Four top U.S. cyclists -- all former teammates of Lance Armstrong -- removed their names from consideration for spots on the Olympic team before its announcement this week.
Levi Leipheimer, George Hincapie, Christian Vande Velde and David Zabriskie asked that they be taken out of the running for places on the road cycling team for the Summer Games, USA Cycling announced in a brief statement Saturday.
"USA Cycling will not speculate on the reasoning behind their requests and will not have further comment," the statement said. "Any questions related to their decision should be directed to the individual athletes."
The national governing body for cycling announced Friday the five riders who will compete in London: Taylor Phinney, Tejay van Garderen, Chris Horner, Timmy Duggan and Tyler Farrar.
Leipheimer is currently third overall at the Tour of Switzerland, which concludes Sunday, and was not available for comment. Hincapie is preparing for the Tour de France and was unavailable, while an official for Garmin-Barracuda -- Vande Velde and Zabriskie's professional team -- did not respond to a request for comment.
All four riders spent time on the U.S. Postal team with Armstrong, the seven-time Tour de France champion who is facing fresh doping allegations by the U.S. Anti-Doping Agency.
USADA has also accused Armstrong's former team manager, Johan Bruyneel, and other associates of being involved in a longstanding doping conspiracy that supplied the champion cyclist's teams.
Armstrong and Bruyneel have both denied the allegations.
According to USADA's June 12 letter announcing the charges, "numerous riders" from Bruyneel's teams will testify he gave them performance-enhancing drugs or encouraged them to use them.
USADA has kept the identity of those riders secret, so it remains unknown whether the four who removed their names from Olympic consideration are among them.
Leipheimer, the reigning Olympic bronze medalist, is arguably the biggest name missing from the roster released by USA Cycling on Friday. He was teammates with Armstrong on the U.S. Postal team from 2000-01, and rejoined Armstrong during his comeback from retirement.
He told VeloNews earlier this year that he wasn't counting on riding at the Olympics.
Hincapie recently announced his intention to retire after the season. The five-time Olympian is scheduled to ride in the Tour de France next month for the BMC Racing Team, and will likely ride the USA Pro Cycling Challenge in August before finishing his decorated career.
He was teammates with Armstrong during each of his seven Tour de France titles.
"The BMC Racing Team is currently in its (pre-determined) Tour de France quiet period, meaning team directors and riders who are not actively participating in a race are not available for interviews," team spokesman Sean Weide said in an email to The Associated Press.
Hincapie told the AP earlier this year that he would ride in the Olympics if asked.
"They're probably going to want me on the team. I'm not saying I should be, but I want to go if I deserve a spot," Hincapie said. "We'll see. It's not something I'm thinking about every day, but I'd love to go to a sixth Olympics."
Vande Velde was a member of the U.S. Postal team from 1998-03, while Zabriskie -- the seven-time and defending national time trial champion -- joined the team for the 2001-04 seasons.
USA Cycling CEO Steve Johnson and Jim Miller, its vice president of athletics, declined through a spokesperson to discuss the five-man team that was chosen for the London Games.
The timing of the Olympics is made awkward by the Tour de France, which concludes July 22 in Paris. The men's road race is six days later, with the time trial scheduled for Aug. 1.
Some riders have been forced to choose between riding in the Olympics or the Tour.
Phinney, a former track cycling star, was selected to compete in the Olympic time trial and road race. He'll be joined on the road by newly crowned national champion Duggan, up-and-coming rider van Garderen, the veteran Horner and sprint specialist Farrar.
"We have a strong team going to London with a solid combination of experience, leadership and young talented athletes who are all capable of standout performances," Miller said in a statement announcing the team. "Each member of the team is deserving, we're proud to welcome them as a part of Team USA and look forward to a promising Olympic Games."