Pitcher zStats Through the End of May

Sonny Gray
Jesse Johnson-USA TODAY Sports

One of the strange things about projecting baseball players is that even results themselves are small sample sizes. Full seasons result in specific numbers that have minimal predictive value, such as BABIP for pitchers. The predictive value isn’t literally zero — individual seasons form much of the basis of projections, whether math-y ones in something like ZiPS or simply personal opinions on how good a player is — but we have to develop tools that improve our ability to explain some of these stats. It’s not enough to know that the number of homers allowed by a pitcher is volatile; we need to know how and why pitchers allow homers beyond a general sense of pitching poorly or being Jordan Lyles.

Data like that what StatCast provides gives us the ability to get what is more elemental, such as exit velocities and launch angles and the like — things that are in themselves more predictive than their end products (the number of homers). StatCast has its own implementation of this kind of exercise in the various “x” stats. ZiPS uses slightly different models with a similar purpose, which I’ve dubbed zStats. (I’m going to make you guess what the z stands for!) The differences in the models can be significant. For example: when talking about grounders, balls hit directly toward the second base bag became singles 48.7% of the time from 2012 to ’19, with 51.0% outs and 0.2% doubles. But grounders hit 16 degrees to the “left” of the bag, over the same time period, only became hits 10.6% of the time and toward the second base side, 9.8%. ZiPS uses data like sprint speed when calculating hitter BABIP, because how fast a player is has an effect on BABIP and extra-base hits.

ZiPS doesn’t discard actual stats; the actual models all improve from knowing the actual numbers in addition to the zStats. For data on how zStats relate to actual stats, I’ve talked more about this here and here.

But you’re here to see the numbers themselves, not the exposition, so let’s star wipe to the main storyline.

ZiPS HR Overachievers (6/1)
Name HR% HR zHR% zHR zHR% Diff zHR Diff
Sonny Gray 0.0% 0 2.2% 5.4 -2.2% -5.4
Zac Gallen 0.7% 2 2.4% 7.0 -1.7% -5.0
Bailey Ober 1.9% 3 4.5% 7.0 -2.5% -4.0
Dane Dunning 0.0% 0 2.0% 3.9 -2.0% -3.9
Justin Steele 0.7% 2 2.1% 5.8 -1.4% -3.8
Michael Wacha 2.2% 5 3.8% 8.7 -1.6% -3.7
Mitch Keller 2.3% 7 3.5% 10.6 -1.2% -3.6
Bryce Elder 1.5% 4 2.8% 7.5 -1.3% -3.5
Dustin May 0.5% 1 2.2% 4.1 -1.7% -3.1
Nathan Eovaldi 1.1% 3 2.1% 6.1 -1.1% -3.1
Shane McClanahan 2.5% 7 3.5% 10.0 -1.1% -3.0
Adam Wainwright 2.4% 3 4.7% 5.9 -2.3% -2.9
Bryce Miller 1.5% 2 3.6% 4.9 -2.1% -2.9
Logan Allen 1.7% 3 3.4% 5.8 -1.6% -2.8
Andrew Wantz 1.2% 1 4.3% 3.6 -3.1% -2.6
Merrill Kelly 켈리 2.0% 5 3.0% 7.6 -1.0% -2.6
Patrick Sandoval 1.7% 4 2.8% 6.6 -1.1% -2.6
Alex Lange 0.0% 0 2.9% 2.6 -2.9% -2.6
Yonny Chirinos 1.8% 2 4.0% 4.5 -2.2% -2.5
Brad Hand 0.0% 0 2.9% 2.5 -2.9% -2.5
Jesús Luzardo 3.2% 9 4.0% 11.4 -0.8% -2.4
Bryan Baker 1.0% 1 3.2% 3.3 -2.2% -2.3
Framber Valdez 2.1% 6 2.9% 8.3 -0.8% -2.3
Jordan Montgomery 2.6% 7 3.4% 9.2 -0.8% -2.2
Luis Castillo 2.4% 6 3.2% 8.2 -0.9% -2.2

Gray and Dunning have both been very good, but when you face 200–250 major league batters, you expect someone to run into something, no matter if you’re Jacob deGrom-squared and had your elbow dipped in the river Styx as a baby. While many of the pitchers on this list still project to be stingy at allowing homers, a few, like Elder and Hand, have been hit hard at rates worse than even league average.

