Football's lawmakers have approved "extensive trials" for additional permanent concussion substitutes.
The International Football Association Board announced on Wednesday that it had given the go-ahead for trials to start from January 2021.
A statement read: "Following consultation with key stakeholders and recommendations from the Concussion Expert Group (CEG) and the IFAB’s Football and Technical Advisory Panels (FAP-TAP), today’s annual business meeting approved extensive trials with additional permanent substitutions for actual or suspected concussion as of January 2021."
IFAB said that its members "agreed that, in the event of an actual or suspected concussion, the player in question should be permanently removed from the match to protect their welfare, but the player’s team should not suffer a numerical disadvantage".
In England, the Football Association had already stated that it was hoping to introduce the additional substitute at the "earliest possible stage" of the men’s and women’s FA Cup competitions, as well as the Women’s Super League and Championship.
It is understood the Premier League is waiting to see the detail of the concussion protocol from IFAB before making a decision.
Its clubs are meeting on Thursday, and there could be a vote on when and if to make the change at that meeting.
Highlighting the key reasons behind its decision, IFAB said: "This approach: prevents a player sustaining another concussion during the match as multiple head-injury incidents can have very serious consequences; sends a strong message that, if in doubt, the player is withdrawn but there is no numerical or tactical disadvantage by prioritising the player’s welfare; reduces the pressure on medical personnel to make a quick assessment; and is simple to operate and can be applied at all levels of the game, including most of football that is played without doctors or medically qualified staff available on site."
IFAB also approved the extension of the law allowing up to five substitutions in top-level competitions. For domestic competitions this has been extended to 31 December 2021 and for international tournaments to 31 July 2022.
On the handball law, which has been the subject of so much controversy so far this season, IFAB said its members "agreed that further clarification should be considered at the Annual General Meeting".
IFAB added: "It was agreed that not every touch of a player’s hand/arm with the ball is an offence. In terms of 'unnaturally bigger’, referees should judge the position of the hand/arm in relation to the player’s movement in that phase of play."
The AGM will will take place via video conference on 5 March next year.