The International Cycling Union, which chose not to appeal the USADA's lifetime ban, stripped Armstrong of his record seven Tour victories.
The World Anti-Doping Agency also agreed with the sanctions, which means Armstrong may not compete in sports governed by that agency's code.
Before the ban, he was competing in Ironman triathlons and had won two of the five events he had entered.
Since the ban he has entered two non-sanctioned events.
So, why would Armstrong choose to make a confession now?
"I would suspect that he sees this as certainly his best way forward," Snell says. "He would have taken strong legal advice, of course. When you look at the kind of stuff that Oprah's done over the years, it's a chance to get ... heartfelt emotions across."
The New York Times has reported that Armstrong was contemplating publicly admitting he used illegal performance-enhancing drugs. Such an admission might lead toward Armstrong regaining his eligibility.
One of his attorneys denied Armstrong was in discussion with the two anti-doping agencies.
Herman, in a recent e-mail to CNN Sports, did not address whether Armstrong told associates -- as reported by the newspaper -- that he was considering an admission.
But such an admission could open him up to lawsuits, something Armstrong is likely well aware of.
"He is surrounded by the best legal advice, the best legal team," Snell says. "It's very hard for anyone to imagine him going into this without having been fully briefed, made aware of absolutely every scenario."
In the past, Armstrong has argued that he took more than 500 drug tests and never failed.
In its 202-page report that detailed Armstrong's alleged use of performance-enhancing drugs and blood transfusions, the USADA said it had tested Armstrong less than 60 times and the International Cycling Union conducted about 215 tests.
The agency did not say that Armstrong ever failed a test, but his former teammates testified as to how they beat tests or avoided the tests altogether.
The New York Times, citing unnamed associates and anti-doping officials, said Armstrong has been in discussions with USADA officials and hopes to meet with David Howman, chief of the World Anti-Doping Agency. The newspaper said none of the people with knowledge of Armstrong's situation wanted to be identified because it would jeopardize their access to information on the matter.
Armstrong: The legend and the fall
Armstrong has been an icon for his cycling feats and celebrity, bringing more status to a sport wildly popular in some nations but lacking big-name recognition, big money and mass appeal in the United States.
He fought back from testicular cancer to win the Tour from 1999 to 2005. He raised millions via his Lance Armstrong Foundation to help cancer victims and survivors, an effort illustrated by trendy yellow "LiveSTRONG" wristbands that helped bring in the money.
But Armstrong has long been dogged by doping allegations, with compatriot Floyd Landis -- who was stripped of his 2006 Tour de France title after failing a drug test -- making a series of claims in 2011.
Armstrong sued the USADA last year to stop its investigation of him, arguing it did not have the right to prosecute him. But after a federal judge dismissed the case, Armstrong said he would no longer participate in the investigation.
In October 2012, Armstrong was stripped of his titles and banned from cycling. Weeks later, he stepped down from the board of his foundation, Livestrong.