ZiPS HR Underachievers (6/1)
Name HR% HR zHR% zHR zHR% Diff zHR Diff
Yusei Kikuchi 6.2% 15 4.0% 9.7 2.2% 5.3
Josh Fleming 4.3% 9 2.0% 4.1 2.4% 4.9
Luis Medina 8.3% 10 4.4% 5.3 3.9% 4.7
Grayson Rodriguez 6.2% 13 4.0% 8.3 2.2% 4.7
José Ureña 9.7% 9 4.8% 4.5 4.9% 4.5
Ken Waldichuk 5.6% 14 3.8% 9.6 1.8% 4.4
Julio Urías 6.2% 14 4.4% 9.9 1.8% 4.1
Ross Stripling 6.8% 10 4.2% 6.2 2.6% 3.8
Colin Rea 4.5% 8 2.5% 4.4 2.1% 3.6
Luke Weaver 5.9% 11 4.0% 7.5 1.9% 3.5
Lance Lynn 5.0% 15 3.9% 11.7 1.1% 3.3
Tyler Wells 5.4% 13 4.0% 9.7 1.4% 3.3
Jose Suarez 7.3% 9 4.7% 5.8 2.6% 3.2
Corey Kluber 5.7% 11 4.1% 7.9 1.6% 3.1
Nick Lodolo 6.0% 10 4.2% 6.9 1.9% 3.1
Martín Perez 3.7% 10 2.6% 7.0 1.1% 3.0
Louie Varland 5.4% 9 3.7% 6.2 1.7% 2.8
Aaron Nola 4.0% 12 3.1% 9.3 0.9% 2.7
Chris Flexen 플렉센 4.1% 6 2.2% 3.3 1.9% 2.7
Zach Pop 7.1% 4 2.5% 1.4 4.7% 2.6
Eric Lauer 7.0% 13 5.6% 10.4 1.4% 2.6
David Peterson 4.4% 8 3.0% 5.4 1.4% 2.6
Jose Ruiz 4.8% 6 2.8% 3.5 2.0% 2.5
Tim Hill 4.1% 4 1.5% 1.5 2.6% 2.5
Austin Gomber 5.0% 12 4.0% 9.5 1.0% 2.5

Kikuchi’s home run rate should be mediocre, but 15 in 56 1/3 innings is an impressive un-achievement. He still projects to be unimpressive in this regard, but numbers this high, along with Medina’s 10 round-trippers surrendered in 27 2/3 innings, are unlikely to be true abilities going forward. ZiPS remains confused about how Fleming can allow so many homers with him being so hard to hit in the air, but he’s generally been an underachiever here, allowing more homers than ZiPS expects; projections reflect ZiPS being aware of this (whether it’s BABIP or xStats or zStats, the longer a pitcher outperforms or underperforms their data, the more predictive that difference is). Urías is a surprise giver-upper-of-homers given that he’s not getting hit all that hard all that often even while allowing those homers.

