What Strikeouts Have Taken from Baseball

It shouldn’t be news that strikeouts have increased at a pretty alarming pace over the last decade. From the end of the last strike through 2007, the league-wide strikeout rate was pretty steady, averaging 16.7%. That is, roughly one in every six plate appearances ended in a strikeout. Over the last decade, the average has reached nearly 20%, including a high of 21.6% this year. Now, more than one in every five plate appearances ends in a strikeout. A strikeout is now 30% more likely than it was a little over a decade ago.

This is a problem with many possible solutions: raising the bottom of the strike zone; lowering the mound; or, my personal favorite, expanding the league. This piece isn’t prescriptive, however. The focus of this piece is to show exactly what the strikeout has replaced, and it isn’t actually all bad.

Because I started this piece by doing some research on the home-run record, we will focus here on the year 2000 as it compares to the present. That season represents what was probably the height of the PED era; it was also the season responsible for the league-wide high in home runs until this year. Because the power numbers between the two periods are similar, a comparison of the seasons creates an interesting vantage point from which to view the role of the strikeout.

Generally, we imagine that players have to sacrifice contact for power. It’s notable, then, that the power numbers of today are equivalent those of the 2000 season even though players are striking out 30% more often now than they did back then. To provide some background, here are some standard numbers from 2000 and 2017.

As the 20-point difference in wOBA illustrates, overall offensive levels were higher back in 2000. The ISO and BABIP figures are all roughly similar. When a batter hits a ball in play, that batted ball is just as likely to become a hit as it was before. When it lands fair, it’s leading to roughly the same amount of extra bases. All that’s basically the same.

In terms of differences, one finds that this year’s walk rate is a bit lower than in 2000. That has some influence on run scoring, but not at all to the same degree that the increase in strikeout rate has. In effect, 5% of potentially positive plate appearances have been turned into strikeouts. That’s significant. However, while the main complaint about strikeouts is that they lead to fewer balls in play, it isn’t accurate to suggest that every extra strikeout has actually had that effect.

We can take a deeper look and see exactly what events those strikeouts have replaced. The table below shows the percentage of plate appearances that have ended in particular outcomes between the two seasons.

While strikeouts have increased by five percentage points since 2000, hits have decreased by less than one percentage point. We’re still seeing almost as many hits as we saw before. One positive byproduct of teams getting smarter over the past 15 years is that we are seeing fewer intentional walks and fewer sacrifice bunts. While half a percent of plate appearances might not seem like much, if we’ve taken 10% of the current increase in strikeouts in place of intentional walks and sacrifice bunts, that seems like a positive 10%.

There are a couple types of events missing from the table above, notably most outs in play as well as outs due to caught stealing. Even though caught stealings aren’t recorded as plate appearances, we can express them as a percentage of plate appearances to get an idea of their frequency. In 2000, there were 1323 caught stealings, which was 0.7% of plate appearances. This season, there have been just 872 caught stealings, which is 0.5% of plate appearances. I would also add that grounding into a double play adds an extra out around 2% of plate appearances, but that is virtually unchanged from 2000. I would also note that, unfortunately, hit-by-pitches are up slightly from 2000 by roughly one-tenth of 1%.

The graph below takes the above information and divides the added strikeouts in to portions based on what has been taken away in the game compared to 2000.

To get a sense of the consequences of an increased strikeout rate, we can use the graph here to identify which trends have been positives and which items have been negatives. Events that create action are generally regarded as a net positive for the game. Unfortunately, the two outcomes that have been replaced most frequently by the strikeout are two that lead to action: ball-in-play outs and hits. Add in sacrifice flies and that makes up for roughly 70% of the losses due to strikeouts. That’s not great.

On the other hand, getting rid of walks isn’t a big deal, as strikeouts tend to offer more action than walks. Bunts can be exciting, but sacrifice bunts take the bat out of a hitter’s hands. It isn’t as though the batter is trying for a hit in these scenarios. I’d rather see a pitcher swing than try to bunt if we are talking about pure aesthetics. A runner caught stealing is exciting, but if the goal is to put more balls in play, then having fewer players — particularly players not good at it — steal is probably a net benefit for the game. Intentional walks are no fun even if they take less time now than they did a few years back.

Increased strikeouts in the game isn’t a positive. While hitters might be hitting the ball farther than they used to, the homer trend is somewhat recent while strikeouts have been on the rise for some time. The increase in fly balls seems more likely a response to the increasing dominance of pitchers and not necessarily a permanent evolution. It’s important to note that not all that five-point increase in strikeouts has taken away desirable elements of the game, as some of the events that have been pushed out are even less desirable than strikeouts. This isn’t to say that fewer bunts and intentional walks wouldn’t have happened without an increase in strikeouts, but in terms of desirable outcomes, MLB is not suffering quite as big of a loss as it might seem. Fewer strikeouts along with fewer walks and bunts would be even better, and that should be the goal, though continued debate is likely needed on how to accomplish those aims.