Masei Tavui, 19, was arrested on Tuesday after officers wearing tactical gear raided a property in Austral, west of Liverpool.
The NRL hopeful faced court later on the same day, when he was refused bail over the alleged murder of Dejan "Danny" Radulovic in Sydney's inner west on July 29.
A critically injured Mr Radulovic was found on Donnelly Street in Balmain following reports of an assault.
He was taken to hospital but died a short time later. An autopsy revealed he had suffered a gunshot wound.
Tavui faces a single charge of murder and he is due to return to Downing Centre Local Court on December 12.
The 19-year-old is yet to debut for the Tigers' NRL side but has played as a forward for affiliate club Western Suburbs Magpies in the SG Ball under-19s competition this season.
The Tigers will ensure the club's wellbeing team is on hand to support their players, who are on an off-season break.
Tavui's younger brother played for the club in the 2023 season of the Andrew Johns Cup, NSW Rugby League's regional representative under-16s competition.
The NRL did not comment on the murder charge on the grounds that Tavui was not a first-grade player and did not fall under the organisation's jurisdiction.
Police were told Mr Radulovic was injured during a fight with two men, who fled in a white Jeep.
The Jeep was found burnt out in nearby Five Dock with a firearm inside.
One other person has been charged over the incident and remains before the courts.