Underthrown Pitches And The Pitchers Who Underthrow Them: Putting It All Together

Over the last several weeks, I’ve scoured Baseball Prospectus’ PitchF/x leaderboards for the league’s underthrown pitches. We’ve covered two different pitch types each week starting with four-seam fastballs and sinkers in the first installment, cutters and curves in the second, and sliders and changeups last week. This week, we put it all together. Now that we’ve identified the most underthrown pitches, who should consider overhauling his entire pitch mix to make the most of his electric stuff?

For a refresher on results and methodology, check the links below.

Vol 1: Four-seamers and Sinkers

Vol 2: Cutters and Curves

Vol 3: Sliders and Changeups

In an effort to be shall we say, less inert, I’ve done a few things differently this week. In addition to considering ground balls, pop-ups, and whiffs, I added an element of control in arriving at a Pitch Score. Specifically, I incorporated called strike-to-ball ratio. Over the last several weeks, I’ve waffled on whether to do this as many pitches, particularly the most effective out-pitches, are often purposely thrown outside of the zone. Think of a spiked curve or running slider.

Still, stealing called strikes is undeniably a desirable quality and should be incorporated at some point provided there’s a correlation with pitching outcomes. And it turns out there is.

Now, in the process of assessing pitch mix effectiveness, I also calculated Arsenal Scores. I’m certainly not the first to do this. Eno introduced arsenal scores almost a year and a half ago and Alex Chamberlain arguably improved upon them by weighting each pitch by frequency thrown. In previous articles in this series, I didn’t weight Z-scores differently based on their correlations as Eno did originally, nor by pitch frequency as Alex did subsequently. This time however, I’ve assigned weights based on a model regressing whiffs, grounds-plus-pop up rate, and called strike-to-ball ratio against Baseball Prospectus’ True Average statistic.

Correlations to True Average
Attribute Coefficient P-Value Adjusted Z-Score Weights
Whiffs per Swing -0.35786 1.97E-14 0.533
(GB + PU)/BIP -0.17683 8.05E-07 0.263
Called S/B -0.13675 3.18E-05 0.204
R2 = .3592

As for weighting based on pitch frequency, I made a conscious decision not to do so because this analysis is less concerned with “as-is” and more interested  in “what could be” if a pitcher threw his best offering at a frequency commensurate with its effectiveness.

Below you’ll find the pitchers who should consider a major overhaul to their pitch mix. For each pitcher, I’ve totaled the Underthrown Indexes (UI) of all offerings with a positive Pitch Score, ignoring any that graded out negatively. A negative Pitch Score results in a negative UI suggesting a pitch is actually overthrown. Any pitch with a positive UI should be thrown at the expense of one with a lower but preferably negative UI.

Additionally, because the denominator in UI is frequency, a negatively graded pitch thrown rarely will result in a more negative UI than the same ineffective pitch thrown too often. A very negative UI doesn’t mean the pitch is being thrown too often; on the contrary, it means that the pitcher, provided he chooses to throw a poor pitch at all, does so judiciously.

The Most Underthrowing Underthowers
Player 4-SM UI Sinker UI Cutter UI Curve UI Slider UI Change UI Arsenal UI
Corey Kluber -0.909 8.293 4.938 15.8 29.031
Trevor Cahill 1.54 5.105 12.18 5.798 24.624
Jacob deGrom 4.521 7.552 6.191 0.57 3.48 22.314
Ariel Miranda -0.404 18.844 2.552 21.397
Zack Greinke 1.052 5.182 8.939 2.815 2.223 20.21
Danny Salazar 1.85 -2.624 -1.084 15.564 2.657 20.071
Carlos Carrasco -1.247 -0.956 7.715 5.403 6.638 19.757
Tyler Chatwood 0.802 1.001 0.397 0.267 16.221 18.687
Jose Urena -2.098 18.229 0.28 -2.617 18.51
Marcus Stroman 1.511 15.261 0.685 0.445 17.903
Drew Pomeranz 0.471 17.226 0.024 17.721
Jon Lester -0.069 6.214 0.984 4.639 5.458 17.295
Kenta Maeda 0.19 8.626 0.45 4.518 3.216 -0.631 17.001
Matt Harvey -0.041 11.513 5.161 -2.022 -3.101 16.674
Max Scherzer 0.808 -9.112 5.968 7.515 14.291
Stephen Strasburg 0.23 5.749 -21.034 7.899 13.878
Zack Godley 0.082 -0.502 3.239 10.395 13.716
Jaime Garcia 0.215 3.213 2.807 -1.63 6.388 12.622
Chris Sale 2.218 3.96 1.323 5.104 12.605
Dallas Keuchel 2.863 0.106 5.904 3.437 12.31

