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Bunting the Runner Over in Extras

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The math tells us that bunting is counterproductive. But with the new extra-innings rule starting each frame with a runner on second, is there a role for bunting again in major league baseball?

MLB: JUL 12 Astros Summer Camp Photo by Juan DeLeon/Icon Sportswire via Getty Images

We’ve all seen “Moneyball”. We’ve all seen Josh Reddick’s shirt teaching you how to bunt.

We get it. Unless you’re a pitcher, bunting is bad. And with the universal DH, pitchers don’t even need to come to the plate anymore.

For the most part, that’s correct. Bunting is counterproductive. Consider bunting a runner from first to second:

  • Expected Runs in an inning with a runner on 1st and 0 outs: 0.85 runs
  • Expected Runs in an inning with a runner on 2nd and 1 out: 0.67 runs

There’s no reason for you to make this trade and end up with a lower run expectancy.

The run expectancy penalty is similar if you are bunting a runner from second to third:

  • Expected Runs in an inning with a runner on 2nd and 0 outs: 1.10 runs
  • Expected Runs in an inning with a runner on 3rd and 1 out: 0.93 runs

Bunting the runner over costs you about 0.17 runs.

So in the bottom of the twelfth inning of last night’s game between the Houston Astros and the Los Angeles Dodgers, with the score tied 2-2, and the Astros beginning the inning with Kyle Tucker batting and George Springer on second (thanks to the new extra innings rule), the Astros didn’t bunt.

But maybe they should have.

Yes, the numbers listed above do suggest that you will score more runs with a 0 out/Runner on 2nd situation than a 1 out/Runner on 3rd situation. But in the bottom of extra innings, there is no difference between scoring 1 run, 2 runs, 3 runs, or 99 runs. Any of those will win the game in a walk-off.

The only thing you are trying to avoid is coming away with 0 runs.

  • Chance of 0 runs in the inning with a runner on 2nd and 0 outs: 39.1%
  • Chance of 0 runs in the inning with a runner on 3rd and 1 out: 35.4%

If you have the choice between a runner on 3rd with 1 out versus a runner on 2nd with 0 outs, if it’s a tie game in the bottom of extras, you should want the runner on third, even if it costs you an out.

The Astros didn’t do that. The Dodgers also didn’t do that, but it’s a different scenario for a visiting team batting in the top half of extras. The visiting team does not know how many runs they will need to score to win the game, so it makes sense for them to try to score as many runs as possible. For the Dodgers, bunting the runner over was decidedly not advantageous.

This, of course, assumes that all your sacrifice bunt attempts will be successful, which they aren’t. On average, they’re successful about 70-80% of the time. When they’re not successful, the chance of 0 runs jumps by about 20%.

  • Chance of 0 runs in the inning with a runner on 2nd with 1 out: 60.2%

MLB teams don’t practice bunting as much as they used to. Not in games, not in batting practice. Why should they? The numbers suggest they don’t help. They’ve seen the T-shirt.

But suppose a team was able to increase the sacrifice bunt success rate to 85% rather than 70-80%. That is certainly an achievable goal with practice. Then 85% of the time, they are trading a runner on 2nd with 0 outs for a runner on 3rd with 1 out. The other 15%, they are typically going from 0 outs with a runner on second to 1 out with that runner still on second. (Very rarely, to 2 outs with no runners if the bunt results in a double play. This is much less likely with first base open, though.) If you weight the 85% and the 15% resultant situations, the chances of coming away with 0 runs after a sacrifice bunt attempt in extras (with 85% success rate) is. . . 39.1%. The same exact percentage as if you didn’t bother bunting at all.

This assumes all batters at the plate are created equal though, and they are not.

In the bottom of the 10th, Jose Altuve led off the frame with Kyle Tucker on 2nd. Altuve is a proven, accomplished hitter. The run expectancy is probably going to be a little higher if you allow him to hit, rather than bunt.

But in the bottom of the 12th, Tucker led off. Is Kyle Tucker’s bat so valuable that the Astros should forgo the bunt attempt?

Probably not. But Tucker’s sacrifice bunt success rate also probably isn’t 85%. He’s had 1 sacrifice bunt in the last 4 years of his professional career. It could be though, with practice.

1 out of every 13.1 major league baseball games goes to extra innings. A team will have on average between 11 and 12 extra inning games in a 162 game season. This situation is going to come up frequently.

With the new extra-innings rules, there’s a role for bunting again in the major leagues.

Time to square up.

(Run expectancy values and odds from gregstoll.com)