Fifa will trial substitutions for actual or suspected concussion at the Club World Cup in Qatar next month.
Each team will be able to use one concussion substitution per match with the switch able to happen regardless of the number of changes already made.
It will be the first international competition to trial the proposal.
Teams can use five normal substitutes per game but to avoid disruption they will only have three opportunities to make changes, in addition to half-time.
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Tigres from Mexico, Egyptian club Al Ahly, Bayern Munich from Germany, South Korea's Ulsan, Auckland City from New Zealand, hosts Al Duhail and the winners of South America's Copa Libertadores will compete for the title next month.
The introduction of concussion substitutes was proposed as a measure to help tackle football's growing concern over dementia.
Campaigners have been calling for changes in the way the game is played after several former players were diagnosed with dementia, which has been linked to heading footballs.
Some football associations have already banned heading in children's games or training.
The Professional Footballers' Association is setting up a task force to look at the issue.
BBC Sport understands the Premier League is awaiting the final protocols for how concussion substitutes could work in the English game before deciding with clubs when it will begin its own trial.
The Football Association also remains keen to implement the trials at the earliest opportunity.
It is thought teams may be able to use concussion substitutes in the FA Cup fourth round, which is due to run over the weekend of 23-24 January.
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