The Premier League has said it hopes to start permanent concussion substitution trials from January.
It follows football’s lawmakers, the International Football Association Board (Ifab), approving trials in 2021.
The new rule means permanent substitutions can be made if a player suffers a head injury, even if all replacements have already been used.
To avoid potential abuse of the rule, opposition teams will also be able to make a change at the same time.
However, Premier League clubs have voted against the use of five substitutes for a third time, despite Ifab’s confirming an extension to the rule on Wednesday.
Instead, the number of top-flight players allowed on the bench has increased from seven to nine.
This measure will come into effect from matchday 14, which begins on Saturday.
“With player welfare the Premier League’s priority, clubs agreed in principle to introduce additional permanent concussion substitutions following approval of the trial by the International Football Association Board yesterday,” the Premier League said on Thursday.
“The Premier League will look to implement protocols which will allow a maximum of two concussion substitutes to be used per team, with the opposition side able to use the equivalent number.
“The additional concussion substitutions may be made regardless of the number of substitutions a team has made already.”