Statcast Breakdown: Why Pitch Sequencing Matters

After 150 years of baseball, a simple question still remains: what pitch should come next?

It’s a really difficult question to answer. Simply put, a pitch is not defined by a singular characteristic. What good is a 102 mph fastball if it consistently hits the backstop? 102 mph can be a telling datapoint in a vacuum, but it clearly doesn’t tell the entire story.

Take a moment to think about Mets’ wunderkind Nolan McLean. His debut season was a resounding success. He posted a 2.06 ERA, a 2.97 FIP, and demonstrated mastery of his entire arsenal. Each offering of his six-part repertoire filled its respective role admirably—a seemingly-random sequence of pitches bewildered big league opponents every five days, resulting in 30%+ whiff rates against four different offerings. 

Pitch Grading systems, like Fangraphs’s Stuff+ and BPro’s PitchPro, recently introduced to the public realm advanced algorithms designed to discern an entire repertoire’s value, which are applicable in cases like McLean’s, where his fastball isn’t the belle of the ball.

Arsenals perform well when they contain pitches that “tunnel,” sequential pitches that pass through the same path on their way to the plate for as long as possible.  These sequential pairs of pitches work well when they diverge after a batter’s “decision point”—the point in ball flight when a hitter makes a decision when/where to swing. When pitch sequencing is done right, it’s hard for a batter to stay on top of a pitcher.

Conventional baseball wisdom supports these systems’ conclusions. Now, there’s data to back up if the conventional wisdom is working. If a fastball is thrown in the first pitch of an at-bat, the line of thinking typically says a curveball should follow. The former is thrown to disrupt an opponent’s swing on the latter due to the distinct difference in velocity, shape, and movement between the two offerings. Don’t just take my word for it, see this effect in action here.

This GIF visualizes the importance of “paired pitches,” or pitches frequently thrown in tandem. It’s baseball’s answer to a magic trick. You expect the fastball down the pipe, you get a curveball brushing the dish. It’s the phenomenon that demystifies Tyler Glasnow’s success. His fastball screams to the plate while his curveball drops down like an angel falling from heaven.

The aforementioned McLean alluded to this effect in a recent interview with PitchingNinja’s Rob Friedman, explicitly mentioning that he’s looking to pair more cutters with sweepers and fastballs with sinkers in 2026 to change eye level and induce additional whiffs.

How Are the Mets Pairing Pitches?

Thanks to Baseball Savant, we’re able to identify the most frequent paired pitches from the 2025 season and create a public-facing website for further analysis. (Link can be found here.) Given the namesake of this site, let’s start with analysis from the 2025 Mets.

Note that several prominent Mets pitchers from the 2025 campaign weren’t on the 25-man roster during the entirety of the season, which may skew results.

In 2025, Clay Holmes threw a sinker followed by another sinker 365 times.

And for good reason. Holmes’ usage epitomizes one of baseball’s latest trends: throw your best pitch more. Don’t just hear me preach; listen to World Series champion David Price:

“Pitch to your strengths. Make him beat you with your best pitch, with your best stuff.”

Largely on the backings of his sinker, Holmes emerged as the Yankees’ closer early in his career, parlaying his late-game success into a three-year, $38 million contract with the Mets last winter. Just like seasons past, Holmes’s sinker served as his bread-and-butter in 2025, inducing a +10 Run Value, sixth among MLB starters.

In 2023, Yankees columnist Bob Klapisch compared his offering to a bowling ball, noting his sinker dulls results just like a bowling ball would. Fangraphs’ Stuff+ Metric grades it as a positive, an indictment on the pitch’s unique movement profile—15 inches horizontal, 2.9 IVB.

However, using the “Pitch Type” tab—as seen on the center of the website—only tells one chapter in the tale of pitch design. There’s more to the story. As Benoit Blanc of Knives Out fame once put it, there’s a donut hole within a donut hole.

