What is one of the definitions of obstruction in baseball?

Obstruction in baseball refers to a situation where a defensive player hinders the progress of a base runner without the ball in their possession. When a defensive player simulates a tag while not actually in possession of the ball, it is considered a form of obstruction because it creates an unfair advantage for the defense and may confuse the runner. The key aspect of this definition lies in the player's actions—whether intentional or unintentional—preventing the runner from advancing freely.

This concept is important as it protects the base runner's rights, ensuring that they can run the bases without unnecessary interference. If a runner is obstructed, they may be awarded the base they were attempting to reach at the time of the obstruction, depending on the circumstances. Understanding this definition is crucial for umpires to make accurate calls during games and maintain fair play.