Nick Pivetta Is Turning Back the Clock

I’m young enough to remember when Nick Pivetta was a darling of the analytics community. As a 25-year-old with the Phillies, Pivetta was a big breakout pick after an impressive 2018 campaign. His fastball averaged 94.8 MPH with a high spin rate to boot. He struck out 27% of batters, ranking 13th out of 58 qualified starting pitchers.

Things haven’t gone great since that season, though. Pivetta has yet to really capitalize on the potential he flashed in his 2nd season. He has never posted an ERA below 4.50, and his stuff has slowly deteriorated.

So why am I writing about him? Pivetta is trying new things this spring, and there’s a chance we will see at least some of the potential that had the analytics community excited back in the day.

 

The New Curveball

 

Did you know Nick Pivetta went to Driveline this past Winter? The patented “He went to Driveline” motto has rung through Twitter this spring as fantasy players look for pitchers who made tangible changes to their arsenals. Pivetta flew under the radar a bit, probably because we didn’t see any sexy edgertronic video clips of him from Driveline employees.

According to Pivetta, his goal this offseason was to modify his curveball so it’s “in the zone longer at a better speed.” His 2022 curveball was “more out of the zone, in the zone, out of the zone. This one is in the entire time,” he said. The early results indicate that his off-season work is translating to the field. Pivetta’s curveball has looked vastly different this Spring.

Pivetta’s curveball is doing exactly what he said it would do: it’s being thrown significantly harder, with about six inches less drop. His new curveball velocity of 81.2 MPH would have landed in the 78th percentile last season. Moreover, Pivetta has seemingly made a change to his slider shape, as it now has about six inches more drop in 2023 Spring Training than it did last season, sacrificing only a tick of velocity. Pivetta has moved his two breaking balls closer together in velocity and shape.

 

The Old Curveball

 

Pivetta is moving from a big, downer curveball shape to a tighter, harder curveball. The question remains: is this a good decision?

Last season, Pivetta’s curveball had the most induced vertical drop of any curveball in baseball. The pitch had 6.8 more inches of vertical drop than similar MLB curveballs at his velocity of 77.2 MPH. That ranked ninth among the 236 qualified curveballs last season, according to Statcast.

That’s really good, right? All else equal, yes, more drop is generally better for breaking pitches. So, why did Pivetta’s curveball get absolutely tagged last season?

Pivetta’s curveball was the worst in baseball on a per-pitch basis and in totality, according to run value. The massive drop Pivetta induced on the curveball clearly wasn’t doing anything for the pitch’s success, despite generating a healthy number of ground balls and called strikes. The pitch didn’t miss bats or suppress exit velocity (even if he did get ground balls on it), and he couldn’t command it well.

Pivetta’s comments about the out-in-out properties of the curveball made it sound like he didn’t have a great feel for it, and the results bear that out. Pitcher List has some excellent location/approach metrics to quantify where a pitcher is throwing his pitches. Pivetta’s curveball was located low of the batter (loLoc%) only 47.4% of the time, which ranked in the 11th percentile among starting pitchers. Location+ from Eno Sarris gave it a sub-optimal rating of 92.1. It’s likely that the crazy amount of drop on the pitch made it hard for him to command. Here is how Pivetta located the pitch with two strikes, when swing rates generally skyrocket.

Inconsistent location led Pivetta to leave too many pitches in the zone. Curveballs with that shape and velocity need to be located down in the zone. Opposing hitters lick their chops if that pitch is left up in the zone because it’s a) slow and b) loopy. Boy, did hitters lick their chops a ton off Pivetta’s curveball. This home run from Salvador Perez illustrates the chop-licking pretty well, as he jumped all over this curveball and sent it over the monster. (I’ll stop talking about licking stuff now, sorry)

It’s hard for the pitch to be worse than it was last season; any kind of adjustment Pivetta made to the pitch would be a positive one.

 

Arsenal Interaction

 

I already mentioned how 2018 was the best season of Pivetta’s career. Despite putting up an ERA north of 4, his other ERA estimators indicated a pitcher hurt by a hitter’s ballpark and batted ball luck. His xFIP, FIP, and xERA were all in the mid-3s, and his dominance was built off the back of his curveball. His curveball chase, whiff, and zone whiff rates were at their peak in 2018. Interestingly enough, the slider was also at its best in 2018, putting up career-best whiff and barrel rates. I don’t think that’s a coincidence.

Looking at the spring training numbers, it’s clear that Pivetta is using 2018 as a blueprint. Both breaking balls are within two inches of induced vertical break of their 2018 values at about the same velocity. I think the interaction between his two breaking balls is crucial, and they can’t be looked at in a vacuum. Looking at the pitches by their vertical break (using gravity to account for velocity), we see that the larger the gap has gotten, the worse the results have been.

The two pitches have had extremely distinct shapes for the past three seasons. Since 2018, the slider has been more like a cutter/slider hybrid thrown 7-9 MPH faster than the big looping curveball with 19-22 inches of induced vertical break between them. In 2018, the slider was thrown 4.8 MPH faster than the more slurve-like curveball with only a 14.1 induced vertical break difference. I’m just spitballing here, but I think the more different these pitches became, the easier it became for hitters to identify. This led to fewer chases out of the zone, fewer whiffs, etc.

By merging the movement and velocity gap between his two breaking balls, Pivetta should be able to keep hitters a bit more off-balance. Moreover, by shortening the length of his curveball, he should be able to command it better. Compare the heat map from above showing his 2022 two-strike curveball location with the same image from 2018:

Boy, that’s pretty. With two strikes, a well-located breaking ball is almost guaranteed success, no matter the pitch’s shape.

Given the proximity to his 2018 pitch data, alongside some early Stuff+ numbers, we can get a decent sense of how Pivetta is going to perform this coming season. Stuff+ says the new curveball is 56 points (!) better than his old curveball, moving from a below-average pitch to a plus offering. ATC and Steamer both project a 4.40 FIP for Pivetta in 2023, but I’ll take the under.

Pivetta has all the making of a solid starter in fantasy and reality. He’s a workhorse who has pitched over 155 innings in three of his five full seasons. He still possesses a good fastball that induces whiffs through lots of rising action. He has shown flashes of really good stuff, so we know it’s in there. It may be back already – he has posted a 115.1 stuff+ so far in spring games, and it’s on the back of the curveball improvement. The floor is there with the innings, and in a quality starts league, you can rest assured that Pivetta will provide value.

He’s currently being drafted 404th overall in NFBC leagues, behind Corey Kluber, MacKenzie Gore, Bailey Ober, and Cal Quantrill. I would rather have Pivetta over all of those guys. If Pivetta can replicate a shred of his 2018 self, there’s no reason he shouldn’t be a top-100 pitcher in fantasy this year.