On the Relationship of Pitch Tempo and Defense

One of the most prominent stories of the early part of the 2023 season is the implementation of the pitch clock. The most aggressive part yet of MLB’s sustained battle to reduce game times and increase the pace of action on the field, the pitch clock rule dictates there be no more than 30 seconds between batters, 15 seconds between pitches within an at-bat with the bases empty, and 20 seconds between pitches with runners on.

Pitchers must begin their motions before the clock expires, or risk being charged with an automatic ball and batters must be in the box and ready by the 8-second mark or chance being charged with an automatic strike.

This topic has dominated the first few days of Spring Training games. There will undoubtedly be some awkward growing pains as habits are adjusted and everyone resets their internal clocks. While that happens there will be called automatic strikes or balls at inopportune moments (like has already happened in a Grapefruit League game between Atlanta and Boston). Players and teams will figure out ways to exploit the unexpected loopholes in the new rules.

But everyone will adjust with a little time and patience, as many minor leaguers have attested about their experiences the past few seasons. The spirit of the clock rule isn’t about rushing the game and arbitrarily affecting outcomes. It’s about eliminating stuff like this:

And it’s about eliminating pitchers walking around the mound for a few seconds between every pitch. And eliminating batters stepping out to re-do their gloves when they haven’t even swung at a pitch. It’s all about culling out dead time with no game-related action and making stuff like this a thing of the past:

The results from the minor league pilots with a pitch clock are undeniable. The average time of nine-inning games shrunk by nearly 20 minutes in the highest levels of the minors the past few seasons. The early returns of the first few days of Spring Training games suggest it’s reducing Major League game times by at least that much. It likely won’t be quite that significant of a reduction at the major league level once games start to count – and it’s worth watching if the league claws back some of that time via longer advertising breaks over time – but the overall impact should be overwhelmingly positive.

As happens with any gameplay change, this will also give broadcasters and color commentators something to opine about. You will undoubtedly hear those mostly former ballplayers offer an axiom along the lines that an increased pace of play will be a benefit to the pitchers because their teammates will be more engaged on defense. It’s long been held up as true that pitchers who work quickly reap the rewards of higher-quality defense played behind them because it helps defenders “stay on their toes”.

Is that really true? In light of the new rule, I thought that might be an interesting question to explore today.

Tempo and Outs Above Average

Let’s begin the investigation by looking for a relationship between two of the newer Statcast measurements: pitch tempo and the defensive stat Outs Above Average (OAA). Statcast has been calculating OAA since 2016 and Pitch Tempo for even longer, so we have a data set that includes the past six seasons where we have both measurements.

Pitch tempo measures the median time between pitches within a plate appearance and breaks those down by bases empty and runners on base situations at both the individual and team levels. I calculated a weighted average of the bases empty and runners on situations to get one tempo mark at the team level for each team season since 2016 (210 seasons in all) and compared that with each team’s OAA marks from those seasons.

If the old adage that pace leads to better defense were true, we’d probably expect to see a relationship indicating that teams with the fastest pitch tempos would also be among the best by OAA. But that’s not evident from this data. I ran a correlation analysis on the two data sets and got a statistically significant R-squared value of -0.049. The closer a correlation value is to 1 or -1, the stronger the relationship between the two variables. That value suggests the relationship between pitch tempo and outs above average is almost negligible. Below is a scatter plot of that data. You can see there is no discernible pattern:

Data from Baseball Savant

This finding tracks with previous work by Mike Fast in 2008 that explored pitcher pace with defensive efficiency and batting average allowed on balls in play. Fast, who would later work for the Houston Astros and Atlanta Braves, found then that the relationship between pace and defensive efficiency and defensive performance on balls in play, if it existed, was not strong.

I completed the same exercise with the other major defensive metrics – ultimate zone rate, defensive runs saved, defensive runs above average, and Statcast’s success rate – and found similar results. You can see the correlation values in the table below. It’s clear that, if there is a relationship, it’s very weak.

Data from Baseball Savant and FanGraphs

Tempo and Free Bases Allowed

Maybe pace does not lead to better defense by the advanced metrics, but perhaps it leads to fewer defensive mistakes. I’ve written before about the Twins and free bases allowed – the summation of a team’s walks, hit-by-pitches, balks, stolen bases, errors, wild pitches, and passed balls allowed. It seems logical that pitchers and defenses that are fully engaged by the pace of play will yield fewer of these self-inflicted mistakes that only benefit the opponent. Right?

From that previous work, I have a data set of each team’s seasonal per-game averages of free bases allowed since 2016, and I used it to do the same exercise as the previous section. The correlation result was -0.002 and the scatter plot again showed little in the way of a clear relationship:

Data from Baseball Savant and FanGraphs

So, given these results, it seems that the old adage about pitchers working quickly resulting in better defense being played is mostly a myth.

That’s not to say that pace does not matter, though. A clear relationship may not exist in the aggregate, but Fast found that there might be some effect in the extremes, noting that pitches thrown within 10 seconds after the previous pitch had a significantly lower BABIP (.281) than pitches thrown more than 50 seconds after the previous pitch (.366) and at-bats that took 15 seconds or less had a BABIP of .314, whereas at-bats taking longer than two minutes had a BABIP of .334.

In any event, I am wholeheartedly in favor of the pitch clock and the push to get a better pace on the field. But it seems we’d all be well served to take the expert commentary we’re going to hear about the effects of better pace on the defense with a grain of salt.

---

John is a writer for Twinkie Town and Pitcher List with an emphasis on analysis. He is a lifelong Twins fan and former college pitcher. You can follow him on Twitter @JohnFoley_21.