State of Origin forward Christian Welch says a way around clubs exploiting the use of an 18th man is to limit it to concussion cases with a mandatory one-match stand-down for players who have been substituted.
The ARL commission is meeting on Tuesday to discuss the introduction of 18th man for injuries.
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The Rugby League Players' Association called for the rule amid more than 20 injuries suffered at the weekend, however NRL stars remained split on the issue.
There are concerns that it is open to gamesmanship, with teams able to get a competitive advantage by injecting a fresh player into the match.
Melbourne prop Welch backed the introduction of an extra player, similar to what the AFL have brought in with their "medical substitute" rule this season.
But the Queensland representative wants to see the parameters narrowed in the NRL.
"I think it's important that it's kept as a narrow focus, strictly for concussions would be a positive for the game," Welch said on Tuesday morning.
"If you open it up to just injuries in general as the AFL has done, it could be abused.
"It's such a fatiguing game these days with the new rules that if you are down to one or two on the bench through a concussion, where you're looking after the long-term health of the player I don't think you should be penalised for that."
Welch's solution to save game's integrity
While the AFL have this season also introduced a mandatory 12-day stand-down policy for players who have suffered concussion, NRL players who fail a HIA are able to play the following match if they are cleared by an independent doctor.
Welch says players being automatically ruled out could stop the sub being used as a tactical ploy.
"It might be something to protect the integrity of the rule that if you do get subbed off with a concussion that you have to miss the following week," Welch said.
NRL boss Andrew Abdo earlier this year ruled out a mandatory period with concerns coaches or players could be deterred from declaring a concussion if it meant they would definitely miss the following match.
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