What constitutes obstruction in the game of baseball?

In baseball, obstruction is defined as an act committed by a fielder who, without the ball, impedes the progress of a runner. This can occur when a defensive player stands in the path of a runner attempting to reach a base. The key aspect of obstruction is that it involves a fielder who does not possess the ball; therefore, the runner is unfairly hindered in their advancement.

In essence, if the fielder does not have the ball and blocks the runner’s access to a base, it creates an unfair advantage for the defense and negatively impacts the offensive team's opportunity to advance. This rule is crucial for maintaining fairness during gameplay, ensuring that players have a clear path to the bases.

The other options do not align with the definition of obstruction as recognized in the rules of baseball. Holding the ball does not constitute obstruction or interfere with a runner’s movement if the fielder is in possession of it. An incorrect call by an umpire, while potentially impactful on the game, is not a form of obstruction as defined by the rules. Lastly, a catcher making a play from outside of their box is a situation that pertains to the rules of the catcher's position, but it does not classify as obstruction either.