Kootingal-Moonbi is the latest club to put a caveat on their participation in a 2020 season.
It comes as Group 4 chairman Ray McCoy announced on Sunday that he should learn on Wednesday what the New South Wales Rugby League's plans were regarding the "restrictions and protocols moving forward" for clubs.
McCoy also said Group 4 would "survey" clubs this week "to consolidate playing numbers in each grade prior to a general meeting in early June".
He said a draw would then be drawn up.
Group 4 said in late April that it was aiming for a July 25 season start, with the possibility of a seven-round competition that was followed by a final series involving all the teams.
But Sharpe said the Roosters would not participate in a 2020 season if "full crowds" were not allowed at games, the club did not get at least five home games and a full eight-team first-grade competition was not staged.
Those conditions were decided on a Roosters committee meeting about a month ago, Sharpe said.
"If there's any restrictions on crowds, we can't play," he said. "Our sponsors are all doing it tough under the Covid."
Added to that, he said, was the impact of the drought on the club's sponsors.
As a result, the Roosters' existing sponsorship deals would have to last two seasons - this year and next year, he said.
Last year's grand finalists had to determine if it was "financially viable" for them to play this year.
"And if they come back and say, "You can play, but you can only have 100 [people] in a crowd, or you're only allowed to have 500, we can't play," he said.
"Who's gonna police [a crowd of] 500; who's gonna turn up and say, "Bad luck, you've got 600. Therefore, there's a $5000 fine".
"There's just so many things [to weigh up]. Talk of going back to a competition ... it's really too early."
A relaxing of Covid restrictions means a maximum of 10 people can now training together, but they must practice social distancing.
The 10-max requirement obviously poses a problem for clubs, and McCoy said none had resumed training.