Boston Red Sox Reliever Brad Ziegler

The Boston Red Sox made splashes this offseason when they acquired both closer Craig Kimbrel and reliever Carson Smith on the trade market. Injuries have shelved both players, resulting in the acquisition of yet another reliever for the back-end of the bullpen as Koji Uehara is also ailing. Ian York uses PITCHf/x to analyze Red Sox reliever Brad Ziegler to see what he brings to Fenway.

The Red Sox traded two prospects (Jose Almonte and Luis Alejandro Basabe) to the Arizona Diamondbacks for veteran reliever Brad Ziegler, shoring up the Boston bullpen as both Junichi Tazawa and Craig Kimbrel are experiencing health issues. Ziegler has been a well above average pitcher since he entered the majors in 2008, with a career ERA+ of 164; so far in 2016, he has a 2.82 ERA (155 ERA+) in 38.1 innings pitched.

Ziegler features three pitches: a two-seam fastball or sinker (“SI”), changeup (“CH”), and curve (“CU”). The pitches are well separated by velocity and movement. (Ignore the one curve that PITCHf/x mis-classified as a changeup.)

Taking his historical usage from Brooks Baseball, and his 2016 game-by-game usage from PITCHf/x, his mix looks like this:

Although Brooks Baseball shows him switching from a four-seam fastball (“FF”) to a sinker around 2011, this is mainly just a change in nomenclature, because the “four-seam” and “sinker” have essentially identical speed, and horizontal and vertical break. Ziegler’s main change over time has been that he has gradually increased his changeup usage.

Brooks Baseball also calls his breaking pitch a slider, but this pitch is in the usual speed range for a curve and is slower than the vast majority of sliders, so I call it a curve here. In the 3D pitch clustering chart above, there are two pitches that PITCHf/x identifies as two-seam fastballs, but that have similar vertical movement to the curve; if these are not PITCHf/x errors, they may be Ziegler’s test of a true slider.

As the pitch characteristics chart shows, Ziegler is hardly a flamethrower. His pitches this year haven’t topped 87 mph, and his sinkers average just 83.9 mph. His speed has dropped each year since 2012, but even then his average fastball/sinker velocity was unimpressive at about 87 mph.

However, it’s misleading to focus on Ziegler’s velocity, because as a submarine-style pitcher, none of his pitches are normal. With the spin essentially reversed, they move in the opposite direction to their conventional counterparts. For example, we can compare the movement of Ziegler’s “sinker” to that of another right-handed sinkerball pitcher, Rick Porcello:

In these charts, the solid lines show the path that the pitch would take under the influence of gravity alone — that is, if there was no air for the ball’s spin to work on. The dots show the location of the ball every 1/100 of a second. The extent to which the dots diverge from the solid line shows how much movement the pitch has due to its spin.

Porcello’s sinker is a conventional, high-quality two-seam fastball. Like a normal fastball, it has backspin that makes the ball rise compared to its gravity-only path. Because Porcello wants the sinker to contrast with his four-seam fastball, he adjusts the spin to make more side spin (causing the extreme horizontal movement that’s seen in the top view), and reduces the backspin. Since he can’t eliminate all backspin, the ball does rise a little (as seen in the side and front views).

Ziegler puts the same spin on the ball relative to his pitching motion, but because he throws underhand, the actual spin is reversed. This pitch has true frontspin as well as sidespin, and instead of rising relative to the gravity-only path, this pitch actually drops several inches, as well as having significant horizontal movement. His changeup does the same thing, only slower. These pitches move more like a left-handed pitcher’s slider or curve than a conventional righty’s fastball.

As you would expect, the opposite is true for Ziegler’s curve. In his case, throwing with a curveball spin puts backspin as well as sidespin on the ball, and the curve has significant rise compared to the path it would follow with no spin, whereas Porcello’s conventional curve drops:

Even though Ziegler isn’t going to overpower anyone with his velocity, the non-standard movement on his pitches due to his delivery has made him very effective at fooling batters. While he doesn’t strike out many (his K/9 of 6.34 puts him at 253 out of 296 pitchers with at least 30 innings pitched this year), he draws a huge number of ground balls: he is fifth in ground ball rate in 2016. He should be a strong addition to Boston’s bullpen, and, if necessary, could fill in as closer while Kimbrel is on the DL.


Ian York uses the PITCHf/x to monitor the strike zone, highlights great performances, monitors league-wide trends and tracks the performances of some interesting young hitters.

Follow Ian on Twitter @iayork.

All data compiled from PITCHf/x and Baseball-Reference.com.

About Ian York 208 Articles
Ian is an immunologist and virologist who lives in Atlanta with his wife and two sons. Most of his time is spent driving his kids to baseball and soccer games, during which he indoctrinates his children on the glories of Pedro Martinez, the many virtues of the Montreal Expos, and other important information.

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