Why Robinson believes 'medical sub' is worthy of debate

Sydney Roosters coach Trent Robinson believes Parramatta's loss of Ryan Matterson in Thursday night's defeat of Melbourne is likely to spark debate about whether the NRL should follow the lead of AFL and introduce a 'medical sub'.

Robinson said he immediately thought of the new AFL rule after Matterson was ruled out of the match following an incident involving Felise Kaufusi that resulted in the Storm second-rower being charged with grade two dangerous contact.

The Roosters finished with 16 players against Manly after captain Jake Friend was concussed and he is unlikely to play next week as the club formulates a plan with specialists for his return.

The AFL this week announced that teams will be permitted to use 23 players for each game instead of the regular 22 but that extra player will only be able to take the field after club doctors have assessed an injured or concussed player as "medically unfit" to continue.

To be eligible for a medical substitution, the club's doctor must decide that the injured player will be unable to play a game in the next 12 days – the same time period that a concussed player must sit out under new protocols introduced by the AFL for this season.

The NRL requires players who suffer a concussion to sit out for 11 days unless they receive a clearance from an independent doctor.

Robinson said he was undecided whether the NRL should introduce a 'medical sub' but believed it was a subject that warranted discussion.

"It's an interesting one," Robinson said. "What the NRL has done this year is bring in the independent doctor within the 11-day period. They've made a small step to taking it out of the hands of the wins and losses of the clubs, to say we need to do a bit more.

"The AFL have got stand-down the following weekend. It was a good example last night, where Ryan Matterson had to leave the field – they obviously get the interchange there, but there was pressure on Parramatta through no fault of their own.

"I was thinking about it last night when I saw that, the first round of the concussion sub [in AFL]. I haven't landed on a spot, but I thought it was a very good example last night of when it possibly could be used.

"That was an example where we sit there and we go, would that have helped? That's up to the NRL to continue to look at."

The introduction of an 18th man as an emergency player had been considered by the NRL's competition committee on an almost annual basis but there were concerns about the impact a fresh player would have on the game.

The AFL also had concerns about the possibility of coaches manipulating the rule and only finalised the rule 24 hours before Thursday night's season opening match between Richmond and Carlton.

"People want the attrition of our game and the hardness of our game, and we also need to protect the players. That's where there is a gap in between the two," Robinson said.

"If you can't finish the game, even if it's not foul play, that's like any other injury. You've got to get on with it and it is just up to the team to make up for the loss.

"On the other side, we have moved into a space in the last few years where it's a real grey area. People don't know what a head injury does like they do a hamstring injury, so how do we protect the game and its players?"

The Roosters are without captain Boyd Cordner until round 12 as he recovers from a series of concussions – the last of which ruled him out of NSW's State of Origin campaign after he was forced from the field in the series opener.

Friend will miss Sunday's clash with Wests Tigers and is unlikely to play next weekend.

"My gut feeling is he won't be playing round three," Robinson said.

"He has got one more specialist to see and then we will sit down and discuss where he is at next week between coach and doctor and Jake to see what is next. You just need to give us a little bit more time and we will get our plan together for Jake.

"Jake's a warrior first and foremost and he has been his whole career. Now he is a captain and a father so you get a mix of both. The warrior in him will always be there but he knows he needs to get some work done before we sit down and have a discussion."