Australian sports scientist Stephen Dank is suing the Cronulla Sharks for defamation over claims that he "injected players with horse drugs", reports said.
Dank's lawyers filed a claim against the National Rugby League club in the New South Wales Supreme Court, Sydney's Daily Telegraph and other media said.
It alleges ex-club chairman Damien Irvine made defamatory comments about Dank "to the effect that he injected Sharks players with horse drugs".
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
The court confirmed the documents were lodged on Tuesday but said they would not be made public until the defence was filed, a process which could take a month or more.
Dank's solicitor Raed Rahal said in a statement he would be alleging that the Sharks club was "legally responsible" for Irvine's words, the Telegraph said.
Irvine stepped down after making the comments, saying Cronulla had been under intense pressure since being mentioned in a wide-ranging Australian Crime Commission (ACC) report into doping in sport.
The Australian Sports Anti-Doping Authority is investigating the club after the ACC report found the use of prohibited substances was common across multiple sporting codes, identifying six NRL clubs in total.
As many as 14 Sharks players have reportedly been accused of using prohibited drugs, with allegations they were given Thymosin Beta 4 -- a substance used on horses to increase muscle growth -- and CJC-1295 peptides in 2011.
Dank, who no longer works with Cronulla, has denied any wrongdoing.
"I have done nothing illegal with any club in the NRL," he told News Limited newspapers.
"All this upsets me deeply because it is not true. I am not a doping scientist or a cheat."
