urprisingly, little is said about the mechanics for unlimited substitution in the USSF’s Guide to Procedures for Referees, Assistant Referees and Fourth Officials. The information on mechanics is limited, and crews around the country have developed their own systems of dealing with it.

Don’t let your attention stray

What unlimited substitution means for soccer officials is that they must pay attention to substitution opportunities, granting them only when permitted by the modified Laws of the Game. The assistant referees play a major role in helping the referee recognize when a substitution opportunity occurs and a player is waiting at the halfline to enter the game.

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