Penrith have confirmed "a significant number" of players and staff have been forced into isolation after a string of positive cases within the squad emerged.
The Panthers confirmed on Wednesday that their pre-season training planning for this week has been postponed, with members of their football department having either tested positive for the virus or have been identified as close contacts.
The NRL is continuing to battle with the pandemic as Australia looks to combat record case numbers nationwide.
Penrith join the Broncos and Knights in confirming multiple players have contracted the virus ahead of their pre-season returns.
"Penrith Panthers can confirm a significant number of the club’s NRL players and staff are currently self-isolating and will not be available for the recommencement of pre-season training this week," a club statement reads.
"The affected players and staff have either tested positive for COVID-19 or been identified as a close contact of a positive case.
"These individuals will only return to training after receiving clearance in accordance with NRL and NSW Government protocols.
"The club respects the privacy of the affected players and staff, and will be making no further comment on the matter at this time."
The league is set to force harsher restrictions on all 480 NRL players ahead of the new season, with players asked not to attend indoor venues this off-season.