A feasibility study - initiated by the governing body, together with three years of GPS data from 11 NRL clubs - predicted that number to increase to 90 per cent by 2024.
"Fatigue is an important part of the game, but we need to look at decreasing injuries as well," Greenberg said.
"Player athletes have never been fitter, faster and stronger. So we expect this will change the way that the coaches and high performance units at clubs manage their athletes."
A decision on the length of the shot clock has yet to be determined, however the governing body is set to experiment with a time of 30-35 seconds in the under-20s competition over coming weeks, as well as dead-rubber NRL games towards the end of this season.
The rules will state that when a team fails to pack a scrum or kick the dropout when time expires, the offending team will be penalised.
"It's not looking to get players sprinting to scrums and speeding the game up," Greenberg said.
"But what it is looking to do is stop time wasting and stop players standing around for inordinate amounts of time, waiting for the ball to be put back into play.
"Fans will appreciate that, as will players, because it will give them some certainty on when the game starts again."
The implementation of a referee bunker is also close to being rubber-stamped, with the proposal set to be put before the ARL Commission later in the year.
Statistics reveal the video referee is being called on an average of four times a game, leaving fans waiting up to three minutes for live action to resume.
About 30 games have already been trialled with the new technology, with early results reducing time wasted by half.
- AAP