A high Arsenal UI can be a function of two things. The first is a poor pitch mix; pitchers who underthrow their best offerings will have a high UI. Another factor that leads to a high Arsenal UI is overall arsenal quality. If a pitcher features four above average pitches, all four will yield positive UIs. So while Corey Kluber might bring down his Arsenal UI slightly by throwing his sinker less frequently in favor of his cutter, slider, or change, he’ll still feature an elevated aggregate Underthrown Index because the latter three pitches rank 1st, 4th, and 4th among their respective pitch types in Pitch Score; in other words, they’ll always be considered underthrown.

Takeaway #1: Corey Kluber is really good.

Takeaway #2: So is Trevor Cahill. Cahill features the league’s 3rd best curveball, 4th best slider, 10th best changeup, and 25th best sinker. That’s four, count ‘em, four elite or above average pitches from a 29-year old journeyman who’s spent time in the minor leagues each of the previous 4 seasons for non-rehab related reasons. In fact, Trevor Cahill leads the league in Arsenal Score. What I wouldn’t give for a second chance at my Bold Predictions right about now…

Now, those pitches also happen to be the league’s 12th, 3rd, 12th, and 32nd most underthrown pitches within their respective classifications. Like Kluber, Cahill is another example of a pitcher whose high UI is supported not by poor pitch selection but rather by a robust and effective arsenal. Having just made his second rehab start last night in his return from a shoulder strain, this is likely your last opportunity to buy.

In a two-start span against the Brewers and Rangers, Jacob deGrom allowed 15 earned runs, 6 walks, and 4 homers in just 8 innings. He watched his ERA balloon from 3.23 to 4.75. He’s also been spectacular since. Over his last three starts, deGrom has averaged 8.1 innings, a 0.72 ERA, and 54.7% ground ball rate. Now, it’s worth mentioning he’s also stranded 99% of his base runners and benefited from a .156 BABIP.

But regardless of whatever peaks and valleys owners may endure with deGrom, the fact is that he boasts one of the best arsenals in the game. And it’s one that could be made even better by throwing his sinker and curve more often at the expense of his slider. The former rank 8th and 26th among their respective pitch types while his slider ranks just 48th. And what do you know, that’s exactly what he’s done since those two blow-up starts just a couple weeks ago.

Source: Brooks Baseball

Whether this trend continues is anyone’s guess, however deGrom has to be encouraged by the results his last three times out.

I mentioned Ariel Miranda’s slider last week. For an extreme fly-ball pitcher who doesn’t miss many bats, a pitch that generates grounders, pop-ups, and whiffs should be an often-pulled arrow from his quiver. This is especially true given the rest of his arsenal’s mediocrity. Miranda’s slider ranks 23rd in whiffs per swing and 3rd in grounders-plus-pop ups per ball-in-play combining to give him the 14th best slider in the game. He should also consider leaning on his changeup a bit more as well as it ranks 35th out of 140 qualified change pieces. Really, Miranda should throw anything that keeps the ball out of Safeco’s outfield bleachers and both his slider and change do just that.

Between injuries, inconsistency, and  adolescent crushes made very public, we’ve yet to see the Matt Harvey of old. Sadly, we may never see him again (although if you’re partying in Montauk these days, there’s a good chance you already have). The list of successful returns from the ailment that plagued him is and remains depressingly short.

