A video purportedly showing New Zealand international Nelson Asofa-Solomona swinging punches outside a Bali nightclub prompted Australian rugby league authorities on Monday to announce they were launching an inquiry.
Footage circulating on social media allegedly shows the Melbourne Storm forward involved in the violent street brawl on the Indonesian holiday island over the weekend.
The club said in a statement it had reported the incident to the National Rugby League's Integrity Unit.
"Storm has launched a full investigation into what has occurred," it said. "Storm takes these types of incidents very seriously and will not be making any further public comment at this time."
According to the Sydney Daily Telegraph, Asofa-Solomona got involved after Melbourne winger Suliasi Vunivalu was punched in an unprovoked attack.
"The Integrity Unit is working with both the Storm and the player to determine what has happened," the NRL said.
NRL players have a history of questionable behaviour, with two suspended over an alcohol-fuelled incident on an international flight in March.
Just prior to that, young playmaker Tyrone May was suspended indefinitely after being charged by police for allegedly filming and sharing images of sexual acts with two separate women.