Adelaide United's Ken Ilso has been suspended provisionally from the A-League after his A-sample tested positive for Benzoylecgonine - a substance banned by the World Anti Doping Authority and the FFA's National Anti Doping Policy.
The 32-year-old forward took the test in question with Australian Anti-Doping Agency officials on January 27 - the day after Australia Day - and the substance present in the sample, Benzoylecgonine, is known as a metabolite of the recreational drug cocaine.
Ilso will not be allowed to play in the A-League or any WADA compliant sport until the results of his B-sample are analysed and returned - with the FFA then deciding whether to issue an Anti-Doping rule violation.
"Adelaide United fully supports the policies of FFA and the Australian Sports Anti-Doping Authority (ASADA),” Adelaide United chief executive Nathan Kosmina said.
"We have and will continue to work proactively with both organisations and provide necessary support to Ken as due process is undertaken.
"As the matter currently sits with FFA and ASADA for investigation, we are not able to comment further.
"Nevertheless, Adelaide United recognises the significance of the matter and wants to ensure our members, fans, and stakeholders that we will treat this with the utmost seriousness and sensitivity.
"We ask that commentary on this situation also shows sensitivity to the issues involved."
Ilso has made 19 appearances for the Reds this season, scoring three goals - with two coming against Wellington Phoenix in November.
He joined Adelaide in the off-season after stints in Malaysia with Penang and Kedah FA.