When can a player on the field be substituted?

A player on the field can be substituted anytime between plays with the umpire's permission. This rule allows for flexibility and strategic adjustments during the game. Substitutions can occur at various moments, allowing coaches to replace players for various reasons such as strategy, fatigue, or injury. The requirement for umpire's permission ensures that the game remains orderly and that all substitutions are properly recorded.

Substituting only at the end of each inning limits opportunities for tactical changes, restricting the ability to make necessary adjustments to the team's composition in response to the flow of the game. Likewise, restricting substitutions to timeouts would significantly hinder a coach's ability to optimize their lineup actively. Although a substitution must be conducted from the dugout and is logged appropriately, the dugout is not the sole place where player changes can occur, as substitutions can take place directly on the field with appropriate communication to the umpire.