What Is a Ground Rule Double in Baseball?

Discover the Unwritten Rules of the Diamond: Understanding Ground Rule Doubles
Written by Mark Bailey
Last updated on

A ground rule double is a baseball term for a hit ball that bounces and goes out of play according to the specific ground rules of a ballpark, usually resulting in the batter and any base runners being awarded two bases.

  • Ground rule doubles are awarded by umpires when a fair ball becomes unplayable due to certain parts of the field.
  • Ground rules vary from stadium to stadium, but examples include balls bouncing into stands or hitting objects suspended over fair territory.
  • The signal for a ground rule double is two hands in the air with two fingers up, signaling that the hitter and baserunners should only advance two bases.
  • An automatic double would be considered a two-base hit in any stadium (known as “universal ground rules”). It is still acceptable to refer to an automatic double as a ground rule double.
  • Knowing your surroundings is important for players learning baseball – old stadiums have quirks that can impact gameplay and lead to injuries if not taken into account properly.

Definition of a ground rule double

MLB does not have a specific definition of a ground rule double, but if you piece together other definitions, it becomes clear. The definition of a double is when a hitter puts the ball in play and reaches second base without an error or a defensive attempt on another baserunner.

The MLB rulebook mentions ground rule doubles in its definition of a double, describing the instance of a ground-rule double as “the ball bounces into the stands and all baserunners, including the batter, are awarded two bases.” So where does the phrase “ground rule” come from? 

Each team can have rules that apply to their field that require umpires to award ground rule doubles. The most direct way to explain it is this: a ground rule double is called by an umpire when a player hits a fair ball that becomes unplayable because of a certain part of the field.

You may ask if the ground rules are really that different depending on where you play. It sure does. The history of baseball is filled with rules like this. For example, fans love the iconic ivy at Wrigley Field unless you allow the visiting pitcher to hit the ball in the gap:

How the ground rule double works

For a ground rule double to happen, the following must take place:

  1. The batter must hit a fair ball into play – it does not matter if there are runners on base.
  2. The ball can cross over the outfield wall, but not on the fly, as that would be considered a home run. 
  3. The ball does not have to leave the field of play, but it must be considered unplayable by the umpire.
  4. Once the umpire declares the fair ball “unplayable,” they award the hitter two bases, and any runners on base also get to advance two bases, no more, no less. This rule has cost teams wins and losses, but arguing about it is why we love baseball.

To see what a normal ground rule double looks like during gameplay, watch Shohei Ohtani bounce one over the wall last season:


The impact of ground rule doubles

It is argued that the biggest impact of a ground rule double is that base runners are only allowed to reach two bases instead of three. In many situations, if a hitter hits a double and there is a fast runner on 1st base, then that runner will advance all three bases and score a run. Because of this fact and the fact that a bases-loaded double clears the bases quite often, the ground rule double is more advantageous to the fielding team.

In fact, ground rule doubles can lead to the end of a team’s season. To see an example of this, look at the 2021 ALDS between the Red Sox and the Rays. One of the best analyses of this critical play can be seen below. The play even earned its own name, “The Ground Rule Double at Fenway.” Tampa Bay lost this game and had their season end the following game.

Rules surrounding ground rule doubles

The rules surrounding ground rule doubles are different for each team and each stadium. Below are a few examples that probably make sense if you know this stadium. MLB has authorized these ground rules, so keep that in mind. 

1. Fenway Park (Boston)

A fair ball going through the left-field scoreboard either on a bounce or in flight = ground rule double

2. Oriole Park at Camden Yards (Baltimore)

A thrown or batted ball that remains behind or under the canvas or canvas holder = ground rule double

3. Guaranteed Rate Field (Chicago)

A ball that strikes the 3rd base batter-facing iPad camera (the one facing the pitcher is out of play) and becomes lodged or unplayable = ground rule double

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So, as you can see, the rules are quite different from park to park. All visiting teams are informed of the ground rules, so the best baseball managers will prepare their teams accordingly.


What is an example of a ground rule double?

A basic example (and the most common) is a fly ball hit to the outfield that hits the ground in fair territory and bounces over the outfield wall or into the stands in foul territory. There are also times when a ball can be on the field but completely unplayable. Like this:

How do you signal a ground rule double?

The signal for a ground rule double is to put hands in the air and put two fingers up, signaling that the hitter and baserunners should only advance two bases. Either players or umpires can give the signal. 

Does a ground rule double have to hit the ground?

No, a ball does not have to hit the ground to be ruled a ground rule double. One of the more common examples of this is included in the ground rules at Tropicana Field in Tampa Bay. 

According to Tampa’s ground rules, if a batted ball hits the catwalk, lights, or suspended objects over fair territory, it is called a ground rule double without having to hit the ground. You can see what that looks like below:

What is the difference between a ground rule double and an automatic double?

What is commonly referred to as a ground rule double is, most times, actually an automatic double. What makes them different is that an automatic double would be considered a two-base hit in any stadium (known as “universal ground rules”). 

Ground rule doubles technically only apply to special quirks like catwalks, ivy, or iPads. It is still acceptable to refer to an automatic double as a ground rule double. It has become the more popular and well-known of the two phrases in today’s baseball vernacular. 

Who has had the most ground rule doubles in history?

Since ground-rule doubles are not tracked as individual statistics, it is not possible to tell who had the most ground rule doubles in history, but there are some theories. 

One of the more popular ones is that Babe Ruth is an all-time leader. Prior to 1929, MLB rules stated that if the ball went over the outfield fence, even on a bounce, it was considered a home run. That would have given Ruth more doubles than home runs if it were a statistic. But make no mistake, the Bambino could hit. He consistently put 450-foot moonshots over the wall with no debate.

Another argument is that because ground rule doubles are scored as doubles, when we look at the all-time leaders in doubles, we can assume that players who have recorded over 600 career doubles have the highest probability of having the most ground rule doubles. Some notable players in this group include Hank Aaron, Albert Pujols, Miguel Cabrera, David Ortiz, Pete Rose, and a few others.


For baseball fans and young players learning the game, knowing your surroundings is one of the most important things to understand. It goes to what is called situational awareness. If you played neighborhood baseball in your youth, you probably had certain trees or windows that were considered fair or foul. 

Today’s modern stadiums are no different, and the architects of these cathedrals still find ways to incorporate those same neighborhood quirks. If you look at the old days, it is hard to understand how more injuries didn’t happen because of these quirks. 

Here’s looking at you, Monument Park at Yankee Stadium: