What should umpires do if a coach brings a stopwatch onto the field?

If a coach brings a stopwatch onto the field and intends to use it for timeouts, allowing it can be appropriate under the rules of baseball. Coaches often use stopwatches to keep track of timeouts or other game-related timing elements, as long as the use does not interfere with the game or contradict any league regulations about the coach's responsibilities during gameplay. It is important for umpires to maintain the flow of the game while ensuring that the coach is not gaining an unfair advantage.

In this context, allowing the stopwatch provides a means for effective communication and strategy for the coach while still respecting the rules of play. Umpires need to be vigilant, however, to ensure that the stopwatch is not being used inappropriately for things like timing pitches or other actions that are not within the spirit of the game.