Following up on my previous post about the infield fly rule, lets get to the bottom of the zero-sum game that ensues when there is a fly ball in the infield.  Let’s suppose the bases are loaded and there are no outs.

The infield fly rule is an artificial rule under which the batter is immediately called out and the runners are free to remain standing on base.  Wikipedia recounts the usual rationale:

This rule was introduced in 1895 in response to infielders’ intentionally dropping pop-ups to get multiple outs by forcing out the runners on base, who were pinned near their bases while the ball was in the air.[2] For example, with runners on first and second and fewer than two outs, a pop fly is hit to the third baseman. He intentionally allows the fly ball to drop, picks it up, touches third and then throws to second for a double play. Without the Infield Fly Rule it would be an easy double play because both runners will tag up on their bases expecting the ball to be caught.

I would argue (as do commenters to my previous post) that there is no reason to prevent a double play from this situation, especially because it involves some strategic behavior by the defense and this is to be admired, not forbidden.  But aren’t we jumping to conclusions here?  Will the runners really just stand there and allow themselves to be doubled-up?

First of all, if there is going to be a double play, the offense can at least ensure that the runners remaining on base will be in scoring position.  For example, suppose the runner on second runs to third base and stands there.  And the batter runs to first base and stands there.  The other runners stay put.  Never mind that there will now be two runners standing on first and third base, this is not illegal per se.  And in any case, the runner can stop just short of the base poised to step on it safely when the need arises.  What can the defense do now?

If the ball is allowed to drop, there will be a force out of the runners on third and first.  A double play.  But the end result is runners on first and third.  Better than runners on first and second which would result if the three runners stayed on their bases.  And careful play is required by the defense.  If the force is taken first at second base, then this nullifies the force on the remaining runners and the runner on third would be put out only by a run-down, a complicated play that demands execution by the defense.  The runner could easily score in this situation.

If on the other hand the ball is caught, then the runer on second will be put out as he is off base.  Another double play but again leaving runners on first and third.

So the offense can certainly do better than a simplistic analysis suggests.  They could allow the double play but ensure that no matter what the defense does, they will be left with runners on first and third.

But, in fact they can do even better than that.  The optimal strategy turns out to be even simpler and avoids the double play altogether.  It is based on rule 7.08H:  (I am referring to the official rules of Major League Baseball here, especially section 7)

A runner is out when … He passes a preceding runner before such runner is out

According to this rule, the batter can run to first base and stand there.  All other base runners stay where they are.  Now, a naive analysis suggestst that the fielder can get a triple play by allowing the ball to fall to the ground and using the force play at home, third, and second.  But the offense needn’t allow this.  The moment the ball touches the ground, the batter can advance toward second base, passing the runner who is standing on first and causing himself, the batter, to be called out.  One out, and the only out because according to rule 7.08C, this nullifies the force so that all the baserunners can stay where they are, leaving the bases loaded:

if a following runner is put out on a force play, the force is removed and the runner must be tagged to be put out.

Given this option, the fielder can do no better than catch the ball, leaving the bases loaded.  No double play.  The same outcome as if the infield fly were called. So the designers of the infield fly rule were game theorists.  They figured out what would happen with best play and they just cut to the chase.

But just because best play leads to this outcome doesnt mean that we shouldn’t require the players to play it out.  When one team is heavily favored, we don’t call the game for the favorite just because we know that with best play they will win.  To quote a famous baseball adage “that’s why they play the game.” The same should be true for infield flies.  There’s a lot that both sides could get wrong.

As a final note, let me call your attention to the following, perhaps overlooked but clearly very important rule, rule 7.08I.  I don’t think that the strategy I propose runs afoul of this rule, but before using the strategy a team should make certain of this.  We cannot make a travesty of our national pastime:

7.08(i)  A runner is out  when … After he has acquired legal possession of a base, he runs the bases in reverse order  for the purpose of confusing the defense or making a travesty of the game. The  umpire shall immediately call “Time” and declare the runner out;