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Strikebreakers: Inside the Houston Astros’ League Low Strikeout Rate

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The Houston Astros’ best-in-the-majors strikeout rate is helping drive its powerful offense, but not in the way you might think.

MLB: AUG 09 Mariners at Astros Photo by Leslie Plaza Johnson/Icon Sportswire via Getty Images

Getting Rid of the Letter K

This past Labor Day, September 2nd, against the Milwaukee Brewers, Houston Astros outfielder Jake Marisnick struck out to end the top of the tenth inning. With the strikeout, the Astros became the last team in the majors to reach 1,000 strikeouts on the season.

The Houston Astros have the fewest batting strikeouts in baseball, and it is not by accident.

As recently as 2015, Houston had worst strikeout rate in the American League. In 2016, they had the second worst. Then seemingly overnight, the Astros went from the worst to the best. In 2017, they struck out 25% fewer times than in 2016 and had the best strikeout rate in the majors.

Houston Astros Strikeout Rates 2013-2019

YEAR K % AL Rank
YEAR K % AL Rank
2013 25.5% 15th
2014 23.8% 15th
2015 22.9% 15th
2016 23.4% 14th
2017 17.3% 1st
2018 19.5% 2nd
2019 18.3% 1st
(2019 data is thru 9/2/2019)

The dramatic change in strikeout rate was by design. “Power’s exciting, power sells tickets and power wins games, at times,” Astros GM Jeff Luhnow told the New York Times in 2017, “But power usually comes at the expense of rally-killing strikeouts in other instances. It’s not a satisfying brand of baseball, and I don’t think it’s a winning brand of baseball, necessarily, to have 30-home run hitters with 200 strikeouts a year.”

The Astros boasted the second lowest strikeout rate in the majors in 2018, and in the offseason targeted free agent Michael Brantley, whose hitting style was renowned for avoiding strikeouts. Leading the majors again in strikeout rate, the message is clear: the Houston Astros want to put the ball in play.

Except Strikeouts Really Aren’t That Bad

The 2017-2019 Astros offenses have been some of the best offenses the franchise has ever had. This is particularly true of the 2017 and 2019 offenses, whose respective 122 and 123 wRC+’s approach the 126 wRC+ of the legendary 1927 New York Yankees.

Clearly, the precipitous drop in strikeout rate must be the secret to the Astros’ offensive success.

Except that strikeouts really aren’t that bad. They are not the worst thing a batter can do at the plate. By linear weights (values assigned to events estimating their effect on run expectancy), a strikeout is only just barely worse than a groundout or flyout.

Sure, a hitter can’t score a runner from third by striking out, or advance a runner into scoring position, or even challenge the defense into committing an error. But he also can’t hit into a double play, and the Astros lead the majors in that category with 125 through this writing. (Second in the majors in grounding into double plays? The Los Angeles Angels of Anaheim, who also happen to be second in the league in strikeout rate to the Astros.)

The idea that striking out isn’t the worst thing in the world is a concept that has caught on with many other teams. They not only don’t fear striking out, they embrace it for the extra power that it can bring. Record high home run rates and record high strikeout rates have gone hand in hand over the last several years.

Strikeout Context

When you consider all different scenarios of striking out collectively, strikeouts are no worse than any other batted ball out. In 2017, Tangotiger blog broke down the 3 different contexts of strikeouts:

  1. Plate appearances with 2 outs or with the bases empty - In these scenarios, a strikeout is no different than a batted ball out and is equivalent in cost. These constitute 76% of plate appearances.
  2. Plate appearances with < 2 outs, runner on 1st, or runner on 1st and 2nd - In these scenarios, grounding into a double play enters the equation, and a strikeout is LESS costly than a batted ball out. These constitute 15-16% of plate appearances.
  3. Plate appearances with < 2 outs, runner on 3rd, or runner on 2nd with 1st base open – In these scenarios, with first base open, grounding into a double play does not factor in as much, and a strikeout is MORE costly than a batted ball out. (While grounding into a double play remains a possibility with the bases loaded or with runners on first and third, it is outweighed by the possible benefits of a batted ball with a runner on third base.) These constitute 8-9% of plate appearances.