Harvey’s Arsenal Score ranks 89th out of 211 qualified pitchers. That he continues to throw a slider and changeup that rank 93rd and 104th among their respective pitch types nearly 35% of the time hasn’t done him any favors. Harvey has also given up an uncharacteristically high number of homers this year.

Perhaps leaning more heavily on his sinker and curveball, both of which he rarely throws, would help him generate more ground balls and pop-ups. We may never see The Dark Knight rise again, however that doesn’t mean Harvey can’t reinvent himself as a contact-manager and, health willing, still lead a productive career.

There are plenty of pitchers who could benefit from altering their pitch mix a bit. Danny Salazar should consider incorporating his slider a bit more. I’d say the same of Max Scherzer and Dallas Keuchel but whatever they’re doing appears to be working just fine.

Marcus Stroman and Drew Pomeranz should go back to their cutters. Both are elite at inducing whiffs and better than average at burning worms. Stroman’s will also steal called strikes as well.

Zack Godley and Tyler Chatwood could each stand to throw more changeups. Godley already features top-10 swinging strike and ground ball rates so it’s scary to think what a few more changeups at the expense of his cutter could do.

Chatwood doesn’t boast nearly the arsenal that Godley does but his changeup is every bit as good, if not better. He’s had issues with homers and throwing his changeup a bit more could take care of that.

I had planned to talk about Arsenal Scores but I think that might deserve its own article so look for that next week. Still, in case you might find it useful, I’ve included a list of the Top 100 arsenals following the UI leaderboard. How crazy is it that Brandon Finnegan, who only threw one pitch that qualified for this exercise sits in the Top 10? By Pitch Score his sinker has been the best pitch in baseball by a YUGE margin. Here’s hoping for a speedy recovery. Again.

