The infield fly rule is a rule used to prevent a team from letting a pop-up drop in order to get two outs instead of the one that catching the ball would accomplish. It is called when a pop-up is hit on the infield (judgment call by the umpire) and there are less than 2 outs and runners on first and second base, or the bases are loaded. The reason is that a player could let the ball drop and because all of the baserunners return to the bases assuming the ball will be caught, the fielder could presumably throw to two bases for a double play as if it were a ground ball. Once the rule has been called by the umpire (done by pointing to the sky) the batter is out, and the runners can advance at their own risk after tagging up like they would on a fly ball.

The infield fly rule is not in effect with only a runner at first, because if the fielder drops the ball to try to get a double play, the batter has had time to get to first, so the fielder will only get a force out at second, not a double play. If the batter has not had time to get to first, either: (a) it was a line drive, in which case the fielder is entitled to the double play, although as a practical matter, this seldom happens, because the fielder will usually catch the line drive and double off the runner with a throw to first, or (b) the batter is a lazy slob who didnt leg it out, in which case, he deserves to hit into the DP.

The other runners can try to advance at their own risk as they would on any other fly ball. If the ball is caught, the runners must tag up before advancing. If the ball is not caught, there is no need to tag up. The difference for the runner is that since the batter is out, there is no longer a force play and the runner doesn't need to advance, even if the ball is not caught.

Let me get this straight, since there is no need to actually catch the ball, once the umpire calls or signals" infield fly "the baserunner is free to tag up and proceed to the next base at their own peril, though the ball may still be in the air. Right?

These responses are good but there is one little sidenote missing. The infield fly rule doesn't apply to line drives or a bunted ball. There's an additional rule that applies to an intentionally dropped ball including line drives and fly balls when the infield fly rule is not called. This rule states that the batter is out if a defensive player intentionally drops the ball with the intention of gaining a defensive advantage by not catching it. An example is there's a runner on first and a line drive is hit to the shortstop close to second base. The shortstop drops the ball in order to try and turn a double play. This rule differs from the infield fly rule in a number of ways: 1) This rule can apply with a runner on first base or first and third in addition to the force plays listed for the infield fly rule 2)This rule can be called by the umpire after the play occurs. An infield fly rule must be called when the ball is in the air. 3) Once the umpire has made the call, the ball is dead and the base runners must return to their original bases. They cannot advance on the play. An important part of this rule to understand is that the rule doesn't apply if the infielder permits the ball to drop untouched to the ground. So, if the shortstop, in the example above let's the ball hit the ground before fielding it (even though he could have caught it in the air), the rule doesn't apply.

Yes - that's correct about the bunt or line drive. And the fielder must be a infielder - in or around the infield. The call is made when the ball is still in the air. The Infield Fly Rule prevents the infielder from intentionally dropping the ball, then making an easy double play at second and third bases (or at third base and home if the bases are loaded.) Because of the rule, the team at bat will receive one out, not two. There's a complete, illustrated explanation of the Infield Fly Rule at: www.baseballfieldguide.com/infieldfly

Andreas Feininger, a world famous photographer, giving his reason for a successful career, “In every art or craft know how useless unless guided by know why.” Likewise, too many times, we talk baseball rules and come up short on the why. I hope this explanation of why for the Infield Fly Rule will suffice. A two for one sale tends to catch our eye; however, applying the Infield Fly Rule marks “no sale” on this trickery. The baseball rules are designed to protect a team from trickery and/or deceit, but not from stupidity. Therefore, one must know the rules in order to play by the rules. Too many baseball folks overlook reading and knowing Rule 2: Definition of Terms. With Feininger’s admonition of “why” in mind, let us review Rule 2. There are 16 baseball terms, repeat 16 that have a bearing on the why understanding of the Infield Fly Rule. Far too many terms to repeat here, but you have access to online baseball rules. Summary of Infield Fly: --Less than two outs for Infield Fly to be operative. With two out there is no need for trickery. --First base occupied. Rule not in effect; however, double play possible if batter-runner fails to run (remember stupidity?) --First and second base occupied. Rule in effect (double FORCE). Batter out, runners protected, but may advance at their own peril. --Bases full, Rule in effect, however, I prefer not to mention third base. It has been my experience that folks tend to get confused with First and Third bases occupied. .Rule not (repeat not) in effect. Best thing is to refer to a double FORCE (first and second bases occupied) --Letting the batted ball fall untouched. Batter ruled out. Ball is in play for the runners who may advance at their own peril. --Intentionally dropping a batted fly ball. (Rule 6.05 l, that’s L as in love). Batter is out ball is dead. Runners hold their bases. No further play possible. --When a situation arises where you have an intentionally dropped ball and an infield fly situation, on the same play, the infield fly rule takes precedence. Jersey Joe

Anonymous stated it correctly except for one thing. The fly ball does not have to be in the infield. If the catch can be made by an infielder with ordinary effort, the IFR should be called. In fact an outfielder can catch the pop up and the IFR is still in effect. example: Runners on first and second, one out. Batter hits high pop up into short Left field but F6 has plenty of time to move under the ball. At this time you would call "Infield fly, Batter's out". Now the left fielder comes in and calls off the shortstop and makes the catch. Because the SS could have made the play with ordinary effort, the IFR is still in effect. Ask yourself this; If the SS let the ball drop, could the defense have turned a cheap double play? If the answer is "yes" you have an infield fly.