Cronulla Sharks chief executive Lyall Gorman insists Ben Barba is the only player from the club to have tested positive to drugs since their grand final win.
The NRL champions announced on Tuesday they had released the full-back, who has been suspended for 12 games.
Gorman said the club had been told by the league that Barba was the only player to test positive.
"We're not aware of any players that have tested positive since then," he told a news conference.
He added: "We've been advised by the NRL that no other player has tested positive during that period."
Gorman said he was unaware of the details of the Barba incident, but feels the 27-year-old simply made a bad decision.
"I think he's made a poor choice on a poor day," he said.
"Whether he's got carried away with the celebrations, I don't know the exact circumstances of when this occurred, but obviously a poor choice."
The Sharks ended a 49-year premiership drought with a 14-12 win over the Melbourne Storm in the grand final on October 2.