A normal substitute in cricket can field for an injured player but cannot simply take over that player's full role. A concussion replacement is different. Once approved, the replacement can become a full participant in the match, including batting and bowling where permitted.
That makes the rule unusually powerful—and explains why it includes medical checks, paperwork and a final decision from the match referee.
When can a concussion replacement be requested?
Under ICC playing conditions, the process begins when a player suffers a concussion or suspected concussion following a head or neck injury during the match. The team medical representative, sometimes in consultation with the match-day doctor, assesses the player.
The request is not meant to be a tactical substitution. It must identify the injured player, describe the incident and name the proposed replacement. The medical assessment is central: the team cannot activate the rule merely because a batter has been struck on the helmet or a fielder has fallen heavily.
What does “like for like” mean?
The proposed replacement should be like for like. That phrase does not require two players to have identical statistics or styles. The match referee considers the role the injured player was likely to perform for the rest of the match and the normal role of the proposed replacement.
For example, replacing a specialist batter with another specialist batter is usually easier to justify than replacing that batter with a frontline all-rounder who could also deliver a full bowling workload. Similarly, a wicketkeeper's replacement would normally need to cover the keeping role.
The objective is to restore the affected team without giving it an excessive sporting advantage.
Who makes the final decision?
The team submits its request, but the ICC match referee decides whether to approve it. The referee can ask for more information and may impose conditions if the nominated player's usual role would give the team too much extra value.
The referee's decision is final under the playing conditions. The opposition captain does not have a veto.
Can the replacement bat and bowl?
Yes. An approved concussion replacement is not restricted like an ordinary substitute fielder. The player can bat, bowl and field as part of the playing side, subject to any conditions attached by the referee and any restrictions inherited from the replaced player.
That distinction matters. An ordinary substitute generally covers fielding duties; a concussion replacement takes the injured player's place in the match itself.
Can the injured player return later?
No. Once the concussion replacement is approved, the replaced player takes no further part in that match. Even if symptoms improve, the change cannot be reversed simply because the original player feels ready to return.
This protects the integrity of the replacement process and, more importantly, reduces pressure on an injured player to resume competition prematurely.
What happens to warnings and suspensions?
A replacement does not erase everything attached to the original player's participation. ICC conditions state that the concussion replacement inherits relevant warnings, penalty time and suspensions imposed on the replaced player.
That prevents a team from escaping an existing restriction through the substitution process.
Do both players count as having played?
Yes. For records and statistical purposes, both the replaced player and the concussion replacement are considered to have played in the match. Their individual performances are recorded normally.
This can produce a scorecard with more than 11 named participants for one side even though the team never has more than 11 active players at the same moment.
Why the rule can create controversy
Disputes usually focus on whether the replacement is genuinely like for like. Player roles are not always neat. A batter may bowl occasionally, a bowling all-rounder may have improved dramatically with the bat, and a wicketkeeper may also be one of the team's best scorers.
The referee must judge expected function, not simply compare labels. Two reasonable observers can therefore disagree even when the formal process has been followed.
The bottom line
A cricket concussion substitute is a full replacement approved for player safety, not a routine tactical change. Medical staff identify the concussion or suspected concussion, the team nominates a replacement, and the match referee decides whether that player is sufficiently like for like.
For more rules coverage, read our guide to cricket fielding restrictions and browse the Cricket section.