Top 100 Underthowers
Player 4-SM UI Sinker UI Cutter UI Curve UI Slider UI Change UI Arsenal UI
Corey Kluber -0.909 8.293 4.938 15.800 29.031
Trevor Cahill 1.540 5.105 12.180 5.798 24.624
Jacob deGrom 4.521 7.552 6.191 0.570 3.480 22.314
Ariel Miranda -0.404 18.844 2.552 21.397
Zack Greinke 1.052 5.182 8.939 2.815 2.223 20.210
Danny Salazar 1.850 -2.624 -1.084 15.564 2.657 20.071
Carlos Carrasco -1.247 -0.956 7.715 5.403 6.638 19.757
Tyler Chatwood 0.802 1.001 0.397 0.267 16.221 18.687
Jose Urena -2.098 18.229 0.280 -2.617 18.510
Marcus Stroman 1.511 15.261 0.685 0.445 17.903
Drew Pomeranz 0.471 17.226 0.024 17.721
Jon Lester -0.069 6.214 0.984 4.639 5.458 17.295
Kenta Maeda 0.190 8.626 0.450 4.518 3.216 -0.631 17.001
Matt Harvey -0.041 11.513 5.161 -2.022 -3.101 16.674
Max Scherzer 0.808 -9.112 5.968 7.515 14.291
Stephen Strasburg 0.230 5.749 -21.034 7.899 13.878
Zack Godley 0.082 -0.502 3.239 10.395 13.716
Jaime Garcia 0.215 3.213 2.807 -1.630 6.388 12.622
Chris Sale 2.218 3.960 1.323 5.104 12.605
Dallas Keuchel 2.863 0.106 5.904 3.437 12.310
Tim Adleman 1.299 -2.654 10.297 0.138 11.735
Jeff Hoffman 0.096 3.430 8.093 11.619
Zack Wheeler 0.252 2.501 -6.306 -1.270 8.838 11.591
Noah Syndergaard 0.619 4.239 6.647 11.505
Daniel Norris -0.760 7.033 -0.556 4.336 11.369
Mike Pelfrey -0.265 11.282 -7.817 11.282
Sonny Gray 1.322 6.196 -0.524 3.143 -4.719 10.661
Blake Snell -0.557 3.584 5.432 0.960 9.976
Rick Porcello 0.560 -0.651 8.272 -3.659 -5.798 0.941 9.773
Jacob Faria 1.016 -0.492 8.677 9.694
Sean Manaea 1.006 3.144 5.395 9.545
Jimmy Nelson 1.715 2.461 5.016 -5.244 9.192
Jeff Samardzija 2.406 0.720 2.854 3.197 -0.197 9.176
Jhoulys Chacin -0.254 7.360 1.769 -21.891 9.129
Masahiro Tanaka -1.260 -5.999 8.022 0.952 8.974
Brandon Finnegan 8.804 8.804
Randall Delgado 3.410 2.200 3.124 8.734
Jose Quintana 0.660 -1.219 1.091 6.697 8.448
Joe Musgrove 1.335 2.230 4.857 -1.669 -1.077 8.422
James Paxton 1.827 3.187 3.255 8.269
Hyun-jin Ryu 0.822 3.315 3.546 0.527 8.211
Charlie Morton 0.053 4.730 3.223 8.006
Trevor Williams 0.928 7.074 -3.840 -2.631 8.002
Aaron Nola 1.777 0.000 0.883 5.339 7.998
Alex Wood 2.910 2.799 2.179 7.888
Carlos Martinez 1.081 2.454 2.939 1.208 7.681
Daniel Gossett 2.655 4.818 7.472
