The NRL Integrity Unity has outlined how it deals with disciplinary matters involving players.
NRL General Manager of Integrity Nick Weeks said for non-police matters, like the recent Paul Gallen tweet, the NRL is free to act immediately by issuing the player with a breach notice.
The player is then given an opportunity to put forward any mitigating factors before any penalty is imposed.
However, Mr Weeks said that, in criminal matters, the NRL is careful not to interfere with the judicial system.
"We need to ensure we don't act in a manner that influences or prejudices a criminal investigation or hearing," he said.
For matters before a court or judge or at trial, it could be considered an offence for the NRL to influence the outcome of the matter by publicly commenting.
"We need to wait and let those matters run their course, and give players the opportunity to have a fair hearing until the matter is completed," Mr Weeks said.
"Then we can assess all the factors and act."
Mr Weeks said this applied to the case involving South Sydney player, Kirisome Auva'a – who pleaded guilty to assaulting his former partner in Melbourne in January.
The NRL followed due process and waited for the court proceedings to finish.
"The NRL will now review all available material including, legal documents, and work in conjunction with the Rabbitohs to determine whether any further sanctions are appropriate," he said.