ZiPS BB Overachievers (6/1)
Name BB% BB zBB% zBB zBB% Diff zBB Diff
Framber Valdez 5.2% 15 8.7% 24.8 -3.4% -9.8
Zack Wheeler 5.5% 15 8.9% 24.4 -3.4% -9.4
Joel Payamps 3.7% 4 12.1% 12.9 -8.3% -8.9
Tyler Wells 5.0% 12 8.6% 20.7 -3.6% -8.7
Anthony DeSclafani 3.3% 9 6.2% 16.9 -2.9% -7.9
Cristian Javier 6.4% 16 9.4% 23.6 -3.0% -7.6
JP Sears 4.5% 11 7.0% 17.0 -2.5% -6.0
Tanner Bibee 6.3% 10 10.0% 15.8 -3.7% -5.8
Dean Kremer 6.7% 17 8.9% 22.6 -2.2% -5.6
Zac Gallen 5.5% 16 7.4% 21.4 -1.9% -5.4
Nathan Eovaldi 4.9% 14 6.8% 19.4 -1.9% -5.4
Matt Brash 8.7% 9 13.8% 14.3 -5.1% -5.3
Jesús Luzardo 7.1% 20 8.9% 25.2 -1.8% -5.2
J.P. France 6.8% 8 11.0% 12.9 -4.2% -4.9
Wade Miley 5.3% 9 8.1% 13.9 -2.9% -4.9
Ryan Tepera 6.5% 3 16.8% 7.7 -10.2% -4.7
Noah Syndergaard 3.9% 9 5.9% 13.6 -2.0% -4.6
Taj Bradley 4.1% 5 7.9% 9.6 -3.8% -4.6
José Alvarado 0.0% 0 8.8% 4.6 -8.8% -4.6
Jordan Montgomery 6.3% 17 8.0% 21.6 -1.7% -4.6
Josh Winckowski 5.1% 7 8.4% 11.5 -3.3% -4.5
Yennier Cano 1.0% 1 5.5% 5.5 -4.5% -4.5
Zach Eflin 3.4% 8 5.4% 12.5 -1.9% -4.5
Germán Márquez 3.8% 3 9.2% 7.4 -5.5% -4.4
Bryce Miller 2.2% 3 5.4% 7.3 -3.2% -4.3

Valdez is down about 40% from his career walk rate, and ZiPS just doesn’t see the justification there in his plate discipline stats. He’s getting off to more 0–1 counts, which is helpful, but batters remain skeptical of offering at his pitches relative to league average, and those pitchers tend to have higher walk rates than those who induce more swings. It’s also not a case of him being a habitual overperformer; he had 199 career zBB entering the season compared to 209 actual walks. I’m saddened that ZiPS doesn’t think Brash’s relative improvement is for real, but the the numbers are the numbers! If you feel that Wheeler hasn’t looked quite as sharp as his FIP suggests, this is one place that ZiPS agrees with you. Prior to 2023, he had reduced his zBB rate slightly every season.

ZiPS BB Underachievers (6/1)
Name BB% BB zBB% zBB zBB% Diff zBB Diff
Alek Manoah 15.0% 41 10.2% 27.8 4.8% 13.2
Ryan Feltner 15.2% 25 9.5% 15.6 5.7% 9.4
Tyler Anderson 10.5% 25 6.9% 16.5 3.6% 8.5
Brad Keller 19.9% 40 15.7% 31.6 4.2% 8.4
Shane McClanahan 9.6% 27 6.7% 18.8 2.9% 8.2
Spencer Strider 8.6% 22 5.5% 14.0 3.1% 8.0
MacKenzie Gore 11.3% 28 8.2% 20.3 3.1% 7.7
Marco Gonzales 8.4% 18 5.4% 11.7 2.9% 6.3
Tanner Scott 13.3% 14 7.6% 8.0 5.7% 6.0
Chris Bassitt 9.4% 26 7.3% 20.1 2.2% 5.9
Edward Cabrera 15.1% 35 12.7% 29.4 2.4% 5.6
Sandy Alcantara 8.5% 25 6.6% 19.4 1.9% 5.6
Johan Oviedo 11.2% 30 9.1% 24.5 2.1% 5.5
Ken Waldichuk 12.9% 32 10.7% 26.5 2.2% 5.5
Sean Manaea 11.4% 19 8.2% 13.7 3.2% 5.3
James Kaprielian 12.1% 22 9.2% 16.8 2.9% 5.2
Taijuan Walker 10.6% 26 8.4% 20.8 2.1% 5.2
Hobie Harris 13.8% 12 7.9% 6.8 5.9% 5.2
Daniel Bard 17.5% 11 9.3% 5.9 8.1% 5.1
Roansy Contreras 10.5% 23 8.1% 17.9 2.3% 5.1
Sam Moll 15.9% 13 9.7% 7.9 6.2% 5.1
Gerrit Cole 8.6% 26 7.0% 20.9 1.7% 5.1
Penn Murfee 16.7% 9 7.3% 4.0 9.3% 5.0
Martín Perez 7.4% 20 5.6% 15.0 1.8% 5.0
Merrill Kelly 9.9% 25 8.0% 20.1 1.9% 4.9

