EPL to Start Permanent Concussion Substitution Trials from January.
English football lawmakers and the International Football Association Board (Ifab) are set to make new rules on substitution. It will be called concussion substitution and it will be put to trial from January 2021. This can be traced back to when David Luiz and Raul Jimenez had a head coalition and Luiz had to continue because of the substitution rule.

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 if they want.
However, Premier League clubs have voted against the use of five substitutes for a third time, despite the move by the International Football Board 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. Also it is gathered that player’s welfare should be 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 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.