How does the umpire handle an illegal substitute reported by a scorekeeper or fan?

When an illegal substitute is reported, the proper response from the umpire is to call the illegal substitute out. This ensures that the integrity of the game is maintained, as illegal substitutions can lead to advantages that disrupt fair play.

Calling the substitute out is a decisive action that reflects the rules governing player eligibility and participation. It prevents any potential confusion regarding the legality of players on the field and reinforces the accountability of coaches and players in adhering to the established rules.

The other options would not adequately address the situation. Not taking action without official confirmation would allow the illegal substitute to potentially impact the game further without correction. Allowing the substitute to remain in the game dismisses the seriousness of the violation. A warning to the coach may not be sufficient, as it ignores the immediate impact that an illegal substitute may have already had on the game. Therefore, the umpire's action of calling the illegal substitute out is necessary to uphold the standards of the sport.