If you’re wondering what happened to Manoah, ZiPS is right there with you. It agrees that he should be allowing a lot more walks this year, as his first-strike and swing percentage numbers have eroded significantly since 2022’s breakout campaign. But 15% is a massive number, and zBB only gives a few pitchers every year a 15% or worse. Last year, there were only two: Huascar Brazoban and Touki Toussaint. A 10% walk rate for Manoah would be ugly but would also at least take some of the pain out of some wretched 2023 numbers.

ZiPS Strikeout Overachievers (6/1)
Name SO% SO zSO% zSO zSO% Diff zSO Diff
Kevin Gausman 32.9% 100 26.3% 79.9 6.6% 20.1
Hunter Greene 33.0% 88 27.5% 73.5 5.4% 14.5
Mitch Keller 30.4% 93 25.7% 78.6 4.7% 14.4
Merrill Kelly 27.4% 69 22.1% 55.6 5.3% 13.4
Logan Gilbert 28.7% 73 23.6% 59.9 5.2% 13.1
Zac Gallen 28.4% 82 24.1% 69.5 4.3% 12.5
Framber Valdez 26.9% 77 22.6% 64.6 4.3% 12.4
Andrew Heaney 24.3% 55 18.9% 42.7 5.4% 12.3
Taj Bradley 34.4% 42 25.4% 31.0 9.0% 11.0
Brad Hand 32.2% 28 20.1% 17.5 12.1% 10.5
Alexis Díaz 48.8% 41 36.6% 30.7 12.2% 10.3
Joe Ryan 29.1% 76 25.3% 66.0 3.8% 10.0
Clarke Schmidt 26.0% 65 22.0% 55.0 4.0% 10.0
Edward Cabrera 28.4% 66 24.2% 56.1 4.3% 9.9
Ron Marinaccio 29.8% 34 21.4% 24.4 8.4% 9.6
Seth Lugo 21.3% 38 16.3% 29.1 5.0% 8.9
Yennier Cano 30.0% 30 21.2% 21.2 8.8% 8.8
Lance Lynn 25.1% 76 22.2% 67.3 2.9% 8.7
Kyle Freeland 16.1% 43 12.8% 34.3 3.3% 8.7
Josh Hader 37.2% 32 27.2% 23.4 10.0% 8.6
Grayson Rodriguez 26.5% 56 22.5% 47.4 4.1% 8.6
Hunter Brown 28.8% 74 25.5% 65.6 3.3% 8.4
Drew Smith 28.4% 23 18.3% 14.8 10.1% 8.2
Bryan Baker 30.5% 32 22.8% 23.9 7.7% 8.1
Gerrit Cole 26.2% 79 23.6% 70.9 2.7% 8.1

I feel a bit betrayed by my creation, as I’ve been a habitual Gausman stan since he was a prospect with the Orioles, and I picked Greene as one of my pitcher breakouts this season. In the cause of Gausman, the culprit is obvious: his bump in strikeout rate has come despite his contact and swinging-strike rates being at their worst since 2018. ZiPS similarly doesn’t see Greene’s peripherals as having “earned” the additional strikeout a game. It’s also officially fallen out of love with Heaney after being a big proponent before 2022; he was the biggest HR underachiever in 2021.

