THE BOOK--Playing The Percentages In Baseball

Monday, September 05, 2011

Re-examining the sac bunt by a pitcher with 1 out and runners on 1st and 3rd

Last night, in the PHI/FLO game, Anibal Sanchez was asked to lay down a sac bunt with runners on 1st and 3rd and 1 out in the second or third inning.  No one batted an eyelash (but me). You see this all the time.  It is SOP.

In The Book, in the chapter on sac bunting (if you haven’t read it, what the heck are you waiting for?), we say that a pitcher should rarely bunt with runners on 1 and 3 and 1 out.  To me, that makes perfect intuitive sense, even from the standpoint of a manager, media analyst, fan etc.  By sacrificing, you give up most opportunities for a run to score on that play (via a hit, sac fly, non-DP ground out) and you give up an opportunity for a walk, even though that rarely occurs.  In exchange, you only move a runner from first to second, which is not that valuable when giving up an out when there is already 1 out (we are going to assume that a sac bunt means one runner advances and the batter is out), which is why a position player, even a poor-hitting one, never bunts with a runner on first and 1 out.  In fact, the average RE (using the 99-03 NL run environment) for runners on 1st and 3rd and 2 outs is .509 and with 2nd and 3rd, it is .574, a pick up of only .065 runs.  So a bunt is not THAT much better than a K or other out that does not advance the runner.

Of course, the manager is scared to death of a DP to end the inning.  How often does that happen?  Well, about half of all ground ball outs by pitchers with a runner on 1st and less than 2 outs are DP’s.  About 30% of a pitcher’s PA end in a ground out, so about 15% of the time, they hit into a GDP.  So basically in exchange for moving the runner up at first and avoiding an inning ending DP around 15% of the time, they give up the chance for a walk, hit, sacrifice fly (and of course an ROE, but that can happen with a bunt also), or a ground out where the runner scores.  Again, this doesn’t seem to me to be a fair exchange.  And The Book says that it is not even close.

Let’s look at the data again - roughly.

We’ll assume that the “successful” sacrifice results in runners on 2 and 3 and 2 outs, or an RE of .574.

What happens if the pitcher swings away? 

First we’ll look at all the positive events.  Here are the frequencies and the resultant RE plus any runs that score:

S .125 1.924 (I am conservatively assuming that the runner on 1st only advances 1 base)
D .019 2.404 (I am assuming, again, quite conservatively, that only one run scores)
T .0013 2.985
HR .0013 3.286
BB .034 1.553
ROE .0075 1.924 (again, assuming runners advance only one base)
SF .058 1.239
Ground out, no DP, runner scores: .105 1.287 (I am assuming that 2/3 of the time, runner scores, and 1/3 of the time, he gets thrown out at home.  I am also assuming that half the time the runner on first advances.)

Now, the negative results:

DP (GDP and other DP, including runner thrown out at home on a fly ball out) .163 0
K .348 .509
Fly out and no runners advance .058 .509
LD out and no runners advance .03 .509
Ground out and runner gets thrown out at home (1/3 of all non-DP ground outs) .052 .437

If we add all these RE up, we get: .741

So, as we suspected, it is not even close!  You are at least (I made lots of conservative assumptions, I think) .20 runs better off not attempting a sac bunt with an average hitting pitcher and runners on 1 and 3 and 1 out.  According to The Book, when pitchers did not sacrifice in that situation, an average of .962 runs were scored, much larger than our expected .741. That is likely because these are the better hitting pitchers, the defense was probably somewhat surprised (resulting in more hits), and the hitting environment was probably high as well.

So how much does this egregious mistake cost teams?  It looks like managers actually bunt around half the time in these situations and that occurs around 1.5 time per team (in the NL) per year.  That is a cost of at least .3 runs per year, probably closer to .4 or .5.  Not much, but still, in the scheme of things, it is a lot. Given that a win costs around 4 million dollars, a manager should be fined $40,000 dollars every time he asks his pitcher to bunt with 1 out and runners on 1 and 3!