The head of cycling's governing body has been replaced on a key International Olympic Committee panel after the Lance Armstrong doping scandal.
Pat McQuaid, the president of the International Cycling Union, said he was too busy to attend all the meetings of the Olympic commission evaluating bids for the 2020 Summer Games.
"It's quite simple," McQuaid said.
"I have too much going on and I can't afford to be spending two weeks away from the office in March."
The panel is assessing the 2020 bids from Madrid, Tokyo and Istanbul, and is due to pay four-day visits to each of the bidding cities in March ahead of a detailed report this summer.
The IOC will choose the host city Sept. 7 in Buenos Aires.
McQuaid was appointed to the 10-person commission in September as the representative of the Association of Summer Olympic International Federations, but has now been replaced by Patrick Baumann, a Swiss IOC member and secretary general of international basketball federation FIBA.
"He couldn't meet the schedule and we had to find someone else," said IOC vice president Craig Reedie, who chairs the commission.
"That's all. There's nothing sensitive about it in any way."
McQuade has already lost his sports on the World Anti-Doping Agency executive committee and foundation board, being replaced by Turkey's Ugur Erdener last year.
The UCI president, and predecessor Hein Verbruggen, have come under scrutiny after the US Anti-Doping Agency report that detailed systematic doping by Armstrong and his teams. Armstrong has been stripped of his seven Tour de France titles and banned from sports for life.
Cycling's governing body has since set up an independent commission to investigate the doping scandal and the federation's links with Armstrong. McQuaid and Verbruggen are expected to meet the three-member commission during its scheduled hearing in London this April.