The Bulldogs have suspended former international Reni Maitua from all duties after he was charged with assault on Monday night.
The club said in a statement the matter had been referred to the NRL's Integrity Unit and they would comment further on it once those investigations were completed.
It is believed the incident involved a taxi driver after Maitua left Kings Cross in the early hours of Monday morning.
Maitua took to Twitter to apologise.
"Deeply apologetic to the gentlemen involved, Canterbury, the fans, my family and the game in general.
"I have no excuses for my poor behaviour and will accept any punishment handed to me from the Powers to be. I was charged w common assault for pushing the gentleman's arm, by no means is that acceptable but certainly didn't strike anyone. Again I am truly sorry to everyone I have let down."
Maitua, 31, has only just returned to the club, where he won a premiership in 2004, after completing stints with Parramatta and Cronulla.
He served a two-year ban after testing positive to a banned substance in 2009.