It was Monday, April 21^st, 2014.  Michael Choice of the Texas Rangers started running when the pitcher lifted his leg.  However, the catcher stood out of his crouch at about the same time and slid away from the right-handed-hitting Elvis Andrus on a called pitch out.  As the ball crossed the plate, Andrus jumped and lunged simultaneously in his best attempt to make contact but his swing looked more like a bad landing on a less-than-perfect triple axel.  Andrus had one objective with that swing: to protect the runner.

For those unfamiliar, protecting the runner is the ideology that swinging through a pitch when a runner is stealing makes it harder for the catcher to throw the base stealer out.  The swing is thought to be a distraction and makes it so the catcher can’t cheat upwards without getting hit.  Although this is a largely agreed upon fact among those involved in baseball, I wanted to see if it was beneficial or not.

Using the data collected here at Baseball Info Solutions, I compiled all stolen base attempts of second base from the 2013 season where a catcher pop time was recorded (the time it takes from when the pitch is caught to when the ball gets to the fielder covering second base).  This eliminates stolen base attempts where the catcher didn’t have a chance to throw the runner out.  It also removes the instances where the catcher made an extremely poor throw.

The table below shows the aggregate totals from the 2013 season.

It is easy to see that runners were caught stealing less frequently when the batter didn’t swing compared to when he swung.  If swinging makes it more difficult for a catcher to throw a runner out, why were catchers more successful in these situations?  One possibility is that the pitches that batters choose not to swing at are so far out of the strike zone that it is tougher for the catcher to get off a good throw.  However, this would mean an unlikely percentage of pitches on stolen base attempts are out of the strike zone.  It is likely that there is a different reason behind these statistics.

While these results were somewhat surprising, this is not comparing apples to apples here (more like Miggy to Ellsbury).  Out of the 2048 stolen base attempts where we had a valid catcher pop time, there were 1765 attempts where we also had a stolen base time.

Runners were caught stealing way more often when the batter swung because the hitter knew they needed to protect the runner for a reason: he was slow.  Many times these slower runners (on average 0.08 seconds slower) were likely put in motion due to a hit and run where a batter was forced to swing or in a 3-2 count where the manager didn’t think the batter would strike out.  However, when the batter swung and missed the slower runner was usually left out to dry.

So does swinging actually help protect the runner?  The easiest way to judge this was to look at catcher pop times.

This means the average catcher pop time is 0.04 seconds longer when the batter swings compared to when the batter takes.  In order to put this amount of time in perspective, Eugene Coleman of the University of Houston found that the average major league ballplayer ran 24 feet per second.  Using this number (it doesn’t take into account sliding but it’s a good baseline), having 0.04 more seconds means the average major leaguer can cover 11.52 more inches of ground.  That difference in pop time means the potential base stealer can almost travel an extra foot!  This is significant because many plays (and stolen bases) are decided within a foot of the base.

This led to the conclusion that swinging does help protect the runner.  On average it takes the catcher more time to get the ball to second base when the batter swings compared to when he doesn’t.  However, it should be observed that many times the batter took the pitch when a runner was stealing.  There are a variety of possible reasons for this revolving around the idea that there is a certain amount of risk a player takes by swinging.  One reason they would take is that they don’t want to risk messing up a potential stolen base and/or good jump by fouling the pitch off.  Another reason they might take is that they don’t want to swing at a ball and give the pitcher a free strike.  After all, the runners that steal are expected to have the speed to be successful.

So should the batter swing when the runner is moving?  That is not for me to decide, but you might want to ask Michael Choice.  After all, he was safe.