In baseball, the infield fly rule is a special case designed to prevent the defense from gaining an "unfair" double play by intentionally allowing an easy fly ball to drop to the ground. An infield fly is a fair fly ball that can be caught by an infielder with ordinary effort, when: A view of the playing field at Busch Stadium in Saint Louis, Missouri. ... After stepping on second base, the fielder throws to first to complete a double play In baseball, a double play (denoted on statistics sheets by DP) is the act of making two outs during the same continuous playing action. ... In baseball, a fair ball is a batted ball that has not yet become a foul ball, and that. ... An infielder is a baseball player who plays on the infield, the dirt portion of a baseball diamond between first base and third base. ...

• A force play exists at third base (i.e., runners are on first and second, or bases are loaded); and
• there are fewer than two outs in the inning.

For the purposes of declaring a ball an infield fly, the pitcher, catcher, any outfielders who began the play in the infield, and the infielders themselves are considered "infielders". Additionally, even if an outfielder comes in to field a ball, if an infielder could have fielded the ball just as easily, the ball should be deemed an infield fly. In baseball, a force play or force out, referred to as a force when the possibility of such a play exists, is a situation when a baserunner is compelled to vacate his time-of-pitch base because the batter became a runner. ... The position of the third baseman A third baseman, abbreviated 3B, is the player in the sport of baseball whose responsibility is to defend the area nearest to third base, the third of four bases a baserunner must touch in a counterclockwise succession in order to score a run. ... In baseball, an out occurs when the defensive team effects any of a number of different events, and the umpire rules a batter or baserunner out. ...

The determination of the effort needed for a fielder to catch a ball relies solely on the umpire's judgment. Umpires are generally taught that if a fielder is comfortably positioned under a high fly ball, it is probably catchable with ordinary effort. Wind or sunlight can affect this judgment, and the umpire may use his discretion in making this call. Home plate umpire Gary Darling signals that the last pitch was a strike In baseball, the umpire is the person charged with officiating the game, including beginning and ending the game, enforcing the rules of the game and the grounds, making judgment calls on plays, and meting out discipline. ...

According to most baseball rule books, the umpire should signal that a ball is an infield fly before the ball lands by calling "Infield Fly" (or if the ball is near foul territory, "Infield Fly, if fair"). However, in practice, some umpires will signal this by simply pointing into the air, and some do not offer any signal until after the play, which can surprise some players who were unaware of the game situation. Umpires will generally proceed to call the batter out after calling an infield fly, as is necessitated by the rules.

The infield fly rule, generally found under Infield Fly in Rule 2 (Definitions) of most baseball rules books, prescribes the following results when an infield fly occurs: Baseball around the world is played under three major rules codes, which differ only slightly. ...

• The batter is automatically out (eliminating force plays at all bases), even if the ball is not caught; and
• runners may attempt to advance at their own risk.

This rule was introduced in 1895, in response to infielders intentionally dropping pop-ups in order to get multiple outs by forcing out the runners on base, who were pinned to their bases while the ball was in the air. 1895 was a common year starting on Tuesday (see link for calendar). ...

Any alleged error in the judgment of the umpire as to whether the ball was catchable with ordinary effort cannot be overturned. However, should the umpire be in error on whether the infield fly rule is in effect, the situation can be rectified. The current understanding in the umpiring community is that the players are expected to know what an infield fly is, irrespective of the umpire's call of the infield fly. If there is no force play at third, or there are two outs, and an umpire calls "infield fly", he is obviously mistaken; the batter is not out and runners are still forced to advance regardless of the umpire's call. Conversely, if there are runners on first and second and fewer than two outs, yet the umpire, thinking the situation is otherwise, neglects to call an obvious infield fly, the batter will be out and the runners will not be forced. Of course, these situations require that the umpire admit to his mistake and correct the problem afterward.

Misconceptions

Participants and fans often misunderstand the infield fly rule. An infield fly cannot occur with a runner on first only. Also, an infield fly does not affect baserunners other than the batter. Just like any other fly ball, if an infield fly is caught, runners must touch (or tag up) their time-of-pitch base before attempting to advance; if an infield fly is not caught, no tag up is required. In baseball, a runner must tag up if a batted ball is caught in flight. ... In baseball, the time of pitch is that instant when the pitcher has begun his pitching motion and, by the rules, has committed himself to throwing the pitch. ...

The infield fly rule cannot be invoked on line drives or bunts. In all situations where the infield fly rule does not apply, a different rule prevents fielders from touching a catchable ball and dropping it intentionally, in an attempt to turn a double play.