Starting in 2024, MLB umpires will be enforcing the obstruction rule at 1B, 2B, 3B, in a similar manner as it is enforced at home by the Home Plate Collision Rule. Fielders could be penalized for obstruction if they are not in possession of the ball and impede a runner from touching a base. This goes for runners advancing to the next base and runners going back to their base for pickoffs. The exception to this is similar to that for catcher’s at home when the throw takes the fielder into the path of the runner. First basemen must be aware of their defensive set up with a runner on base as the fielder must give the runner a pathway to the entire base. This video shows examples of legal plays and runner obstructed plays.

The penalty for obstruction is not changed.

The base obstruction call is not reviewable. Home plate obstruction remains subject to replay review.

Scoring consideration: error on the fielder.