Incidents of foul play can now trigger an 18th man to be activated by NRL clubs after the Australian Rugby League Commission on Tuesday approved revised criteria around an extra substitution.
After consultation with clubs and players the ARLC has signed off on changes to their controversial original proposal for an 18th man for three failed head injury assessments only.
Scrapped is the notion of the development player, which raised concerns about the effectiveness of having an 18th player on the bench for extreme circumstances in the first place.
The new rule approved for use from round five will allow clubs to select an 18th man one hour prior to kick-off from their 21-man squad named at the start of the week.
That extra substitution can only be activated once three players suffer a concussion, or a player suffers a game-ending injury as a result of foul play in which the offender is sent off or sin-binned.
The introduction of an extra substitution for foul play follows calls from players and coaches and stops clubs being disadvantaged in games due to illegal behaviour.
ARLC chairman Peter V'landys said the commission will be flexible with the changes and adapt them if need be.
"Player wellbeing is a priority for the commission and this additional safety net ensures players continue to be protected,'" he said.
"Our clubs are outstanding in the way they detect and monitor head injuries and the activation of an 18th player in rare cases of three failed HIAs during a game will ensure continued strict compliance throughout a match.
"We've also approved an 18th player to be activated when a player suffers a match ending injury because of foul play where the perpetrator is sin-binned or sent off.
"Why should a team be disadvantaged by an act of serious foul play?
"This was a strong message from all clubs and fans and the commission has listened to that feedback.
"We've also listened to clubs and players about the criteria of the 18th player used and will allow the club to select any of its registered players which will enable the most effective team combination on game day."
The changes follow wide-spread criticism that the original proposal was too soft and reactionary after three Cronulla players failed HIAs in their loss to Parramatta in round three.
It was just the second incident in the NRL's history in which three players from the one team were lost to concussion during a game.
However, it raised concerns for player welfare and the ongoing quality of matches given the tightening guidelines around concussion protocols in the sport.