Former Knights superstar and premiership winner Matthew Johns has called on the NRL to reform one particular area of the current HIA protocols.

Johns has spoken out after the NRL announced last week that there will be a mandatory 11 day stand down for players who suffer a grade-one concussion since the last time they played.

Although the players who fail their HIA will be stood down, Johns has taken a swipe at the NRL on SEN 1170 The Round Up about the rule that will see a player stay on the sidelines for 15 minutes even if they pass their HIA test.

"I do not understand the 15-minute HIA," Johns said.

"If you walk in there and the independent doctor assesses you and says, ‘Ok, look you're fine to go', just go straight out there."

"It's unnecessary, I can't get my head around it, I don't know why, they might say the doctor needs to take time."

While on the conversation of HIA protocols, Johns suggested that the offender should be off for the same amount of time as the victim who received the head knock.

Johns believed that the NRL should drop the HIA to ten minutes, whilst the sin-bin time should be moved down from ten minutes to five.

"As far as the sin bins, I've said for a couple of years they should bring back the option for a five-minute sin bin, ten minutes, boy it takes a piece out of a side," he continued.

"I can understand here there's a few cracks in the system, simply because we're reacting to what we've learnt, I think it's better to react and get it slightly wrong rather than just sit on their hands."

"I think now it's clear we've got a little problem with the 15 minutes (HIA), if the doctor in there gives the player the all-clear he should be able to go back into the contest."