Demetriou revealed at an animated media conference to launch this summer's NAB Cup series that he had asked Australian Crime Commission permission to advise the club.
So far details of another player under investigation has not been disclosed while ACC and AFL authorities have confirmed that a probe is under way into allegations of multiple Essendon players using performance enhancing substances.
Demetriou revealed he had not been given permission to inform the latest alleged club that a player is being investigated.
Demetriou and his advisors are understood to be want to advise the club under ACC investigation.
"Yes and we'll be seeking that clarification from the Australian Crime Commission," Demetriou said.
The league chief repeated recent advice that he is only allowed by ACC authorities to advise that all AFL clubs are vulnerable to infiltration of illegal drug use and corruption.
"I've had it clarified this morning with the Australian Crime Commission that we are not able at this point to notify the particular club where there is a case involving the possibility of WADA-prohibited performance-enhancing drug use for this one player," Demetriou said.
"In addition, I want to make it clear that we have not been told the identity of the player in question so we don't know whether this player is a current player or not a current player."
Demetriou claimed while he and his staff have not been told of the latest player or club under investigation, that individual or club may have already have been told by the ACC.