An INFIELD FLY is a fair fly ball (not including a line drive nor an attempted bunt) which can be caught by an infielder with ordinary effort, when first and second, or first, second and third bases are occupied, before two are out. The pitcher, catcher and any outfielder who stations himself in the infield on the play shall be considered infielders for the purpose of this rule.
When it seems apparent that a batted ball will be an Infield Fly, the umpire shall immediately declare “Infield Fly” for the benefit of the runners. If the ball is near the baselines, the umpire shall declare “Infield Fly, if Fair.”
The ball is alive and runners may advance at the risk of the ball being caught, or retouch and advance after the ball is touched, the same as on any fly ball. If the hit becomes a foul ball, it is treated the same as any foul.
If a declared Infield Fly is allowed to fall untouched to the ground, and bounces foul before passing first or third base, it is a foul ball. If a declared Infield Fly falls untouched to the ground outside the baseline, and bounces fair before passing first or third base, it is an Infield Fly.
Rule 2.00 (Infield Fly) Comment: On the infield fly rule the umpire is to rule whether the ball could ordinarily have been handled by an infielder—not by some arbitrary limitation such as the grass, or the base lines. The umpire must rule also that a ball is an infield fly, even if handled by an outfielder, if, in the umpire’s judgment, the ball could have been as easily handled by an infielder. The infield fly is in no sense to be considered an appeal play. The umpire’s judgment must govern, and the decision should be made immediately.
When an infield fly rule is called, runners may advance at their own risk. If on an infield fly rule, the infielder intentionally drops a fair ball, the ball remains in play despite the provisions of Rule 6.05(l). The infield fly rule takes precedence.
Once the infield fly is called, the batter is immediately out. Runners may advance at their own risk, but because the runners do not legally lose the "right to occupy a base by reason of the batter becoming a runner," there is no force play out and runners must be tagged. (see Rule 2.00 FORCE PLAY)
Bases loaded, one out. Batter hits a fair fly ball within the infield that can be caught with ordinary effort. The umpire crew correctly identifies this as an infield fly. The defense does not catch the fly ball and F5 steps on home plate, but does not tag R3 who crosses the plate. R3 scores because this is not a force out. The batter is out.
In the video below the offense becomes confused when a declared infield fly is dropped. R1, R2, one out. Batter hits a fly ball that is declared an infield fly. F4 throws to F6 who tags the bag, however there is no force play. R1 wanders off the bag and heads to the dugout and is tagged for the third out.
Infield fly not called, double play results
A bunted ball cannot be an infield fly
The term "ordinary effort" is defined. [Rule 2.00 ORDINARY EFFORT]
If an infield fly is improperly called due to a lack of conditions [wrong configuration of the runners, two outs, or a pop up resulting from a bunt], the batter is not out. The payers are expected to know that the infield fly has been improperly called. [J/R]
If an infield fly is not called due to umpire error in judgment, it is not an infield fly. However, the umpires should not allow a double play that the infield fly rule was intended to prevent. [J/R]
The infield fly rule supersedes the intentionally dropped ball rule and the ball remains alive. To illustrate, R1 and R2, one out. Batter hits a pop up on the infield and the infield fly rule is invoked by the umpires. The clever shortstop decides to have some fun and guides the ball to the ground with his glove. According to the rules, the ball is live and the batter is out on the infield fly. Now what will the runners do?