The AFL has confirmed that players have repeatedly been banned from playing for breaches of the league's controversial illicit drugs policy.
The code's three-strike policy means positive tests are not made public until a third positive reading. Only club doctors are made aware of any positive tests.
But AFL chief Andrew Demetriou said while test results remain secret, club doctors have prevented some players from playing.
"Club doctors would tell the coach or the football manager that a certain player was not in a condition to play," Demetriou told The Australian.
"He does not need to specify any injury or illness, just that he considers the player not well enough to play.
"It is not uncommon if a club doctor who is treating a player, for depression say, to tell the coach that the player is not available for selection because of illness."
Demetriou said player confidentially had not been compromised.
AFL medical officer Peter Harcourt told last week's AFL summit on drugs that some players were deemed "not fit to play" while they were undergoing rehabilitation and had been stood down from matches.
"You don't have to be on two strikes to be forced to stop playing," Demetriou said.
"If a player tests positive just once and the AFL medical officers believe he needs prolonged rehabilitation then he will not be allowed to play."
The Australian is reporting at least four players tested positive twice to banned drugs last season.