A look at strikeout trends across affiliated baseball

Major League Baseball players are striking out more frequently than ever before. Not only is that statement true today, but it’s also been true for each of the last seven years. The Major League strikeout rate has been trending upwards for a while now, having increased in 25 of the last 29 years. Other trends, such as walks, and runs per game have ebbed and flowed over this time, but the strikeouts have continued to mount.  The strikeout trend has really picked up steam in the last decade or so, with the league-wide rate jumping from 16.4% in 2003 to 20.4% this year.


There are many theories as to what’s causing all of these strikeouts, ranging from harder-throwing pitchers to an increased patience from hitters. Whatever the cause, this trend has started to grab the attention of baseball fans and analysts, many of whom feel soaring strikeout numbers are bad for the game. Most notably, Rob Neyer of Fox Sports has labeled the trend “the strikeout scourge”. Interestingly, this scourge hasn’t been quite as widespread across the various minor league levels. Since 2003, strikeouts in triple-A have increased about 85% as fast as in the big leagues. But in rookie ball, they’ve grown at a much slower rate, and have actually been on the decline for the last few seasons.

K Indexed to 03

The further you look down the minor league ladder, the less strikeouts are increasing. The trend here is pretty clear… Or is it?

The graph above makes it seem like strikeouts have risen modestly in the low minors, but have run rampant at baseball’s highest levels. Framed another way, the MLB strikeout rate isn’t spiraling out of control. Instead, it’s merely caught up with the rest of affiliated baseball, which has been sporting higher rates for decades.

K Affiliated

K Minors and Majors
Note: Does not include stats from the Dominican Summer League

We might be looking at the strikeout scourge the wrong way. The MLB has seen a spike in strikeouts in recent years, but perhaps these years aren’t the outliers. Major League Baseball itself might have been the outlier in that it wasn’t converging with what was going on everywhere else. Up until 2012, the major league strikeout rate had never surpassed the minor league rate, but for the first time in history, the average major league hitter is striking out frequently than the average minor leaguer. Now that the MLB has caught up with the rest of affiliated baseball, it will be interesting to see if the “strikeout scourge” finally slows down, or continues escalating at the pace we’ve seen over the last decade.

About Chris

Chris works in economic development by day, but spends most of his nights thinking about baseball. He writes for Pinstripe Pundits, and is an occasional user of the twitter machine: @_chris_mitchell
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