Robbie Ray 2.312 -1.579 4.461 0.620 7.393
Mike Clevinger 0.031 0.918 4.097 2.215 7.261
Chase Anderson 1.341 -0.814 -2.921 3.103 2.430 6.874
Ian Kennedy -0.129 3.193 0.582 2.776 6.550
Jordan Montgomery -2.315 1.325 5.222 -0.149 -0.231 6.547
Yu Darvish 1.539 0.787 2.645 1.487 -0.478 6.458
Johnny Cueto -1.547 1.450 1.765 -7.472 3.152 6.367
Michael Fulmer 0.793 0.890 -2.211 4.661 6.344
Adam Conley -0.457 2.327 3.907 6.234
Tyler Glasnow -0.815 -2.403 0.307 5.569 5.876
Mike Fiers 2.914 -0.225 -3.102 0.282 -13.160 2.623 5.820
Lance Lynn 1.325 1.992 2.439 -26.112 5.755
Alec Asher 1.708 -5.176 3.846 5.554
Jake Arrieta 0.814 4.632 -4.925 -2.925 5.446
Trevor Bauer 0.099 -2.524 4.100 1.175 -2.652 5.374
Lance McCullers 0.463 1.287 1.462 2.091 5.303
Madison Bumgarner -0.188 1.685 3.431 5.116
David Price 1.520 1.541 1.903 4.964
Jeff Locke -3.910 -2.273 4.896 4.896
Jameson Taillon 1.709 2.916 0.272 -11.455 4.896
Gio Gonzalez -0.247 -0.914 2.910 1.948 4.858
Dinelson Lamet -0.947 1.486 3.118 4.604
Chad Kuhl 0.349 4.198 -3.201 4.547
CC Sabathia 1.715 -1.289 -0.570 2.817 4.532
Jake Junis -0.309 1.085 3.442 4.528
Ben Lively 4.455 -6.693 -3.668 4.455
Jose Berrios 3.856 -0.171 0.409 -6.394 4.265
Chris Archer 0.060 0.609 3.554 4.223
Alex Meyer 1.816 -1.965 2.216 4.032
David Paulino -1.740 -2.827 3.929 0.026 3.955
Michael Wacha 1.027 -0.186 1.955 0.961 3.944
Clayton Kershaw 0.499 1.638 1.753 3.890
Nate Karns -1.119 -15.377 2.322 1.564 3.886
Matt Garza -1.830 0.470 -3.224 3.266 -2.857 3.736
Brandon McCarthy 3.682 -0.395 -0.061 3.682
Mat Latos 3.615 3.615
Jordan Zimmermann -1.122 3.562 -3.694 -2.304 -23.521 3.562
Joe Biagini 0.901 -7.960 2.528 -0.867 3.430
Tyler Anderson -0.706 2.372 0.966 3.338
Mike Bolsinger -1.556 -0.653 3.256 3.256
Matt Boyd -2.182 -1.636 2.166 -3.364 -14.296 1.088 3.254
Danny Duffy -2.065 1.664 0.198 1.359 3.222
Buck Farmer 3.066 3.066
Francisco Liriano -1.189 2.031 1.000 3.030
Tommy Milone 2.962 -2.399 -0.315 2.962
Tanner Roark -6.595 -0.182 1.022 -1.688 1.938 2.959
Jharel Cotton 0.374 -3.071 2.566 -8.289 -1.012 2.940
Luis Perdomo 0.214 2.724 2.938
Rafael Montero 2.901 2.901
Lisalverto Bonilla 1.767 1.123 2.889
J.A. Happ 1.417 1.464 -9.230 -1.391 2.881
Kyle Hendricks 2.102 0.770 -32.509 -0.121 2.871
James Shields 0.197 2.515 2.712