Pitch Pair Types are informative in a vacuum, but their pitfalls relate to their dependence on usage, which can provide more noise than true analysis.

Instead, picture this:

You’re a hitter facing Mets’ starting pitcher Kodai Senga. You know Senga’s fastball plays well in the upper-to-mid half of the strike zone, given the pitch’s historical location tendencies. You also know Senga has a dastardly forkball in his back pocket, a wicked pitch designed to induce whiffs, limit contact, and overall, ruin your 2-for-2 day at the plate so far.

Where would this forkball be likely to be located? On the top half of the plate, or towards the bottom?

The answer, as you may have surmised, is the bottom.

This hypothetical example exemplified Senga’s real-life pitching strategy. Despite an injury-marred campaign, his high fastball/low forkball combination finished among the Mets’ leaders in pitch pairs.

Paired pitches work best when they follow the same path, diverge after the “decision point,” and wind up in two distinct zones of the plate. Senga’s fastball/forkball combination is a prime example.

Senga was far from the only Met to utilize pitch pairs to great success in 2025. Former Met closer Edwin Diaz employed several tactical pairings en route to his dominant campaign.

Few hitters seemed comfortable as Diaz continued to rack up whiffs, often generated by sequential pitches in similar locations. Throughout the season, sequential sliders low-and-away and fastballs up-and-in were thrown 61 times, 7.5% of the time.

Diaz’s calling card was prevalent throughout Major League Baseball.

A series of pitchers’ top combinations were the same offering in the same zone, a somewhat surprising conclusion to even the most diehard of fans. While shocking, this result makes sense. Pitchers often use “waste pitches” to induce a swing-and-miss ahead in the count.

Alternatively, I hypothesize that offspeed pitches wind up in the same zone sequentially, so pitchers can take another nibble at the swing-and-miss.

Diaz threw his fastball up-and-away, followed by a slider down-and-low 16 times in 2025, his third most frequent sequence of the year. This frequent sequence hints that a pitch tunneling effect is in play, giving the impression that the pitches are the same before they diverge to the opposite sides of the plate after their decision point.

A series of conclusions can be generated from just a quick search.

Further insights:

• New Met Devin Williams frequently threw his changeup one-after-another during his sole season with the Yankees in 2025, dancing it around the lower boundary of the strike zone. Given the Mets’ new pitching coach Justin Willard’s emphasis on throwing pitches in the zone, I’m curious if this trend persists in 2026. [Picture]
• 10% of Matt Brash‘s sequences consisted of sliders low-and-away, which led the Majors in 2025 [Picture]
• Unsurprisingly, Tommy Kanhle—famous for frequent change-up usage—followed a change-up with its twin 71% of the time. [Picture]

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Website Usage Guide:

• To select a player, type their name in the drop-down under “Players” on the left sidebar. The default setting is “Clay Holmes.”
• To select a team, type their abbreviated name in the drop-down under “Team” on the left sidebar. The site defaults to show “All Teams.”
• To see sequencing splits, select “L” or “R” in the drop-down under “Platoon” on the left sidebar. The default is “All.”

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Pitch Pairs are nothing new. Managers have called a series of pitch combinations since Fred Goldsmith first twirled his curveball around a pole in a thrilling exhibition of athletic ability back in 1867. In 2017, a trio of Baseball Prospectus writers introduced the concept of “pitch tunelling” to the public realm for the first time with their Introducing Pitch Tunnels article.

The full website can be found here. Forks to the website are welcome. If you’re technically inclined, check out the GitHub repository PyBaseball, my North Star on this journey.

What’s next? Who’s to say? I see this article as a foreword with iterations to follow. There’s a multitude of other variables that impact frequent pitch sequences—movement, velocity, seam orientation, seam axis, batter tendencies—and I look forward to establishing a relationship between their importance and the likelihood of a sequence.

If you (yes, you, the reader) spot something noteworthy on the website, please share. My contact information is available on the site.

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