Fremantle forward Jesse Hogan is under police investigation after breaching Western Australia's quarantine laws.
Hogan confirmed to police that he had a female visitor attend his home on September 22 - just a day after Fremantle arrived back to Perth following their final-round loss to the Bulldogs in Queensland.
The visit breached the WA government's quarantine directions orders, and the matter is now under police investigation.
Police have ordered Hogan to complete the remainder of his 14-day quarantine period in a hotel.
Hogan could also receive a club-imposed sanction.
"Our players and staff are all well aware of the restrictions they are all required to comply with while in quarantine and the broader obligation the club has to the community to do so," Fremantle chief executive Simon Garlick said.
"We have worked very closely and effectively with WA police, the state government and the AFL throughout the year, which provided us with the opportunity to complete our AFL season.
"The cooperation and understanding we have received from all parties during the season is something we do not take for granted. This makes the breach even more disappointing and incredibly frustrating.
"We will wait for Jesse to complete his hotel quarantine before determining what club-imposed sanction he will face.
"In the meantime, we will be reinforcing with all quarantined players and staff the importance of strict adherence to their quarantine protocols."
Fremantle has also advised the AFL of the matter.
Hogan has endured numerous off-field incidents during his short time at Fremantle.
The former Demon was overlooked for Fremantle's season opener in 2019 for breaking the team's alcohol rules.
Later that year, Hogan was taken to hospital after flipping his car on a Sunday morning.
Hogan has also taken time away from the club to work on his mental health.
The 25-year-old had fallen so far out of favour earlier this season that at one stage he was being trialled as a defender during practice matches.
Hogan managed to work his way back into the senior side later in the season, and he still has one more year remaining on his current contract.
Coach Justin Longmuir recently said he expects Hogan to be at the club in 2021.