Nike said it would continue to support what it termed the “Livestrong initiatives,” though it did not say how. What is clear is that Armstrong’s value to the world’s largest sporting goods company has diminished. Armstrong, who retired from competitive cycling last year, was stripped of his seven Tour titles when he chose not to contest the Usada doping accusations. He has also been barred for life from competing or having any official role with any Olympic sport or other sport that follows the World Anti-Doping Code. As a result, he was less likely to help Nike sell its co-branded hoodies, shoes and Dri-Fit workout gear.

“The cynical side of me says that they are not making any money off of him and the evidence has piled up so there’s no point in sticking with him,” said Bob Dorfman, who analyzes athlete endorsements at Baker Street Advertising in San Francisco.

Nike stood by Woods and Bryant, Dorfman said, because their controversies were off the field and not directly linked to their performance. Nike cut its ties to Michael Vick, who was convicted of participating in a dogfighting ring, but re-signed him after he returned to the N.F.L.

The allegations against Armstrong undermined his success as a cyclist and prompted a small group to protest outside Nike’s headquarters Tuesday. In recent years, Nike stopped sponsoring Marion Jones and Justin Gatlin, two sprinters entangled in doping scandals.

“When you look at these relationships, the primary factor you choose an endorser for is their performance,” said Jim Andrews, senior vice president at IEG, a sponsorship consultant. “The primary benefit Tiger brings to Nike is his performance as a golfer. When he had his indiscretions, you could decide that he was still going to perform and excuse the character issue. With Lance, you don’t have that avenue because everything he did as a cyclist has been discredited.”

To an unusual degree, Armstrong transcended his racing career because of his well-publicized battle with testicular cancer. He not only survived the disease but also went on to win the Tour, a grueling three-week race. His accomplishments prompted millions of people to buy and wear yellow Livestrong wristbands.