Nick Pivetta’s High-Wire Act

After trading Mookie Betts and David Price the prior offseason, the Red Sox figured there was still enough depth in the starting rotation to get through 2020 and contend. However, Chris Sale, Eduardo Rodríguez, and Nathan Eovaldi all missed time due to injury, and Boston was left with no starting rotation just weeks into the start of last season. Chief Baseball Officer Chaim Bloom and GM Brian O’Halloran, as many of us already knew, realized that the pitching had to be overhauled.

This is where the Red Sox brass figuratively started throwing things against the wall. While a lot would fail, there was a chance some of them would stick. Martín Pérez, Austin Brice, and Phillips Valdéz are some of the few that stuck, but they weren’t difference-makers and Boston found themselves as one of the worst teams in baseball at last year’s trading deadline. There, an opportunity presented itself. The Phillies, desperate for bullpen help, traded for Brandon Workman and Heath Hembree in exchange for pitching prospect Connor Seabold and the talented Nick Pivetta. Pivetta flashed his plus potential in the three previous seasons, but consistent underperformance made it easy for the Phillies to cut bait.

For the Red Sox, this was an extension of a plan. They not only took a chance on the talent but felt they could make changes that would make the right-hander better. After spending a few weeks at the alternate site, Pivetta finished out the 2020 regular season with two starts, going 2-0 in two starts with a 1.80 ERA across 10 innings. It was another success in Boston’s long-term goal of making a complete pitching staff.

To start 2021, Pivetta has further cemented his place in the rotation, pitching to the tune of a 3.38 ERA while going 4-0 in six starts. But if you look under the hood, you’ll see an obscene 15.1% walk rate, a low .278 BABIP, and a microscopic 3.8% HR/FB. Tally them all up, and you get a pitcher that is screaming regression. That is if this wasn’t all by design.

 

Walking A Fine Line

 

One stat that is particularly useful in this exercise is two-strike%. It’s a simple measurement, just taking the percentage of total pitches that are thrown in two-strike counts. By using it, you are looking at pitchers who are throwing in the most advantageous situations for success. Nick Pivetta falls just short of the top-ten (at least 400 pitches thrown this season), 12th best at 34.1%. For someone that has walked 15.1% of batters to date, it doesn’t make a ton of sense that the right-hander finds himself on such a list. Now, if you check the percentage of pitches thrown in three-ball counts, you’ll find Pivetta 30th at 9.2%. It’s befuddling to see a pitcher leading in two diametrically opposite stats, but there could be a connection to Pivetta’s approach.

For anyone that has watched Pivetta in his young career, home runs have always been a problem. The average home run to fly ball ratio (HR/FB) falls between nine and ten percent. Pivetta is far from the norm, as the right-hander has consistently posted rates well into the teens, the lowest being 15.8% in 2018. His current 3.8% mark is not only a fraction of what it normally is for Pivetta, but it’s significantly lower than the average.

Now, you’re probably asking yourself, “How can a pitcher change his outlook so drastically?” That starts with how he uses each pitch.

The 28-year-old has traditionally given up most of his home runs on the heater, with 44 of his 74 home runs allowed coming off the pitch. So far in 2021, Pivetta has increased the four-seamer usage rate to 54.2%, the highest of his career; yet the only long ball Pivetta has allowed was off a hung slider to Maikel Franco at Camden Yards.

The seismic shift in Pivetta’s four-seamer has come from where he’s placing it, putting aside his formerly brash approach in exchange for little more dexterity.

Amongst pitchers that have thrown at least 150 four-seamers this season, Pivetta has placed the 11th most heaters in the top shadow zone. Since he’s altered his release point since reaching Boston, throwing the ball closer to his body and slightly higher, the right-hander now has 11.1” of drop on his fastball — the lowest of his career — which makes it difficult for hitters to square up at the top of the zone. Of course, if you can’t square it up, you are certainly not hitting it for a home run.

The emphasis on ‘finesse’ hasn’t just been on his fastball, however, as his slider and curveball both been used similarly.

The slider is the pitch that Pivetta has exhibited the greatest amount of control with. While the right-hander is sporadic more often than he should be with the fastball, he shows no such recklessness on the slider. Elevating the percentage of sliders in the shadow zone to 44.9%, a figure that is 13th most this season, is just another example of the feel he’s gained for the pitch. One thing this approach hasn’t brought is swings outside the zone (25.3% O-Swing) and whiffs (15.6% SwStr), as the league averages are 31.6% O-Swing and 17% SwStr. However, it has allowed him to generate weak contact.

The knuckle curve exhibits similar traits to both the four-seamer and slider. Like the heater, Pivetta’s bender has also likely changed in movement because of the altered release point, where there is now 5.7” more vertical drop (+7.2” against average) and 2.8” less horizontal break (-0.6 against average) than a year ago. And, similarly to the slider, Pivetta has thrown the curveball in the fringes of the zone, as evidenced by the 58.3% of pitches in the shadow and chase regions. Combined, you have a pitch that gets few swings outside of the zone (15.1% O-Swing) and even fewer whiffs (7.1% SwStr) than the league average curve (25.6% O-Swing, 13% SwStr). Though the curve has far exceeded expectations so far relative to its xwOBAcon, it is still discouraging to see such a large expected contact figure, to say the least.

Since all three of his pitches all have sub-50% Zone rates (49.5% for FF, 47.9% for SL, and 36.9% KC) and aren’t getting hitters to chase or whiff at an above league average rate, it’s no surprise Pivetta’s walks have spiked.

 

Living Dangerously

 

Pivetta’s focus on accuracy is unlike any approach we have seen from the right-hander in prior seasons, but it’s yielded some unexpected results. While the 3.38 ERA and 3.33 FIP speak to his early success, his 4.75 SIERA, 4.13 xERA, and 4.42 xFIP suggest a steep fall over the long run, if nothing changes. Given that there seems to be a method behind the madness in Pivetta’s prevention of home runs by his approach, he should be able to likely outperform his xFIP through the year. But considering he doesn’t have any wipeout offerings at the moment, Pivetta is heavily relying on generating weak contact as his means of production, which is far beneath his potential. Figuring out how to optimize his batted-ball suppression and strikeout ability needs to start with how he uses his refined 12-6 curveball, as it’s an important third pitch that needs to add some more swinging strikes if Pivetta is to not only keep an upper-20% strikeout rate but to also keep his currently pristine 3.38 ERA.