Winger Epi Taione has decided to leave Sale after receiving an 18-week ban for biting Munster's Denis Leamy in a Heineken Cup tie in January.
Sale launched an internal inquiry into the affair but the Tongan has decided to leave and look for another club.
"The best thing is to release myself from my deal and concentrate on a new start and a new challenge," he said.
"I am a proud man and I feel I have not delivered my part of the deal for Sale. I would like to publicly apologise."
Taione only made one Premiership start for Sale following his move from Newcastle last summer but is keen to find a new club to keep his international chances alive.
"I came here to play a huge part in a winning team and circumstances and injury have prevented me from doing that," he said.
"I let down the club, my team-mates and the fans through a moment of madness for which I am truly remorseful.
"I am available to help my country reach the World Cup via this summer's qualifying matches.
Sale chief executive Niels de Vos described Taione's decision to leave as "very brave and honourable", saying it showed him to be "a man of great integrity".