Under the trial, which will also be implemented in other competitions including the Premier League, if play is stopped due to a goalkeeper requiring medical treatment, the coach must immediately nominate an outfield player to leave the pitch for a minute after play resumes.
If the coach fails to nominate a player within 10 seconds, the captain of the team must be the one to leave the field.
When Santos beat Vasco 3-0 on Sunday, the rule was invoked for the first time in the Brazilian top flight when keeper Gabriel Brazao requested medical attention.
The referee told captain Neymar to leave the field as the Santos coach did not nominate another player within 10 seconds.
Neymar, 34, made two appearances for Brazil off the bench in this year's World Cup, scoring a late penalty in their 2-1 loss to Norway in the round of 16.