MLB: How baseball has changed over the decade

DENVER, CO - AUGUST 05: The Colorado Rockies infield employ the infield shift as they defend against the Seattle Mariners during interleague play at Coors Field on August 5, 2015 in Denver, Colorado. The Rockies defeated the Mariners 7-5 in 11 innings. (Photo by Doug Pensinger/Getty Images)
DENVER, CO - AUGUST 05: The Colorado Rockies infield employ the infield shift as they defend against the Seattle Mariners during interleague play at Coors Field on August 5, 2015 in Denver, Colorado. The Rockies defeated the Mariners 7-5 in 11 innings. (Photo by Doug Pensinger/Getty Images)
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(Photo by Michael Reaves/Getty Images)
(Photo by Michael Reaves/Getty Images)

The whiff

It’s been more than 15 years since a researcher named Voros McCracken unveiled the concept of the Three True Outcomes, those events that were totally and utterly beyond the realm of luck. The three – home runs, strikeouts and bases on balls — had always been recognized independently for their importance, but they soon entered the analysts’ lexicons as a collective.

Over the past decade, teams have focused on the run-scoring importance of the Three True Outcomes to such an extent that in 2019 teams averaged 2,183 “true outcomes” per season, an 18.58 percent increase from one decade earlier.

The increase in home runs has already been documented. But the increased acceptance of strikeouts is even more dramatic. In 2009, teams struck out an average of 1,120 times per season. By the end of this season, that average had catapulted to 1,427 strikeouts per team, a 27.5 percent increase.

One decade ago, teams were only beginning to develop a tolerance for the K. In 2008, Mark Reynolds became the first player in history to strike out 200 times in a single season, and one year later he raised his record to 223. At that time, even the 190 strikeout barrier had been breached just seven times, all of those occurring since 2004.

Today, Reynolds’ 223 remains the major league record, but it is decidedly under siege. In the past decade, 23 players have fanned at least 190 times, and 11 have done so at least 200 times.
Nine times in the past decade, the major league record for strikeouts per team has been broken. The only exception was 2015, when teams averaged 1,248 strikeouts, exactly matching their 2014 average performance.

The change over the decade amounts to 283 strikeouts per team. To find a similar amount of change over time, you have to reach back from 2009 all the way to 1983, more than a quarter century into the game’s past.