When all three situations are analyzed as a whole, Tangotiger concluded the strikeout is no more or less costly than a batted ball out.

So if the strikeout is no different than any other out, why does it matter so much that the Astros decreased their strikeout rate and put the ball in play more? Is it perhaps that when “Context #3” comes up and the strikeout is more costly, the Astros drop their rate even further?

Not exactly. In situations where strikeouts are more costly, the Astros’ strikeout rate does drop to 17.8%, but that is still within sampling error variance of their overall rate of 18.2%.

In fact, most teams drop their strikeout rate in scenarios where the strikeout is more costly and they do it more markedly than the Astros do. Why aren’t the Astros dropping their strikeout rates in these situations to the same degree other teams are? Based on Luhnow’s expressed desire to be a low strikeout team, the Astros have simply been looking to drop their strikeout rate across the board, and not specifically in one set of situations.

2019 AL Strikeout Rate Splits

Team K% K% when K equal in cost K% when K less costly K% when K more costly Change in K% when K more costly
Team K% K% when K equal in cost K% when K less costly K% when K more costly Change in K% when K more costly
HOU 18.2% 18.4% 17.6% 17.8% -0.4%
LAA 19.5% 20.2% 19.3% 14.4% -5.1%
MIN 20.9% 21.6% 19.9% 16.7% -4.1%
BOS 20.9% 21.3% 20.5% 18.8% -2.1%
OAK 20.9% 21.5% 18.6% 20.1% -0.8%
CLE 21.3% 21.9% 19.2% 19.8% -1.5%
KCR 22.4% 22.8% 20.5% 22.5% 0.0%
NYY 22.6% 24.0% 19.4% 17.0% -5.7%
BAL 23.7% 24.5% 20.5% 21.4% -2.2%
TBR 23.7% 24.0% 22.0% 24.4% 0.7%
TOR 24.2% 24.8% 21.0% 24.8% 0.6%
SEA 25.3% 25.8% 23.5% 23.7% -1.5%
CHW 25.6% 26.7% 22.9% 21.9% -3.7%
TEX 25.8% 26.7% 23.5% 22.0% -3.8%
DET 26.7% 27.2% 25.9% 23.7% -3.0%
(Data through Aug 31, 2019)

When the strikeout is more costly, and you absolutely, positively need to get the ball in play, which of the 2019 AL Postseason Contenders are striking out the least? The Minnesota Twins (16.7%) and the New York Yankees (17.0%) come out ahead of the Astros (17.8%). The Twins drop their strikeout rate 4.1% from their overall rate, and the Yankees drop theirs close to 6 full percentage points. Aaron Judge, Giancarlo Stanton and Gary Sanchez’ New York Yankees, whom baseball fans love to point to as the poster child for the strikeout strategy of “go big or go home”, have a lower strikeout rate when it matters most, than the Houston Astros.

The Secret of Success

So why does it still seem like the Astros’ low strikeout rate is driving their historically great offense? Well, there are more components at play. Not only do the Astros have the fewest strikeouts in the majors, but they also have the most walks. The combination of striking out the least and walking the most points to a team that is seeing the ball and strike zone better than other teams. Simply put, it points to a team of better hitters.

What else is different about the 2017 and 2019 team compared to the 2015 that had the highest strikeout rate in the league? Well, the 2017 and 2019 Astros batted .282 and .274. The 2015 Astros batted .250.

Batting average is no longer the great metric it was once thought to be in evaluating offense, but in this case, it demonstrates something very clearly.

The Houston Astros are not decreasing their strikeout rate by trading strikeouts for batted ball outs. They are trading strikeouts for hits. These hits are not coming from sacrificing power either. The Houston Astros still rank second in the majors in OPS, just .003 behind the Twins. They are having their cake and eating it too.

Batted ball outs are not any better than strikeouts. But hits most definitely are, and you can’t get hits unless you hit the ball.

The Houston Astros aren’t hitting better because of a concerted effort to be a team that strikes out less. They are striking out less because of a concerted effort to be a team that hits better. While that may seem like an obvious distinction, it is one that has been missing from narratives brought up when discussing the Astros’ low strikeout rate.