Swiss cyclist Oscar Camenzind will not compete in the Olympics after testing positive for the banned performance-enhancing drug, EPO.
His Phonak cycling team has also suspended the former world champion with immediate effect.
The Swiss Olympic Association said on Monday that traces of the drug were found in Camenzind’s urine when he was tested after a routine training session last month.
“We told Camenzind about the result of our test on Monday. He now has five days to ask for a follow-up test,” Oliver Hintz, head of the association’s anti-doping commission, told swissinfo.
But on Tuesday Camenzind confirmed he would not be seeking a second test and announced his retirement from the sport.
"I have made a big mistake and now I am paying the price," he said at a press conference in Lucerne.
"I took EPO five days before... I was tested. I injected it myself. I know that there is no excuse, but I would still like to take this opportunity to apologise to my team, my fans and my family," he added.
Under new regulations drawn up by Switzerland’s cycling association, a rider is automatically suspended from competitions if he tests positive for a performance-enhancing drug.
The rules state that there is no need to wait for the result of a second test.
Hintz said the positive test was the result of “thorough work” by anti-doping experts in Switzerland.
“This is a warning shot. I hope it will have wider consequences. But that’s not enough. The sporting associations have to step in to help change the conditions in competitive sports,” Hintz added.
The Swiss Olympic Association has nominated 24-year-old Gregory Rast to replace the 32-year-old Camenzind.
Camenzind had been expected to lead the Swiss cycling team during the road race competition in Athens, where the Olympic Games are due to get underway on Friday.
But Swiss expert Pierre-Henri Bonvin said Camenzind’s ban was unlikely to have much of an impact on the overall performance of the country’s cycling team.
“He had little chance of winning a medal,” Bonvin told swissinfo.
The Camenzind case is the biggest doping scandal in Swiss cycling since Alex Zülle, Laurent Dufaux and Armin Meier were suspended for seven months in 1998 after admitting that they had taken performance-enhancing drugs.
Camenzind has been suspended from his cycling team, Phonak, with immediate effect.
“We have nothing to do with Camenzind’s doping,” said team manager Urs Freuler.
"Every cyclist who tests positive in a race or during training... must expect to be dismissed immediately," he added.
32-year-old Oscar Camenzind has been a professional cyclist since 1996.
He was a member of Panaria, Mapei and Lampre before he joined the Phonak cycling team in 2002.
He was world champion in 1998, won the Tour of Lombardy (1998), the Tour de Suisse (2000) and the one-day Liège-Bastogne-Liège race (2001).
Swiss cyclist Oscar Camenzind has tested positive for the performance-enhancing drug, EPO.
His Phonak cycling team has suspended him with immediate effect.
On Tuesday, Camenzind admitted he had taken the drug and announced he was retiring from competitive sports.