Football's Concussion Substitute Is Permanent, Which Is the Problem

What the rule currently is

Competitions may permit additional permanent concussion substitutions. A player with an actual or suspected concussion is substituted, takes no further part, and the change does not count against the team’s normal substitution allowance.

The “additional” part is genuinely good design. Before it, removing a concussed player cost a substitution, so the team paid a tactical price for a medical decision — the worst possible incentive to attach to a head injury.

Making it free removes that. As far as it goes, it works.

The permanence is the whole problem

Here is the decision a doctor actually faces.

A player takes a blow to the head in the 30th minute of a cup final. They are talkative, they want to continue, and the doctor is not sure. Concussion frequently presents ambiguously in the first minutes, and the reliable assessment takes time and quiet, neither of which exists on a touchline.

Under the current rule, the doctor’s options are: let them play on, or end their match permanently.

There is no option to check.

So a doctor who is 60% confident the player is fine has to weigh a small medical risk against a certain, irreversible sporting cost — imposed on a player who is telling them they are fine, in front of a crowd, in a match that may define a season.

That pressure is exactly what a protocol is supposed to remove, and this one leaves it in place.

Rugby designed this away years ago

Rugby’s head injury assessment does the opposite thing.

A player leaves the field for a 12-minute off-field assessment while a temporary replacement plays. Fail it and the replacement becomes permanent. Pass it and the player returns.

The temporary replacement is not a convenience. It is the mechanism — it makes the assessment free to the team, so the decision to check carries no cost at all.

Remove the cost and you remove the reason not to check. That is the entire design, and it is why rugby’s protocol works despite the underlying medical uncertainty being identical to football’s.

Football has the same problem, has watched a neighbouring sport solve it, and has adopted the half of the solution that was easy.

The case IFAB has made for permanence

IFAB’s position is not indefensible, and it rests on two arguments.

Abuse. A temporary substitute is an extra pause and an extra body. A team could claim a head injury to break an opponent’s momentum, get a free rest, or buy ten minutes with an extra player warming. Football’s substitution rules have been gamed for a century, and any new category of stoppage will be tested.

Erring toward removal. If in doubt, sit them out. A permanent rule enforces the cautious answer: once a doctor is worried enough to intervene, the player’s day is over. A temporary system creates pressure to return a player who has passed a fifteen-minute test but should not be playing.

That second argument is the serious one. Rugby’s own protocol implicitly concedes it — HIA2 within three hours and HIA3 at 36 to 48 hours exist precisely because the pitchside test is known to be insufficient. Some players pass and are concussed.

Why the campaign is probably right anyway

Twenty-eight competitions, including the Premier League, have written to IFAB asking for a trial.

The strongest argument for them is behavioural rather than medical. The question is not which system identifies concussion better in the assessment room — it is which system results in more players being assessed at all.

A permanent rule suppresses assessments. Doctors under pressure, players insisting they are fine, managers who need their best player: the current design makes the safe choice expensive, so it happens less often than it should.

A temporary substitute makes checking free. Some concussed players will pass and return, which is a real cost. But they would have stayed on anyway under a rule where the alternative was permanent removal.

And note what is being asked for: a trial. Football has the mechanism for exactly this — controlled experiments in real competitions, as with the ABBA shootout sequence and semi-automated offside. Refusing to trial a welfare measure is a harder position to hold than refusing to adopt one.

For the rest of the laws, see soccer rules, and for how football handles other in-match decisions it cannot make quickly, how VAR works.