FREMANTLE tagger Ryan Crowley is unlikely to face the AFL Anti-Doping Tribunal until after the same panel has delivered its verdict on Essendon on March 31.

AFL CEO Gillon McLachlan defended the League's preference to have one Anti-Doping Tribunal panel, but acknowledged the "timing challenges" caused when multiple cases need to be heard.

Crowley, who has been provisionally suspended since September last year, is waiting on a hearing date after testing positive to a banned substance contained in a painkiller last season. 

"The challenge is we have one Tribunal and we are not able to be in contact with them at the moment," McLachlan said on Friday.

"There's some timing challenges right now, but what we have always liked, and why we've always had one Tribunal … is some consistency in the Tribunal so you get consistency of application and decision making. 

"I think broadly everyone understands and supports that. It throws up some challenges now."

Crowley tested positive to a 'specified' substance after playing Greater Western Sydney on July 13 last season, and the results of his 'B' sample weren't known until after the Dockers had been bundled out of the finals by Port Adelaide. 

Ross Lyon yet to speak to Crowley about painkiller

McLachlan said there were "nuances" in Crowley's case that led to a six-month timeline between the midfielder's 'B' sample testing positive and his show-cause notice being made public.  

"Everyone is satisfied broadly that the systems and the protocols have been followed," he said.

"There are particular nuances of this case, which mean it has been six months.

"The player has been suspended essentially for the majority of that time.

"I've got great faith in the guys administering at our end and we'll work through those challenges."

McLachlan also addressed Thursday's revelation that Melbourne recruit Heritier Lumumba sought a special ruling of the League's illicit drugs policy in 2013. 

"I can't really comment as you know, other than to say no dispensations for variations of our illicit drugs policy have been given. I think the consequence of that is self-evident," he said. 

Lumumba asked the League how his case would be treated if he recorded a positive test due to passive ingestion of cannabis.