The Tour "is the intention," Armstrong's spokesman Mark Higgins told The Associated Press, "but we've got some homework to do over there."
Added Bill Stapleton, Armstrong's lawyer and longtime confidant: "We're not going to try to win second place."
What team he'll ride with and in what other races he'll compete are undecided, Higgins said.
"I am happy to announce that after talking with my children, my family and my closest friends, I have decided to return to professional cycling in order to raise awareness of the global cancer burden," the 36-year-old Armstrong said in a statement released to The Associated Press. "This year alone, nearly eight million people will die of cancer worldwide. ... It's now time to address cancer on a global level."
In an exclusive interview with Vanity Fair, Armstrong told the magazine he's 100 percent sure he's going to compete in the Tour de France next summer. "I'm going back to professional cycling," he said in the story posted Tuesday on the magazine's Web site. "I'm going to try and win an eighth Tour de France."