What Is Obstruction in Baseball?

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Obstruction in baseball is a rule seldom understood, but undeniably integral to the spirit and fairness of the game. This rule, falling under the umbrella of interference laws, can often be the tipping point in the heat of a match, swinging the momentum towards one side or the other. In this article, we’ll look into the nuances of what constitutes obstruction as we untangle its complexities. Notably, we’ll also highlight a few popular MLB instances where obstruction played a significant role, shedding light on its influence and its implications in shaping the course of the game.

What Is Obstruction in Baseball?

Obstruction in baseball refers to an incident where a fielder, who doesn’t have the ball and isn’t trying to field the ball, blocks a baserunner’s path. If there is an attempt to get the obstructed runner out, the umpire can stop the play, and decide where all the runners would have been if the obstruction hadn’t happened. If no one tries to get the obstructed runner out, the play continues normally. Afterward, the umpire can decide on penalties to cancel out the effects of the obstruction.

Types of Obstruction & Penalties

Obstruction in baseball can be categorized into two types.

The first type, previously known as “Type A” until the 2014 revision of the Major League Baseball Umpire rule books, occurs when a play is being made on the obstructed runner, or the batter-runner is obstructed before reaching the first base.

In this case, the ball is immediately declared dead. The umpire then uses their judgment to advance all runners to the bases they would have reached if the obstruction hadn’t occurred. The obstructed runner is entitled to at least one base beyond the last one he legally touched before the obstruction happened. If any runners preceding the obstructed runner are forced to advance due to the awarded bases, they also advance without the risk of being put out.

The second type, formerly known as “Type B”, happens when no play is being made on the obstructed runner. In this situation, the game continues until no further action is possible. The umpire then calls “Time” and imposes any penalties that, in his judgment, will offset the act of obstruction.

Noteworthy Instances of Obstruction in Baseball

Let’s look at a few significant instances of obstruction in baseball that bring out the difference between the two types of obstruction – previously known as “Type A” and “Type B”, and how they can influence the outcome of the game.

The Mariners’ Obstruction (August 6, 2004)

In a tied MLB game during the bottom of the tenth inning, an unusual event unfolded. The Mariners’ left fielder caught a fly ball, but the umpire ruled that the shortstop had obstructed the runner’s view, hindering him from leaving the base. This obstruction led to the runner being awarded home plate, resulting in the decisive winning run.

The A’s Vs. Red Sox Incident (October 4, 2003)

During game 3 of the 2003 ALDS, a collision between an A’s runner and the Red Sox third baseman resulted in an obstruction call. Misunderstanding the situation, the runner assumed the play was over and slowed down. He was then tagged out when attempting to reach home plate. The umpires classified this as a “Type B” obstruction, meaning the play should have proceeded normally.

The 2013 World Series Event (October 26, 2013)

A memorable moment from game 3 of the 2013 World Series involved a Cardinals’ runner getting obstructed by Red Sox’s third baseman who fell while attempting to catch a throw. The umpire ruled this as an obstruction and awarded the runner home plate, leading to the Cardinals winning the game. This situation was unique as the final decision was based on whether the runner would have reached home without the obstruction.

These cases demonstrate the critical role of umpires in interpreting the rules of obstruction, and how their judgment can significantly affect the outcome of the game.


The rules of baseball, while seemingly straightforward, contain a multitude of complexities, particularly when it comes to the principle of obstruction. As evidenced by the incidents involving the Mariners, the A’s, the Red Sox, and the 2013 World Series, these rules can be subject to various interpretations and can significantly influence the trajectory of a game. Umpires, thus, shoulder a hefty responsibility in making these critical calls. Their interpretive role not only ensures the game’s fairness but also maintains the spirit of competition inherent in this beloved sport.

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James Arnold
I'm James, and I live in Stanislaus County, California. I'm playing Baseball for many years, and I love this sport so much that I also encourage my kids (Danny and Sara) to play Baseball & Softball.