Sports journalist Damian Barrett told The Footy Show the 38-year-old was "set upon" in a Perth prison.

Cousins is serving a 12-month sentence in late March relating to drugs and domestic charges and has been in jail for seven weeks.

Barrett said the Brownlow Medallist and premiership-winner was assaulted after refusing to play in a football match.

Cousins has struggled to overcome a well-documented drug addiction in recent years.