ZiPS Strikeout Underachievers (6/1)
Name SO% SO zSO% zSO zSO% Diff zSO Diff
Shane Bieber 16.9% 53 22.4% 70.4 -5.6% -17.4
Tyler Anderson 13.8% 33 20.4% 48.8 -6.6% -15.8
Patrick Corbin 14.0% 42 18.9% 56.8 -4.9% -14.8
Gregory Soto 27.6% 27 41.8% 41.0 -14.3% -14.0
Patrick Sandoval 15.1% 36 20.6% 49.2 -5.5% -13.2
Roansy Contreras 16.4% 36 22.0% 48.4 -5.7% -12.4
Johan Oviedo 19.8% 53 24.1% 64.5 -4.3% -11.5
Shane McClanahan 29.1% 82 32.9% 92.9 -3.9% -10.9
Nick Martinez 19.4% 37 25.0% 47.8 -5.7% -10.8
Jose Suarez 17.1% 21 25.8% 31.7 -8.7% -10.7
Brock Stewart 29.9% 20 45.7% 30.6 -15.9% -10.6
Matthew Boyd 20.7% 44 25.6% 54.5 -4.9% -10.5
Dylan Dodd 10.8% 10 21.1% 19.6 -10.3% -9.6
Giovanny Gallegos 23.6% 21 34.3% 30.5 -10.7% -9.5
Ian Gibaut 20.6% 22 29.3% 31.3 -8.7% -9.3
Jon Gray 19.9% 46 23.6% 54.6 -3.7% -8.6
Connor Brogdon 19.7% 23 26.6% 31.2 -7.0% -8.2
Gregory Santos 21.3% 26 27.9% 34.1 -6.6% -8.1
Emmanuel Clase 17.7% 20 24.8% 28.0 -7.1% -8.0
Sandy Alcantara 20.5% 60 23.2% 68.0 -2.7% -8.0
Hobie Harris 10.3% 9 19.4% 16.9 -9.1% -7.9
Gavin Stone 8.5% 5 21.7% 12.8 -13.2% -7.8
Corbin Burnes 22.3% 59 25.2% 66.8 -2.9% -7.8
J.P. France 22.2% 26 28.6% 33.4 -6.3% -7.4
Ryan Weathers 15.8% 22 21.2% 29.4 -5.3% -7.4

While Bieber’s contact rates have ticked upwards, ZiPS doesn’t think that his strikeout rate ought to be this low. 22.4% wouldn’t exactly be a stunning turnaround for him — it would still be the worst season of his career — but at least it wouldn’t be more than half off where he was at his peak. Be less excited by Anderson’s inclusion here, as he’s the biggest career underachiever in strikeout rate, punching out 68 fewer batters than zSO has expected. Strikeouts of me in MLB The Show don’t count to his career stats, after all (the pause in his windup always drives me nuts).

ZiPS FIP Overachievers (6/1)
Name FIP FIP ER zFIP zFIP ER FIP Diff FIP ER Diff
Zac Gallen 2.09 16.9 3.36 27.1 -1.27 -10.3
Sonny Gray 2.20 14.7 3.49 23.4 -1.29 -8.6
Framber Valdez 2.94 23.5 3.88 31.0 -0.94 -7.5
Kevin Gausman 2.38 19.8 3.15 26.3 -0.77 -6.4
Bailey Ober 3.24 14.5 4.54 20.4 -1.30 -5.8
Brad Hand 2.01 4.5 4.42 10.0 -2.41 -5.4
Nathan Eovaldi 2.54 21.0 3.19 26.4 -0.65 -5.4
Bryce Miller 2.71 10.8 4.04 16.2 -1.33 -5.3
Yennier Cano 1.43 4.6 3.06 9.9 -1.63 -5.3
Mitch Keller 2.86 23.7 3.48 28.8 -0.62 -5.1
Chris Stratton 2.58 8.9 3.94 13.6 -1.36 -4.7
Michael Wacha 3.55 22.6 4.27 27.2 -0.72 -4.6
Dustin May 3.27 17.4 4.05 21.6 -0.78 -4.2
Bryce Elder 3.43 25.0 3.97 29.0 -0.54 -3.9
Adam Wainwright 4.47 13.1 5.77 16.9 -1.30 -3.8
Dane Dunning 2.83 15.1 3.53 18.8 -0.70 -3.7
Fernando Cruz 2.84 4.9 4.89 8.5 -2.05 -3.6
Cristian Javier 3.82 27.0 4.32 30.6 -0.50 -3.5
Logan Allen 2.94 13.0 3.71 16.3 -0.77 -3.4
Merrill Kelly 3.42 24.2 3.90 27.6 -0.48 -3.4
Andrew Wantz 3.29 7.9 4.62 11.1 -1.33 -3.2
Dauri Moreta 3.01 8.4 4.16 11.6 -1.15 -3.2
Josh Hader 2.35 5.8 3.63 9.0 -1.28 -3.2
Mark Leiter Jr. 3.42 8.6 4.67 11.8 -1.25 -3.1
Emilio Pagan 3.04 8.1 4.20 11.2 -1.16 -3.1

