August 27, 2014

Statistically Speaking: Is the Bunting Working?

If there’s anything in baseball that will get a crowd (or a Twitter conversation) going, it’s discussion of the merits of the bunt. While philosophies have evolved over the years showing that the visceral call for a batter—more often that not a pitcher—to square around and give the team a productive out isn’t nearly the requirement many fell it is, it is a play that remains firmly in place in the game and in the tactics of many managers.

For the Washington Nationals, the bunt remains a common used weapon, both in the form of the sacrifice bunt (currently tied for third in the National League with 39 sacrifice attempts and tied for ninth with 23 successes, for a 14th best 59% success rate) and the bunt hit (first in the NL, with 19). It’s a tactic that belies the hitting prowess of the team, whose reputation as a lineup full of tough outs and hitters who can crush mistakes has preceded them, but it also one that they have failed to live up to.

Currently scoring runs at a clip (4.07 per game per Baseball Reference) just above league average (4.02 runs per game), it has been the sacrifice bunts and bunt hits that have kept a lineup afloat, as they await the power and scoring surge expected of the lineup.

Have these sac bunts and bunt hits been savvy, or haphazard attempts at generating runs, void of acknowledgement of the situation? Has the bunt helped more than hindered the Nats quest for scoring?

To answer these questions, let’s grab some data and see how the bunt attempts shake out; first, let’s look at the running environment has looked when a hitter has squared to sacrifice or to bunt hit.

Runners n=
—1 1
-1- 7
1– 21
11- 5

It’s a fairly mixed bag, but the 58 situations where bunts have occurred are dominated by the no runners on (noted with a ‘—’ and indicative of an attempt at a bunt hit) and runner on first base (’1–’) situations, with a smattering of other base states, each with a runner in scoring position.

Speaking of bunt hits, who has them and how successful were they?

Player Bunt Hits Runs*
Danny Espinosa 6 2
Anthony Rendon 2 1
Bryce Harper 2 1
Denard Span 4 4
Kevin Frandsen 2 0
Nate McLouth 2 0
Taylor Jordan 1 0

*runs scored via runners put into scoring position by bunt; includes errors

Danny Espinosa leads the way with six bunt hits, with two runs being the result of the bunt, either from his eventual scoring or his putting a runner into scoring position via the bunt. Denard Span’s four bunt hits and four runs following the bunts are nothing to sneeze at, either. Overall, eight runs have been scored via the bunt for a hit for the Nats.

Let’s add sacrifice situations—responsible for six runs scored thus far—and tally up how much of a difference they have meant to the Nats and their run expectancies. Using the tenets of The Book and looking at run expectancies of each of the base-out situations before and after a bunt was attempted (RE change in the table below), we can get an idea of how beneficial the bunt was in improving the chances of the Nats scoring in a given at bat. The more positive the number, the more likely runs were produced:

Situation RE change Runs
Sac -4.8978 6
Hit 4.875 8
Total -0.0228 14

Overall, the Nats are playing a negative-sum game with bunting, actually worsening their scoring chances ever so slightly (-0.0228 run expectancy) by their bunting habits, which has netted then 14 runs, or 4.9 percent of their total runs. Yet, we do see that when hitters are bunting for a hit, the team is in good shape with generating runs.

Of course, the sacrifices are predominantly courtesy of the Nats pitchers; even when you consider that most of your starters will swing the bat just well enough to not have them required to automatically bunt with runners on base, there are still situations where the sacrifice will be called for. For the Nats, it’s been called on 18 times for their starters, with the poor-hitting Tanner Roark leading the pack with seven sacrifice bunt outs.

However, there have been five sacrifice bunt outs made by position players—twice by Kevin Frandsen and once each by Denard Span, Nate McLouth, and Anthony Rendon. These five bunt outs change the run expectancy in a fairly significant fashion, dropping the above -4.8978 run expectancy to just -3.8656, good for just a little over a run’s worth of improvement in run expectancy.

While this isn’t to say that all of the position player bunts would magically turn into positive batted ball results, it does show that preventing hitters from swinging the bat can and will lead to fewer runs; the same could be said for some of the pitching staff as well, in certain situations.

It’s hoped that with the mathematical gymnastics completed, a better appreciation of when and where bunting should occur and who should be doing it was reached. In some ways, the bunt—be it for a hit or for a productive out—is similar to a butter knife. It has a particular purpose that it serves quite well, but just because you can use it for other makeshift purposes, doesn’t mean you should.

Data courtesy of Baseball Savant unless otherwise noted as of 6/17/2014.

Stuart Wallace is a Contributor to District Sports Page. A neuroscientist by day, the Nevada native also moonlights as an Associate Managing Editor for Beyond the Box Score, stats intern at Baseball Prospectus, and a contributor at Camden Depot. A former pitcher, his brief career is sadly highlighted by giving up a lot of home runs to former National Johnny Estrada. You can follow him on Twitter @TClippardsSpecs.


  1. Has any team ever won a MLB division playing .522 baseball or worse? Does any team in the NL east actually want to win the division?

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