Ryan Crowley had unwittingly taken methadone given to him for back pain when he failed his drug test, a tribunal has been told.

The hearing into the Fremantle footballer's drugs charge is understood to have been told the player took the drug usually associated with heroin rehabilitation as a strong pain-killing tablet.

Ryan Crowley's counsel has argued for a significant reduction in penalty Credit:Getty Images

It is understood the hearing was told an allied health professional unconnected to the club gave him two tablets, without declaring them to be methadone.

Methadone is an opioid commonly used as an analgesic or pain-reliever and in the treatment of drug addiction. It is considered a very effective treatment for chronic pain and is often used by cancer patients.