The ARLC will consult with clubs and players before the rule is implemented from round five, which commences on Thursday, April 8th.
Although the 18th player would have benefited Cronulla on Sunday evening, NRL teams have rarely found themselves in such an unfortunate situation.
As revealed by the NRL Physio, the previous instance of three players failing an HIA in the same team before last weekend was round seven of the 2016 premiership.
ARLC Chairman Peter V'landys said in a statement: "This is a dynamic environment. As a Commission we have always said we would be agile in changing rules when it is in the best interests of the game and this is one of those examples.
"We see this as an opportunity to give an emerging player a taste of first grade rugby league in their team's time of need. The 18th player will also have to be rotated weekly so you don't have a young player missing out on playing lower grades every week.
"All fans agree we don't want to see a situation where a club is left with one player on the bench and this rule change will provide insurance for all clubs. It will also only be activated in the most dire of circumstances for a club, so we don't see it having a material impact on games every week."
Speaking on Fox League's NRL 360, The Daily Telegraph's Paul Kent argued NRL coaches will look to "rort" the rule change to gain an upper hand.
"If you have two HIAs – which can be fairly common – there's a chance they will rort the third to get him off," Kent said on Tuesday evening.
"They should also look at this mandatory standown period, so if you come off to do the rort to get another guy on, you stand them down for seven to eleven days so that they miss next week.
"They'd start faking injuries – that's what will happen.
"We've had unlimited interchange, to some having to play half a game of reserve grade – all these different scenarios.
"And the whole thing that is consistent is that coaches can't be trusted – they're looking for a competitive advantage."
