Second-rower Shawn Blore, 25, and his brother Dean have each pleaded guilty to a single assault charge stemming from the July 2024 incident.
Both had initially indicated they would fight affray charges before pleading guilty to the lesser charge in September over the late-night incident on Sydney's Little Hunter Street.
A court has previously heard the violence started when alleged victim Naaman Mikhael was asked to leave a restaurant for being aggressive towards another patron.
Mr Mikhael's lawyer told a previous hearing he was singled out by the Blores while a number of other skirmishes broke out.
Mr Mikhael was also previously charged with affray, but had his charge dismissed on mental health grounds in December when a magistrate found he did not start the violence.
Magistrate Jennifer Price accepted the prosecution case indicated Mr Mikhael did not instigate the violence and initially at least might have been acting in self-defence.
The circumstances of the Blores' involvement is due to be detailed during their sentencing at Downing Centre Local Court on Friday.
Shawn Blore switched from the Wests Tigers to Melbourne before the 2024 NRL season and has played in the Storm's back-to-back losing grand finals.
The former Samoa representative has played 81 NRL games and scored five tries.
His trip to this year's decider proved a rocky road, suffering a fractured larynx on the eve of finals.
Blore suffered the potentially life-threatening injury when he was hit while making a tackle against the Sydney Roosters and, unable to speak, was rushed to hospital.
He avoided being put into an induced coma or surgery but was told by doctors he would be sidelined for the remainder of the year, devastating news after previously recovering from back-to-back ACL injuries and a broken wrist when he was at Wests Tigers.
But Blore returned to the Storm's preliminary final side, helping them past the Sharks before playing 68 minutes in the 22-26 grand final loss to the Brisbane Broncos on October 5.
The former Penrith junior star's voice remains raspy and he's set to undergo speech therapy but has been given no guarantees of a full recovery.