SYDNEY (Reuters) - Former Olympic relay champion Kylie Palmer has pulled out of the Australia team for next month's swimming world championships in Russia after being informed she had failed a dope test at the 2013 edition of the event.
Palmer, a 4x200m freestyle relay champion at the 2008 Beijing Olympics and a silver medalist in the same event four years later in London, was informed earlier this year that a sample she gave had shown traces of a banned substance.
When the "B" sample she submitted in Barcelona two years ago also showed traces of the substance, Palmer accepted a provisional suspension until the case was heard by the doping tribunal of swimming's world governing body FINA.
"Kylie presently has no idea how the prohibited substance came into her system and is continuing to investigate the matter to the extent that she is able, given the passage of time," said a media release issued on her behalf by Swimming Australia.
"Kylie categorically denies knowingly taking any prohibited substance in Barcelona in July 2013 or at any time in her career.
"Kylie has always been a strong supporter of the anti-doping measures undertaken by FINA and has prided herself on being a successful clean swimmer."
Swimming Australia did not reveal the banned substance in question but said a "minute" quantity of the drug had been discovered in the sample.
That Swimming Australia was not informed about the failed test until April this year could be explained by the introduction at some major sporting championships of the re-analysis of frozen samples with more advanced tests.
Palmer, 25, won an individual and relay silver in the 200m freestyle at the 2011 world championships in Shanghai and followed that with another relay silver in Barcelona.
She was part of the team that stunned the American and Chinese favorites to win the 4x200m relay gold in a world record time at the Water Cube in Beijing.
If found guilty of an offense, she faces a two-year ban that would rule her out of a tilt at a third Olympic Games in Rio de Janeiro next year.
"With much regret, Kylie has chosen to withdraw from the Australian team for the upcoming swimming world championships in Russia in late July whilst she focuses on defending the FINA proceedings against her," the statement concluded.
"Kylie will pursue her dream to represent Australia at the 2016 Olympic Games in Rio once the FINA proceedings are dealt with."
Editing by Peter Rutherford