"Despite this evidence and despite all the evidence that has come out, he's got a strong core of people who believe in him and will always believe in him because of his link to fighting cancer," said Strickland, who chronicled Armstrong's 2009 return to the Tour de France in a 2011 book.
But how Armstrong might move on is unclear.
"Certainly, he's not going to be able to move on within the sport," Strickland told CNN. "It seems likely that all of his Tour victories will be stripped. He won't be allowed to participate in any sports that are signatories of WADA, the World Anti-Doping Agency. But he's found a few triathlons to do in the meantime."
And he said the allegations could lead to the reopening of a criminal case against Armstrong that federal prosecutors closed without charges in February.
"What's next is years and years of fighting if the criminal case is reopened," Strickland said.
The USADA opened its own case, which does not carry criminal penalties, in June.