 

Top 100 Arsenals
Player 4-Seamer Sinker Cutter Curveball Slider Changeup Arsenal Score
Trevor Cahill 0.591 1.250 1.204 1.052 4.096
Jacob deGrom 1.875 1.111 0.601 0.134 0.369 4.090
Corey Kluber -0.306 1.774 1.238 1.162 3.868
Dallas Keuchel 1.305 0.012 1.214 0.437 2.968
Chris Sale 0.766 0.579 0.381 1.127 2.852
Brandon Finnegan 2.742 2.742
Zack Greinke 0.450 0.370 0.884 0.722 0.306 2.732
Alex Wood 1.450 0.693 0.528 2.672
Sean Manaea 0.562 0.617 1.324 2.502
Carlos Carrasco -0.519 -0.110 1.085 0.958 0.998 2.412
Noah Syndergaard 0.258 0.880 1.237 2.376
Robbie Ray 1.226 -0.096 1.031 0.100 2.260
Jaime Garcia 0.071 0.954 0.196 -0.196 1.157 2.181
James Paxton 1.146 0.332 0.646 2.124
Max Scherzer 0.406 -0.799 1.567 0.928 2.101
Zack Godley 0.030 -0.108 0.969 1.192 2.084
Danny Salazar 0.734 -0.457 -0.063 1.031 0.810 2.054
Jon Lester -0.027 0.688 0.266 0.649 0.465 2.042
Carlos Martinez 0.283 0.753 0.804 0.184 2.024
Kenta Maeda 0.052 0.687 0.094 0.598 0.618 -0.073 1.975
Sonny Gray 0.429 1.573 -0.093 0.454 -0.430 1.933
Marcus Stroman 0.822 0.790 0.066 0.084 1.762
Randall Delgado 0.613 0.385 0.677 1.675
Daniel Gossett 0.552 1.096 1.648
Jacob Faria 0.590 -0.122 1.145 1.613
Aaron Nola 0.509 0.000 0.274 0.799 1.582
Hyun-jin Ryu 0.322 0.489 0.605 0.140 1.555
Tyler Chatwood 0.256 0.300 0.046 0.056 0.882 1.541
Jeff Hoffman 0.064 0.636 0.751 1.451
Jimmy Nelson 0.570 0.825 0.786 -0.751 1.430
Charlie Morton 0.026 0.484 0.875 1.385
Lance McCullers 0.084 0.293 0.660 0.289 1.327
Stephen Strasburg 0.124 1.284 -1.476 1.343 1.275
Drew Pomeranz 0.239 0.994 0.010 1.242
Jeff Samardzija 0.462 0.214 0.191 0.400 -0.036 1.232
Mike Clevinger 0.017 0.111 0.739 0.347 1.213
Jose Berrios 1.555 -0.041 0.115 -0.497 1.132
Tim Adleman 0.579 -0.574 1.094 0.030 1.129
Clayton Kershaw 0.235 0.272 0.579 1.087
David Price 0.504 0.311 0.247 1.062
Blake Snell -0.314 0.365 0.803 0.179 1.032
Luis Perdomo 0.126 0.901 1.027
Mat Latos 1.019 1.019
Luis Severino 0.583 0.457 -0.029 1.011
Brandon McCarthy 1.110 -0.120 -0.013 0.978
Yu Darvish 0.526 0.120 0.394 0.065 -0.130 0.975
Jake Junis -0.153 0.172 0.953 0.972
Ariel Miranda -0.243 0.830 0.378 0.964
Madison Bumgarner -0.095 0.471 0.582 0.958
Michael Fulmer 0.245 0.256 -0.468 0.895 0.927
Jordan Montgomery -0.493 0.276 1.208 -0.021 -0.048 0.922
Michael Wacha 0.541 -0.031 0.210 0.177 0.897
Trevor Williams 0.481 1.328 -0.630 -0.293 0.887
Alex Meyer 0.574 -0.554 0.855 0.875
Jose Quintana 0.278 -0.246 0.328 0.506 0.866
Chad Kuhl 0.216 0.998 -0.357 0.858
Chase Anderson 0.421 -0.161 -0.387 0.535 0.446 0.854
Ian Kennedy -0.079 0.371 0.076 0.381 0.749
Lisalverto Bonilla 0.371 0.358 0.729
Tyler Skaggs 0.494 0.231 0.725
Adam Conley -0.307 0.399 0.609 0.701
Daniel Norris -0.411 0.667 -0.129 0.573 0.700
Dan Straily 0.466 0.235 -0.003 0.698
Rafael Montero 0.697 0.697
Jameson Taillon 0.455 1.153 0.068 -1.002 0.674
Gio Gonzalez -0.091 -0.224 0.637 0.330 0.653
Buck Farmer 0.642 0.642
Eduardo Rodriguez 0.314 -0.069 0.373 0.619
Joe Musgrove 0.509 0.252 0.435 -0.452 -0.127 0.618
Lance Lynn 0.578 0.691 0.342 -1.014 0.597
Doug Fister 0.545 0.545
Chris Archer 0.028 0.283 0.214 0.525
James Shields 0.060 0.461 0.521
Tyler Anderson -0.311 0.504 0.308 0.500
Casey Lawrence 0.484 0.484
Johnny Cueto -0.530 0.247 0.458 -0.287 0.590 0.477
Mike Pelfrey -0.157 1.435 -0.803 0.476
Rich Hill 0.845 -0.381 0.464
Michael Pineda 0.294 0.606 -0.471 0.429
Brad Peacock -0.553 0.981 0.428
Sean Newcomb 0.415 0.415
Dinelson Lamet -0.459 0.486 0.384 0.411
CC Sabathia 0.410 -0.349 -0.172 0.517 0.406
Francisco Liriano -0.511 0.695 0.190 0.374
Edinson Volquez -0.047 -0.174 0.540 0.319
Trevor Bauer 0.040 -0.349 0.457 0.325 -0.161 0.312
Taijuan Walker 1.046 -0.245 -0.493 0.308
Luis Cessa 0.297 0.297
Matt Harvey -0.021 0.695 0.452 -0.450 -0.379 0.297
Aaron Sanchez 0.633 -0.353 0.280
Jake Arrieta 0.450 0.773 -0.721 -0.233 0.270
Junior Guerra 0.457 -0.053 -0.136 0.268
Andrew Triggs 0.646 -0.256 -0.148 0.242
J.C. Ramirez -0.167 0.340 0.025 0.198
J.A. Happ 0.649 0.397 -0.721 -0.197 0.128
Mike Fiers 0.809 -0.030 -0.479 0.054 -0.729 0.493 0.119
Justin Nicolino 0.086 0.011 0.097
Danny Duffy -0.589 0.312 0.058 0.306 0.088
Nik Turley 0.085 0.085
Erasmo Ramirez 0.449 -0.135 -0.241 0.073



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Rylan writes for Fangraphs and The Hardball Times. Look for his weekly Deep League Waiver Wire and The Chacon Zone columns this season.

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ccoville
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ccoville

That arsenal chart suddenly has me concerned about Duffy.

johansantana17
Member
johansantana17

It also lists Tim Adleman above Clayton Kershaw, so it should probably be taken with a very large grain of salt.