Ilso has been provisionally suspended after a drug test following an A-League game on January 27 this year. Ilso's test, after he came on as a second-half substitute against Central Coast, showed traces of benzoylecgonine, a metabolite of cocaine.

The 32-year-old is seeking results from a further sample, known as a B sample.

"I am ... awaiting the results from the B test. Until these results are received I cannot make any further comments," Ilso said in a statement.

The FFA said Ilso's provisional suspension was mandatory under its anti-doping policy.

"While it is in place (he) is prohibited from participating in the A-League," the FFA said in a statement.

"(He) now has the opportunity to have his B-sample analysed before FFA takes steps to issue him with an anti-doping rule violation notice."

Adelaide United chief executive Nathan Kosmina said the club would offer Ilso support while the Australian Sports Anti-Doping Authority handled the case.

"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," Kosmina said in a statement.

Professional Footballers Australia chief executive John Didulica said the players' body would provide Ilso with "with all necessary legal and wellbeing support".

On-field, Ilso has largely failed to make an imprint in 19 A-League games.

The attacking midfielder has scored three goals for the Reds, including two in one game against Wellington last November, and has come off the bench in almost half of his appearances.

Born in Solrod Strand, Ilso was a Danish underage international who played in his native country until moving to Germany in 2011.

Ilso has since spent time in China, Singapore and Malasyia before signing with Adelaide.

Australian Associated Press