Infield Fly Rule

Question
When an umpire calls the Infield Fly Rule, do the bases have to be loaded OR must there be runners on first AND second base?  If this is correct, why isn't the Infield Fly Rule used when there is only a runner on first base?  Isn't the concept the same?  Thanks so much for your help.  You have always been so helpful in the past and very precise.  John

Answer
John,

There must be either bases loaded or runners on first and second.  The reason it isn't called when there is only a runner on first is that if the batter hustles, there is no chance of a double play.  By the time the pop up comes down, they should be at first.  So there is no incentive to drop the ball.

In some instances (such as when the hitter is very slow and the base runner is fast) the defense may still get an advantage by dropping the ball because they substitute a slow runner at first for a fast runner, but the rulebook doesn't penalize an action like this.

With multiple runners on, a dropped ball could lead to a double play because the runners must hold to their bases.  Then when the ball is dropped on purpose the fielders can just step on one base and throw to the next giving the runners no chance.

Hope this helps!

Brian