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Monday, May 29, 2006

On bunting a runner to third

Ok, so today I was ripping my hair out watching the Reds' 8th inning. Thanks to a zero-out double by Ryan Freel, we had the tying run on second with nobody out and a very good left-handed hitter in Felipe Lopez at the plate vs. a struggling right-hander in Brandon Lyon. And I proceeded to watch Lopez intentionally get himself out, bunting a scary two-strike sacrifice to advance Freel to third. Griffey was then intentionally walked, Aurilia struck out, and Adam Dunn flew out.

Ok, ignoring the rather awkward nature of Lopez's at-bat (what on earth was he doing taking the second strike and then bunting on the next pitch??), I couldn't understand why the Reds were bunting in this situation. I know this is the classic "small-ball" type of offense, but when you've got a (very fast) runner on second you already have a man in scoring position. Yeah, it's nicer to have him on third, but giving up an out to get him there always seemed like too big a cost to pay for setting up the possibility of a sacrifice fly or run-scoring infield ground ball.

Hoping to write a scathing article proving my point, I pulled up the run expectancy matrix at TangoTiger's website. This matrix was compiled using data from the 1999-2002 seasons and provides the average number of runs teams scored in an inning given each possible combination of baserunners and outs. I compared data on two situations:
  • With a runner on second and nobody out, teams scored an average of 1.189 runs.
  • With a runner on third and one out, the situation we had after Lopez sacrificed Freel over, teams scored an average of 0.983 runs. That's a 17% drop in how many runs you score.
Looks like a bad way to go about your business, eh? Well hold on: as any old-school ball-player will tell you, this maneuver is one you do late in a ballgame to try and score only one run. In the Reds' situation, they were down 4-3 in the bottom of the 8th, and needed that one run to force a tie and avoid losing so they could start focusing on winning (the old "play to tie at home" strategy). Therefore, what really matters in that situation is the probability of scoring a single run, not additional runs beyond the one. To examine this, I looked at our two situations in the next matrix on TangoTiger's website, the Run Frequency Matrix, which gives the probabilities of scoring 0, 1, or more runs in each baserunner/out scenario. Here are the data:
  • With a runner on second and nobody out, teams scored zero runs 36.8% of the time, one run 34.8% of the time, and two or more runs 28.3% of the time.
  • With a runner on third and one out, teams scored zero runs 33.8% of the time, one run 47.8% of the time, and two or more runs 18.3% of the time.
Wow. So it looks like the small-ball guys have a point. While the overall number or runs you'll score after sacrificing a runner to third decreases, the probability that you'll score at all increases from 63.2% to 66.2%. Not a huge increase, but an increase. And, if you have less confidence in the hitter you're asking to sacrifice (in this case, Lopez) than you do in the hitters that follow him (Griffey and Aurilia), then this does turn out to be your best move in that situation.

So I learned something. Apologies to Narron (or was it Dent at that point--I think Jerry had already been tossed from the game) for all those nasty thoughts I was sending his way through the TV.

P.S. The Latin Love Machine has returned!


  1. Great post today, JinAZ. The first thing I thought when Lopez squared to bunt was "uh oh, the bloggers are going to go nuts." But I was okay with playing for one run, especially with the recent offensive struggles. And I was comfortable that Aurilia could get the job done.

    What kills me is that good hitters still try to bunt after they get two strikes on them. Is it possible to get the success rate of bunting with two strikes?

  2. A three per cent increase in a chance to score a run, versus a ten per cent drop in chance to take the lead? I'd rather not bunt, personally. And how much confidence do you really have in Aurilia? Of course, the idea was Griffey would hit a sac fly, but it didn't work. And bunting with two strikes, as Brian said, is a really, really poor percentage move.

  3. Given that most players' success rates with 2 strikes are so low anyway, I usually don't have a problem with guys bunting in that situation. At the very least you can catch a defense unawares.

    Besides, Herm Winningham is awesome.

  4. Thought about this more overnight... one factor I hadn't considered was bunting success rates *period*, much less with two strikes. The probability that you'll fail to score at least one run inreases from 36.8% to 71.7% if the runner is thrown out at third and the bunter is safe at first. That's a staggering difference -- 34.9%. Therefore, unless bunting success is very high (greater than 89% if I'm figuring right), the advantage to trying to move the runner to third evaporates. I haven't been able to find those figures, but I have doubts that the success rate is that high.

    So I think I'm back on the other side of the fence. Don't bunt in that situation. Just go for the hit. A ground ball to the right side will have the same effect anyway, and it might just get through the infield. :) -j

  5. Two more X factors: Defensive errors on the attempted bunt, or Lopez beating it out. Both push the needle slightly back toward "smart," though I have no clue how much.