joining the New York Red Bulls.
"The fire is still burning, I am still looking for a challenge," Ballack told ZDF.
"There were talks with Major League Soccer, I am leaning towards a move there. A decision will not be made until after the season."
Ballack, who returned to Leverkusen in 2010, has made 23 competitive appearances this season for the BayArena outfit.