How it works
During the trial, teams will have two additional permanent concussion substitutions per game [APCs].
If the referee stops a match for a potential concussion injury to a player, the medical staff of that player's team will enter the field of play to make an assessment while the tunnel doctor will review video footage of the incident.
The team doctor will have as much time as is required to make an on-pitch clinical assessment of the player.
In the event of one team having to make a change due to clear symptoms of concussion - or clear video evidence thereof - the opposing team will also be allowed to make an additional substitution at a time of their choosing.
It was agreed the opposing team should be given an additional substitute in this scenario to ensure neither side can claim to have a possible advantage by having more fresh players on the field.
The substituted player will not be allowed to return to the field of play.