Baseball Rules: The Infield Fly Rule

There are runners on first and second base with one out. The batter hits a pop up that will come down in fair territory within a step or two of third base. With the third baseman in position to catch the ball, the runners know they have to stay on or very close to their bases, because if they stray too far, the third baseman can catch the pop up and then throw to one of the bases they left to double them up and end the inning. However, there's also a problem if they stay close to their bases, because in that case the third baseman could purposely let the ball hit the ground without catching it, take it on the bounce, step on third base for one force out, and throw to second base for another force out for the double play to end the inning.

In baseball's early days, this was not just a hypothetical situation. Savvy infielders would catch or drop a pop up depending on whether the base runners stayed close to their bases, and get an easy double play, or occasionally even a triple play.

On the one hand you can say this is simply good strategy. It's not unfair, in the sense that both teams are equally able to pursue the strategy. Yet there was always the feeling that there was something vaguely unsportsmanlike or inappropriate about it, that there shouldn't be an advantage to purposely dropping a pop up.

So in 1895, the Infield Fly Rule was enacted to deal with just this kind of scenario. Let's take a closer look at how it works.

In order for the rule to apply:

1. There must be zero or one out.
2. There must be runners on first and second, or the bases must be loaded.
3. A batted ball must be hit in the air in or near fair territory.
4. The ball must not have been hit as an attempted bunt.
5. The ball must not be a line drive.
6. The ball must be catchable with ordinary effort by an infielder, the pitcher, or the catcher (or an outfielder who for whatever reason had been pulled in to function as an additional infielder).

The invocation of the infield fly rule is a judgment call by an umpire. There will be cases where the arc of the ball is in a gray area between what would normally be considered a pop up and what would normally be considered a line drive, and there obviously will be close calls as far as whether a ball could be caught with ordinary effort.

But if all six of these conditions are met in the opinion of the umpire in the best position to judge, he is to announce "Infield Fly Rule" loud enough to alert the base runners. If he is uncertain whether the ball is coming down in fair or foul territory, he should call out "Infield Fly Rule if fair."

Once the Infield Fly Rule is invoked, its implications are as follows:

1. If the ball is caught, it is played exactly the same as if there were no Infield Fly Rule. (This remains the case even if someone who was not playing in the infield catches it, such as if an outfielder charges in while the ball is in the air and the infielder gives way to him and lets him catch it.)

2. If the ball is not caught and ends up in foul territory (whether it lands there and stays there, or lands in fair territory and rolls foul), it is played exactly the same as if there were no Infield Fly Rule. It is simply a foul ball.

3. If the ball is not caught and ends up in fair territory (whether it lands there and stays there, or lands in foul territory and rolls fair), this is where the Infield Fly Rule makes a difference. The batter is declared out. The runners cannot be doubled up by throwing to the base they left; they may attempt to advance without tagging their base as they would normally have to do on a ball that's caught in the air. There is also no potential force out of the runners.

So once the Infield Fly Rule is invoked, the batter has no reason to continue running to first. He will be out regardless (or it will be a foul ball). On the other hand, the runners might as well go all out to advance as many bases as they can, on the small chance that the ball is not caught.

Incidentally, the Infield Fly Rule has not completely eliminated cases where it is advantageous to refrain from catching a batted ball for an out.

Consider, for one, an instance where there is a man on third with one out, and a long foul ball is hit into the corner. The outfielder might well choose to just let it drop as a foul ball, if getting the out is not worth allowing the man at third to tag up and score.

Or consider an infield pop up with a man at first and one out, where the man at first is a very fast and skilled base runner, while the batter is a very slow, lumbering base runner. (The Infield Fly Rule does not come into play, because Condition #2 above is not met.) The infielder might well let the ball drop and get the force out at second. They'll still get one out on the play regardless, but this way the base runner will now be the very slow player.

Sources:

"Official Rules: 2.00 Definition of Terms." MLB.com.
"What is the Infield Fly Rule?" Wise Geek.