The pitch that helped Zack Britton return to dominance in '19

Zack Britton returned to his old, dominant self in his first full season in pinstripes this year.

After scuffling a bit—at least for his standards—in 2018, Britton pitched his way to a dominant 1.91 ERA across 66 appearances in 2019. His peripherals weren’t as dominant as you’d think (3.47 DRA, 3.74 FIP, 3.59 xFIP, 3.81 SIERA—so still pretty good) because of his career-high 13.1% walk rate (32 walks in 61 1/3 innings pitched).

You can kind of live with Britton’s high walk numbers and peripherals because he’s good at what he does… being an elite ground ball pitcher—so it’s okay if runners reach via walks if he’s just going to erase them with a ground ball. His ground ball rate went up from 73.0% in 2018 to 77.2% in 2019—his highest ground ball rate since his historic 2016 campaign.

He still very much limited base hits like he’s always done, holding opposing hitters to a .179 batting average in 2019. His expected batting average against (.201 xBA) ranked in the 91st percentile in all of baseball, as his expected slugging against (.288 xSLG) ranked in the 98th percentile, while his expected weighted on-base average against (.248 xwOBA) ranked in the 87th percentile.

Britton has been known as strictly a sinker-ball pitcher since his move from the starting rotation to the bullpen in 2014. Britton had thrown his sinker at least 84% of the time in each of the last four seasons and the first half of 2019—it’s really around 90%, but sometimes his sinker got classified as a four-seam or two-seam fastball.

He decided to change things up in July. Sure, Britton had pretty solid numbers through the first half of the season (2.55 ERA, 4.26 FIP, 4.03 xFIP, 4.16 SIERA, 83.3 strand rate in 35 1/3 innings through June 30), but he got even better when he started throwing his slider a whole lot more.

https://sporty-clips.mlb.com/80d04429-f8ef-49d6-820d-ccebdc816fe8.mp4

https://sporty-clips.mlb.com/1c5513d5-5604-44fb-aa35-d6dcbee67407.mp4

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He went from throwing his slider 10% of the time in the first half to 21% of the time in the second half (24.5% in the postseason). He was practically untouchable after doing that, posting a 1.04 ERA (3.02 FIP, 2.98 xFIP, 3.32 SIERA, 93.2% strand rate), while also striking out 26.7% of batters (only 11.9% walk rate), which jumped from his previous strikeout rate of 18.1% during the first half of the season.

Britton’s slider sported a top-5 in baseball (minimum 130 pitches) vertical movement average of 7.8 inches en route to a staggering 56.1% swing-and-miss rate on swings against the breaking ball.

https://sporty-clips.mlb.com/42305d40-76b5-4aee-8703-90e8ba368487.mp4

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The success Britton had using his slider all season was astonishing. His slider—according to FIP and xFIP—was not only the best slider among any pitcher that threw their slider at least 130 times in 2019, but it was the best overall pitch in all of baseball (out of pitches thrown a minimum of 130 times, of course). Britton’s slider had a -1.61 FIP and a -2.34 xFIP during the regular season.

Wow… just wow. His slider was so outstanding that his FIP and xFIP were pretty far into the negatives.

Britton led Yankees’ pitchers in wOBA off sliders this season, including the postseason, with a .042 wOBA against him. He was followed by Aroldis Chapman (.227 wOBA), Masahiro Tanaka (.242 wOBA), Chad Green (.248 wOBA), Adam Ottavino (.257 wOBA), and Luis Cessa (.275 wOBA).

That’s pretty good to see out of your pitchers that were heavily reliant on their sliders (Tanaka, Ottavino, Cessa) or were starting to increase their usage of their sliders (Britton, Chapman, Green).

Anyway, Britton allowed only one hit—a line-drive single left field to Eduardo Escobar on April 30 in Arizona—while throwing it all season. Hitters had an .033 batting average against it (.080 xBA, .051 wOBA, .095 xwOBA, .033 SLG, .092 xSLG) during the regular season.

If you include the postseason, hitters were 1-for-36 (0-for-6 in the ALDS and ALCS), so that’s a .028 batting average, along with 29 strikeouts against the breaking ball. That’s an 80.6% strikeout rate on his slider.

Nobody else comes within the same solar system of that. That’s just absurd. Hilarious, even.

https://twitter.com/MaxWildstein/status/1186448925806514178

Of course, you can’t really say a pitch only thrown 133 times (in the regular season) is the best pitch in baseball. It’s Britton’s secondary pitch. That’s why even when he increased its usage, his slider was only thrown barely over 20% of the time in the second half. 133 pitches is a small sample size.

Seeing these numbers might make you think, “Why doesn’t Britton throw it even more after seeing this gaudy results?”

Well, you’d have to think one big contributor to its success is that he’s primarily a sinker-ball pitcher, so him throwing his slider every now and then straight-up fools hitters. However, to “preserve” himself for the future, Britton might look into throwing it more if the results are anywhere near as good as they were this season.

Everyone saw the effect of becoming a two-pitch pitcher had on Aroldis Chapman in 2019, as he had arguably his best season in pinstripes.

From 2015-2017, Chapman was throwing his four-seam fastball around 80% of the time and his slider just 15% of the time (he’d regularly sprinkle in a changeup 3-5% of the time). However, his four-seam fastball velocity averaged out at 100.2 mph, 101.1 mph, and 100.1 mph in those seasons.

That’s just not where his fastball is anymore... it’s only averaged 98.7 mph in 2018 and 98.1 mph in 2019. Because of that, he had to break open his slider more. He threw his four-seam fastball only 59% of the time in 2019, opposed to his slider, which was thrown 31% of the time (10% of his pitches were classified as sinkers).

Chapman’s slider itself has been elite, just like Britton’s. He posted a -0.36 FIP, -0.85 xFIP, .165 wOBA, and a .104 xwOBA with his slider in 2018 and a 1.86 FIP, 1.29 xFIP, .230 wOBA, and .224 xwOBA with it in 2019.

Like Chapman, Britton’s sinker velocity has dropped over the years. His sinker velocity averaged out at 96.6 mph, 97.0 mph, and 96.1 mph from 2015-2017. In the last two seasons, it’s dropped in average velocity to 94.9 mph in 2018 and 94.8 mph in 2019.

When you start losing velocity and—in Britton’s case—depth on a pitch, you have to start thinking of new ways to help yourself out.

Aroldis Chapman did it. CC Sabathia allowed himself to pitch a few more years in the big leagues before retiring when this year’s season concluded by making changes to his arsenal.

Speaking of Chapman, the All-Star closer reached a new deal with the Yankees late Saturday night that netted him an extra year. Pretty much, he'll be under contract through 2022 on a three-year, $48 million deal with New York. That means all of the key horsemen from the Yankees' 2019 bullpen (Chapman, Britton, Ottavino, Kahnle, Green) will be returning to their pen in 2020.

Anyway, Britton and the Yankees decided it was best to start throwing his slider more and that was a great idea on both of their parts. Clearly.

It will be interesting with Larry Rothschild leaving his post as the Yankees’ pitching coach to see not only who the organization brings in to fill his role, but how the next pitching coach wants to use Britton’s nasty slider.