The 24-year-old Odesnik was stopped by customs officers on Jan. 2 as he arrived in Australia ahead of the Brisbane International and Australian Open, and eight vials, each containing 6 milligrams of the performance-enhancing substance, were found in his baggage.

Odesnik, pleaded guilty in the Brisbane Magistrates Court to importing the hormone, the Australian Customs Service said in a statement late Friday. He was fined A$8,000 ($7,280) plus A$1,142.80 ($1,040) in court costs.

Tennis Australia declined comment Friday, referring questions about Odesnik to the International Tennis Federation.

The ITF said it had received notification that the Odesnik had pleaded guilty to possession HGH.

“The case has been referred to the tennis anti-doping program, and we don't have any further comment,” the ITF said in a statement to The Associated Press. “It's just like any other case that gets referred to the anti-doping program, we don't have a comment on it.” The ATP, which runs the men's tennis tour, did not immediately respond to messages left for comment.

Under the World Anti-Doping Code - to which the ITF is a signatory - Odesnik faces a possible two-year suspension for possession of a prohibited substance.

Odesnik, who is currently ranked No. 98 in the world and has a career-high ranking of No. 77, reached the quarterfinals at the Brisbane International and the second round of the Australian Open.

He has since played in four tournaments in the United States, advancing beyond the first round only once.

The Australian Sports Anti-Doping Authority was aware of the charges against Odesnik.

“ASADA is aware of the matter announced by the Australian Customs and Border Protection Service,” ASADA said in a statement. “Under its legislation, ASADA has power to receive information from Customs and to carry out investigations into possible violations of anti-doping rules.

“Under its legislation, ASADA is unable to provide further comment at this time.” Marion Grant, a spokeswoman for the Customs Service's Border Protection Enforcement, said: “This prosecution ... should act as an important deterrent for other elite athletes who are considering similar activities.” Australia's Customs Act has an extensive list of performance-enhancing substances subject to import control.