Parramatta Eels' Michael Jennings has been provisionally suspended by the National Rugby League after failing a drugs test.
Jennings' A sample tested positive for performance-enhancing ligandrol and ibutamoren, and their metabolites, in September, said the league.
The centre, 32, says he is "completely shocked" and denies cheating.
Meanwhile, police have charged St George Illawarra Dragons' Tristan Sailor with aggravated sexual assault.
Playmaker Sailor, the 22-year-old son of former Australia dual-code star Wendell, is accused of attacking a woman at a home in Sydney last week, a New South Wales police statement said.
"The club is taking the matter very seriously and will continue to work with Tristan and all relevant authorities," the Dragons said.
Sailor was refused bail and is due to appear in court on Sunday.
Jennings could face a four-year ban if found guilty of taking the substances banned by the World Anti-Doping Agency, but can ask for his B sample to be analysed.
"I am totally against any form of cheating in sport and am completely shocked to find myself in this position," the Australian told News Corp.
"I have dedicated the last 14 years of my life to playing in the NRL. I would never do anything to jeopardise my standards, my reputation or the legacy I leave, especially for my son."
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