The Rise of the Fastball

The following article was a reader submission by Jason Gindele. You can find his previous articles here and here.

The late Tom Seaver once said: “The good rising fastball is the best pitch in baseball.” 

He may have been on to something. Decades later, some analytics are now pointing to vertical movement as the most important element of an effective fastball — even more than velocity. 

The Pirates have some catching up to do, in this regard. Before we look at the numbers, let’s start with some background.

You’ll often read scouting reports that say a pitcher has a rising fastball, or it carries well, or it has some jump, or it plays well up in the zone, or it rides, or it has a good Z-break. Those are all scouting buzzwords for a four-seam fastball with plus vertical movement. (Two-seam fastballs typically have more horizontal movement.)

The efficacy of a rising fastball wasn’t quantified until recently, and more and more analysts — like Eric Longenhagen in this article over at FanGraphs, or Kevin Goldstein in this one — are coming around to the concept. One of the most interesting data sets was published in September by Ethan Moore, who focused on a new metric called Quality of Pitch (which he now calls Expected Run Value or xRV). Using Statcast data, Moore — who was hired by the Twins shortly after publishing his findings — looked at nine fastball pitch variables and calculated the importance of each on expected outcome:

Vertical movement 9.59
Velocity 8.54
Vertical release position 8.44
Horizontal movement 8.41
Horizontal release position  8.22
Spin rate 5.47
Horizontal position of ball at home plate 4.82
Vertical position of ball at home plate 4.05
Release position extension 3.06

Rising to the top (pun intended) is vertical fastball movement, which is defined by how much or how little a fastball drops due to gravity and spin on the way to the batter. While any meaningful deviation from the norm can be effective, generally, the less it drops, the better. 

Baseball Savant has a handy dashboard of pitch movement that you can filter by fastball vertical movement, and the top pitchers on the 2020 leaderboard are objectively top pitchers in the game, led by Trevor Bauer, James Karinchak and almost-a-Pirate Walker Buehler. And if you’ve seen those guys pitch, you know that their fastballs are key parts of their repertoires:


Obviously, those guys and others aren’t good only because of the ride of their fastballs. They have an array of high-quality pitch attributes, good tunneling, good command, good pitch sequencing, good defenses, good ballparks, etc. But more and more, data is pointing to the rising fastball as an anchor pitch of many top hurlers. 

So how do Pirates pitchers fare? 

Let’s look at the 2020 data over at Baseball Savant, which calculates average movement compared to pitches with a similar velocity and release point. To give you a sense of range, at the top of the leaderboard of qualifying pitchers is Bauer, whose fastball sits 3.9 inches higher than similar fastballs, and at the bottom is Craig Stammen, at 9.2 inches below similar fastballs. (The average is 0.)

With that in mind, here is last year’s four-seam fastball data for the 2021 Pirates:

Nick Mears 2.7
Tyler Anderson 2.1
Michael Feliz 1.5
Sam Howard 1.5
Kyle Keller 1.4
Michael Yajure 1.1
Will Crowe 0.5
Mitch Keller 0.2
Chad Kuhl -0.3
Richard Rodríguez -0.5
Chris Stratton -0.5
Austin Davis -0.7
Cody Ponce -0.7
Steven Brault -0.9
Duane Underwood -1.5
JT Brubaker -1.6
Kyle Crick -1.6
Trevor Cahill -4.5
Geoff Hartlieb -9.0

Here’s the data on Pirates from 2020, 2019, 2018 and 2017, if you are interested. 

Just a gentle reminder that this is fairly new research and there are lots of factors that go into a successful pitcher, which is why Anderson’s fastball had a .369 expected weighted on-base percentage (xwOBA) with the Giants in 2020, despite above average vertical movement. That could be due to his mediocre velocity, horizontal movement, spin rate, extension or other factors. 

As the vertical movement leaderboard showed, though, many of the best pitchers in baseball have a rising fastball, and that’s not a coincidence. Compare Anderson’s fastball xwOBA to that to Bauer (.228), Karinchak (.236) and Buehler (.168). And compare those to Keller, whose straight fastball had an xwOBA of .421 last year. 

Or look at Gerrit Cole. In 2017, his last year with the Pirates, his fastball registered an average vertical movement of -0.3, with an xwOBA of .348. After being dealt to the Astros, who helped Cole make a number of adjustments, his numbers improved to 2.0 and .273 in 2018 and 2.9 and .254 in 2019, when he finished second in AL Cy Young Award voting. 

Adjusting the shape of a pitch isn’t for everyone. Here’s a primer from Driveline Baseball, which will show you why not every pitcher can master a four-seam fastball — such as, potentially, Trevor Williams, who throws from a three-quarters arm slot that makes it a challenge to get the perfect backspin. It’s still early, but the Cubs may be moving Williams away from his four-seam fastball, which registered a -2.7 vertical movement mark in 2020 (xwOBA of .375) and is at -2.9 this year. In 2020, he threw his four-seamer 42.6% of the time. In his first start with the Cubs, he threw it only 29% of the time, with an xwOBA of .240 (perhaps, in part, because hitters saw it less). 

There is room for improvement on the current roster, and it’s an open question as to how the current Pirates front office leaders and analysts are viewing and using this data. Maybe they saw that Anderson and Yajure had some fastball life and decided to pursue them during the offseason. Maybe the player development team will focus on spin direction, tilt and rate to develop better four-seam fastballs in the majors and minors.

With a new administration now settled in and more pitch data available, the key will be seeing how fastball vertical movement and other variables change in the coming years.

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