FIFA have been urged by concussion experts to allow the Premier League to undergo trials of rugby-style temporary substitutes which would permit players to return to action after successfully passing a head-injury assessment (HIA).
The issue of concussion substitutes was further brought into the spotlight on Friday when Southampton defender Jan Bednarek was desperate to carry on playing after a heavy fall on his neck - claiming he was fine - despite his team's doctors insisting it wasn't safe.
The current protocol is that teams are allowed an extra substitute if someone has to be replaced due to concussion but the player in question is not allowed to return after going off even if they have passed an assessment.