Since zStats have all the components of FIP, we can also derive our own version of FIP. I wouldn’t worry about Gallen being at the top of the list; he’s the anti-Tyler Anderson, in that he’s tended to be better than his peripheral stats think he should be. ZiPS largely ignores these given his history, which is why it has always been big on his future. All of the top four overachievers still look solid, just not as high in Cy Young contention. The pitchers that take the biggest hit are Ober and Wainwright, who both fall squarely into “meh” territory; unlike Gallen, neither has a history of beating their zStats.

ZiPS FIP Underachievers (6/1)
Name FIP FIP ER zFIP zFIP ER FIP Diff FIP ER Diff
Josh Fleming 5.88 31.8 4.02 21.7 1.86 10.1
José Ureña 10.98 22.4 6.54 13.3 4.44 9.0
Yusei Kikuchi 5.97 37.4 4.57 28.6 1.40 8.8
Alek Manoah 6.27 40.2 4.92 31.5 1.35 8.6
Martin Perez 5.01 34.0 3.74 25.4 1.27 8.6
Ken Waldichuk 7.02 39.5 5.51 31.0 1.51 8.5
Jose Suarez 8.22 22.2 5.19 14.0 3.03 8.2
Tyler Anderson 5.36 31.4 4.12 24.1 1.24 7.3
Chris Flexen 5.45 20.2 3.49 12.9 1.96 7.2
Corbin Burnes 4.55 32.2 3.54 25.1 1.01 7.1
Corey Kluber 6.6 30.6 5.08 23.5 1.52 7.0
Julio Urias 5.31 32.6 4.17 25.7 1.14 7.0
Matthew Boyd 4.84 26.0 3.59 19.3 1.25 6.7
Aaron Nola 4.4 36.5 3.59 29.8 0.81 6.7
Patrick Corbin 4.96 37.3 4.09 30.8 0.87 6.5
Chris Bassitt 5.22 38.5 4.35 32.1 0.87 6.4
Jon Gray 4.64 29.7 3.65 23.4 0.99 6.3
Ross Stripling 6.72 24.1 4.98 17.9 1.74 6.3
Luke Weaver 5.4 26.2 4.12 20.0 1.28 6.2
Shane Bieber 4.14 34.5 3.40 28.3 0.74 6.2
Jose Ruiz 6.44 18.6 4.31 12.5 2.13 6.2
Taijuan Walker 5.4 34.4 4.46 28.4 0.94 6.0
Colin Rea 5.37 25.3 4.12 19.4 1.25 5.9
Louie Varland 4.9 22.3 3.62 16.5 1.28 5.8
Lance Lynn 5.27 39.4 4.50 33.7 0.77 5.8

Sum it all up, and ZiPS takes the edge off at least some of the most disappointing early-season runs this year. Perez, Flexen, and Burnes all look more like themselves, and there’s at least some saving grace for Kikuchi and Manoah. Ureña only pitching like a Triple-A pitcher instead of a High-A once is at least something of a silver lining. As I said earlier, be skeptical of Anderson, and I’m instantly suspicious of anything that makes Corbin look good since his slider lost most of its bite.





Dan Szymborski is a senior writer for FanGraphs and the developer of the ZiPS projection system. He was a writer for ESPN.com from 2010-2018, a regular guest on a number of radio shows and podcasts, and a voting BBWAA member. He also maintains a terrible Twitter account at @DSzymborski.

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Bicycle Daze
9 months ago

I never knew you played MLB: The Show, Dan. Is your RTTS character named SzymbFace as suggested by one of your peers at FanGraphs?