How can first pitch strikes be used to analyze hitters?

Any pitcher at any level of competitive baseball has undoubtedly heard the phrase: get ahead in the count. Nothing drives pitching coaches crazy like pitchers who fall behind against hitters and give up walks or extra base hits because of it. The importance of getting ahead in the count is actually measurable in Major League Baseball. In 2016, hitters had a .272/.383/.458 slash line through a 1-0 count, compared to .226/.268/.355 through a 0-1 count.

As a result, a pitcher’s first pitch strike percentage (F-Strike%) is often used to gauge how efficient certain hurlers are. The metric might also have an application for hitters, though. Over small sample sizes, hitters with abnormally high batting averages on balls in play (BABIP) or home run to fly ball ratios (HR/FB%) are considered to be indicative of good or bad luck, and may signal an eventual regression towards the mean. If hitters do better when they get ahead in the count, looking at their F-Strike%’s may also provide insight into how sustainable their level of production is.

In 2014, the Yankees seemed to catch lightning in a bottle by trading for third baseman Chase Headley. Headley had struggled in San Diego, with a .651 OPS in 77 games for the Padres. With the Yankees, he had a .768 OPS, also impressing with his glove. He experienced upticks in both of the “luck” stats with the Yankees, but his F-Strike% plummeted as well. The league average F-Strike% for the 2014 season was 60.6%. After being traded to the Yankees, Headley’s F-Strike% dropped from 58.6% to 51.8%.

Since then, Headley’s F-Strike% has rebounded, while his offensive numbers have regressed. Obviously, several factors have contributed to his diminished production, but the fact that he was seeing a very low percentage of first pitch strikes might have signaled his impending regression.

On a year-to-year basis, certain hitters are predisposed to see more first pitch strikes. Looking at every hitter’s single-season stats since 2012 (with a minimum of 300 plate appearances), metrics like hard-hit percentage (Hard%) and chase rate on pitches outside the strike zone (O-Swing%) have a statistically significant effect on F-Strike%. For any statheads, the equation from the linear regression is as follows:

F-Strike% = 54.621 + 0.322 * (O-Swing%) – 0.148 * (Hard%)
R-squared = 0.286, n = 1340

The data suggests that pitchers are more likely to attack light-hitting batters who are less selective at the plate. In 2016, noted free-swingers Yasmany Tomas, Alcides Escobar, Salvador Perez, Jonathan Schoop, and Brandon Phillips had the top five F-Strike%’s among qualified hitters. The bottom five included Bryce Harper, David Ortiz, Brett Gardner, Carlos Santana, and Mitch Moreland, five of the most selective hitters in baseball.

For hitters who are constantly plagued by poor plate discipline, tweaking their approaches might force opposing pitchers to be more careful on the first pitch of the at bat, which would theoretically have a compounding effect on their production at the plate. One example of a great first pitch hitter is former Yankee Robinson Cano. Despite having an above average O-Swing% every year of his career, Cano has had a below average F-Strike% for the last three seasons.

It makes sense, as he tends to do damage when he does swing at the first pitch. In 2016, he swung at the first pitch 247 times, putting the ball in play on 113 occasions. On those 113 at bats, he had a .416 batting average and a .814 slugging percentage. His average exit velocity for those at bats was 93.5 mph, compared to his 2016 total of 90.8 mph.

It is possible that by forcing pitchers to respect his ability to punish first pitch mistakes, he has forced them to be more careful on the first pitch, which in turn causes them to throw fewer first pitch strikes, ultimately improving his overall numbers.

In the future, teams might consider looking at a hitter’s F-strike% to see whether it impacted his performance over a small sample size. They should also look into teaching their less selective hitters how to guess effectively on the first pitch, especially if opposing pitchers are more likely to leave one over the heart of the plate. Getting more aggressive hitters to suddenly show Joey Votto-like patience has proven to be next to impossible, so changing their first pitch approaches might be the next best thing.

Data is courtesy of FanGraphs and Baseball Savant.