Appeal play

In baseball, an appeal play occurs when a member of the defensive team calls the attention of an umpire to an infraction that they would otherwise ignore.

Rare situations with a viable appeal on a runner who misses his force base require the umpire to recognize an apparent fourth out.

Suppose that a fielder, with the live ball, touches third base and tells the nearest umpire, "I think they left too early."

This is a legal and viable appeal, and so the umpire should call the runner out and direct that his run shall not count.

When a batter appears to have swung at a pitch, but the plate umpire calls it a ball, a member of the defensive team (by rule the manager or catcher, though the pitcher often appeals and is usually recognized) may appeal for information from a base umpire with a better view of the pitch on whether the batter swung.

The plate umpire is not required to ask for assistance if they believe the request is making a farce of the game.

An appeal may be executed if a fair ball becomes dead by leaving the playing field or becoming unplayable (home run, ground rule double, wild throw into stands/dugout, stuck in fence, drunk fan runs onto the field and steals the ball, etc.)