Revamping Nick Pivetta Into an Ace

Nick Pivetta disappointed in 2019. Is he ready to turn a corner?

Every year, fantasy baseball writers release articles detailing their “sleeper” picks who might be undervalued or are on the verge of a breakout. With this yearly cycle of people listing their favorite sleeper picks occasionally you will have a player who is listed on so many sleeper lists that they transcend their sleeper tag and become regularly known players. Entering the 2019 season, Nick Pivetta was arguably the most well-known sleeper player in the draft. He was coming off a 2018 sophomore season in which he posted 164 innings pitched, a 3.51 SIERA, and almost 3 fWAR. There was a legitimate reason to be excited for Pivetta’s future, but his 2019 season was nothing short of an absolute disaster.

Pivetta went from striking out 27% of batters in 2018 to 21% in 2019. This was accompanied by his walk rate rising by 2%, so it is easy to tell he was not sacrificing his stuff to improve his control. He was sent to the minor leagues after struggling early in the season, and despite success at the AAA level (3.07 ERA in 41 IP), he was transitioned to a bullpen role when he returned to the MLB level towards the middle of the season. Once he transitioned to this bullpen role, his K% saw a dramatic rise back to his 2018 levels from 19% to 27%, but he still struggled with his control which is likely why he did not see much success in the back half of the year.

Over the course of those first couple months of 2019, Pivetta went from being a potential frontline starter to being organizational depth or a bullpen option. For a starting pitcher whose 2019 closest comparisons according to Baseball Savant were Justin Verlander, Trevor Bauer, and Mitch Keller, it is quite surprising that Pivetta would not have had a longer leash than a traditional young starter.

This begs the question as to whether there were deeper indications that Pivetta’s future was bleaker than many had believed. Digging into the difference between his 2018 and 2019 seasons, one of the most notable changes was his increase in the usage of his curveball. His percentage increase in curveball usage from 2018 to 2019 was the second largest in baseball among pitchers who threw at least 1500 pitches (Only behind Tyler Mahle who increased his curveball usage by 23%!). Pivetta’s curveball is nasty, and he gets above-average horizontal and vertical movement on it. His curveball spin ranks in the 92nd percentile in spin and is listed among names like Gerrit Cole and Charlie Morton, both of whom are known for utilizing exceptional curveballs. An interesting note is that Aaron Nola and Nick Pivetta both threw their curveballs 35.2% of the time which could have been an organizational trend through the addition of J.T. Realmuto or former manager Gabe Kapler’s pitch calling.


Curveball Usage – xwOBA

Looking at the batted ball data above it is clear to see that Pivetta’s increase in curveball usage was not the problem, and perhaps he could benefit from another increase in usage of his elite curveball. He only uses his slider 12.2% of the time, and he posted a .317 xwOBA with the pitch, so that leaves us with Pivetta’s fastball. He has a sinker and a changeup, but he only threw both of those pitches less than 10% of the time in 2018 and 2019.

Pivetta has a four-seam fastball that he throws roughly 50% of the time (49.3%). His usage of his fastball has dropped by four percent since his rookie campaign in 2017. His fastball’s spin ranks in the 65th percentile and his average fastball velocity was 94.6 (75th percentile). This pitch also ranks as the 38th and 39th highest horizontal and vertical movement among pitchers who threw at least 500 fastballs in 2019. It has all the makings of a potential plus pitch, but it got absolutely crushed by hitters in 2019.


Fastball xBA – xwOBA

In comparison to the MLB average, this is the pitch that absolutely killed Pivetta in 2019, but we have already established that his fastball should not be nearly this bad. Below is a flow chart of Pivetta’s usage of each of his pitches throughout the count of each plate appearance. The conventional wisdom throughout baseball has been that when you fall behind in the count you should stay away from off-speed pitches. The flow chart establishes that Pivetta subscribes to this philosophy and leans on his fastball when he falls behind in the count. This could explain why his fastball’s xwOBA is higher than his other pitches as hitters gain the advantage as they fall behind in the count.

The problem I have with this philosophy is that when you fall behind in the count you are already in a disadvantageous position. This train of thought suggests that the pitch Pivetta is most comfortable throwing in the zone to get a strike is his fastball. However, the numbers disagree and show that he throws his slider in the zone more often than he does his fastball! Not too far behind is his incredible curveball which makes sense that it falls out of the zone as it is mostly used in counts where he is trying to stay out of the zone. There is a legitimate argument that as Pivetta falls behind in the count, he should use his better pitches to attempt to get back into the count.

Pitch Selection Usage – In Zone%



Sabermetricians often criticize MLB teams for not using their best pitchers in the highest leverage situation. The theory behind it makes sense, why save your best pitcher for the ninth inning when you might lose the game in the sixth? The same ideology should be used regarding pitch counts as well. If we think of every plate appearance as an individual game between the batter and the pitcher, when the pitcher is put into a losing position, they should be throwing their best pitches more often than they are throwing their worst pitches. The idea that pitchers typically throw fastballs in the zone when they are behind in the count is well known, and it could end up being advantageous to Pivetta if he started throwing more off-speed pitches when behind in the count.

Nick Pivetta has the potential to be a solid starting pitcher for the Phillies, but if he wants to stick in the rotation and make it work there needs to be some serious work done on his approach. One change he could make is working on developing a fourth pitch, particularly his changeup as that falls right in-between his four-seamer and his slider in terms of velocity. Keep an eye on Pivetta in 2020 if he gets a chance to start. The Phillies are in desperate need of rotation help if they wish to compete in the deep NL East, and perhaps there could be a dark horse sitting in their clubhouse ready to be unleashed.

Photo by Kyle Ross/Icon Sportswire

Joseph Garino

Joseph graduated from Marquette University in 2021 with a degree in Analytics and Economics. He's been an Angels fan since the days of Vlad Sr. and is looking to present complex analytical concepts in a digestible manner.

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