About a month ago, I started searching for the league’s underthrown pitches. Pitches that despite inducing elite swing-and-miss, ground ball, and pop-up rates, are thrown with scarcity relative to other inferior offerings. It was as an enlightening a topic to research, as it dealt with untapped potential, as it was a fun series to write. Though to be honest, there wasn’t a whole lot of actionable fantasy advice to be gleamed. But in the process of writing those pieces, I had to grade each pitch. And arsenal scores, a subject of interest to the RotoGraphs community over the years, were just a stone’s throw from away from the groundwork I’d already laid.



The pitch grades I used were comprised of three components converted into Z-Scores: whiffs, ground balls plus pop-ups, and called strike-to-ball ratio. To each Z-Score, I applied weights (below) based off a linear model and summed them to arrive at an overall Arsenal Score. I’ve provided two sets of results, one in which each pitch is weighted evenly and another that weights each offering based on frequency thrown. I’ve pretty much taken the work that Eno and Alex had done previously, added an element of control, and refined the weighting based on a correlation between the aforementioned components and Baseball Prospectus’ True Average.

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

While there are strong correlations between the outcomes evaluated (whiffs, ground balls, pop-ups, and called strikes), there is still a significant amount of the variation left unaccounted for. Perhaps, not unrelated, we’re still at the point where we depend on outcomes to evaluate pitches, relying on hitters’ decisions and talents instead of an offering’s innate qualities alone. These are some of the drawbacks with this methodology.

One other thing before we look into a few of the interesting names to make the list: it’s too exhausting to keep scraping the PitchF/x leaderboards for each article so this data is, admittedly, a week old. The table below doesn’t account for Clayton Kershaw’s recent outing against the Diamondbacks during which he struck out 11 nor does it include Jon Gray’s latest turns since his activation, though in fairness Gray still would fall short of the 50 pitch threshold on half his repertoire.

Still, in the never-ending quest to separate talent from results, this is a helpful exercise and one that I hope you can find use for.

Top 150 Arsenals Player 4-Sm Sinker Cutter Curve Slider Change Pitches Rk Unweighted Arsenal wRk Frequency-weighted Arsenal Jacob deGrom 1.875 1.111 0.601 0.134 0.369 5 2 4.090 1 1.070 Alex Wood 1.450 0.693 0.528 3 8 2.672 2 1.023 Dallas Keuchel 1.305 0.012 1.214 0.437 4 4 2.968 3 0.901 Robbie Ray 1.226 -0.096 1.031 0.100 4 12 2.260 4 0.898 James Paxton 1.146 0.332 0.646 3 14 2.124 5 0.881 Brandon Finnegan 2.742 1 6 2.742 6 0.854 Trevor Cahill 0.591 1.250 1.204 1.052 4 1 4.096 7 0.842 Sean Manaea 0.562 0.617 1.324 3 9 2.502 8 0.760 Chris Sale 0.766 0.579 0.381 1.127 4 5 2.852 9 0.707 Corey Kluber -0.306 1.774 1.238 1.162 4 3 3.868 10 0.672 Max Scherzer 0.406 -0.799 1.567 0.928 4 15 2.101 11 0.660 Jose Berrios 1.555 -0.041 0.115 -0.497 4 37 1.132 12 0.611 Carlos Martinez 0.283 0.753 0.804 0.184 4 19 2.024 13 0.553 Sonny Gray 0.429 1.573 -0.093 0.454 -0.430 5 21 1.933 14 0.549 Zack Greinke 0.450 0.370 0.884 0.722 0.306 5 7 2.732 15 0.534 Danny Salazar 0.734 -0.457 -0.063 1.031 0.810 5 17 2.054 16 0.523 Noah Syndergaard 0.258 0.880 1.237 3 11 2.376 17 0.521 Marcus Stroman 0.822 0.790 0.066 0.084 4 22 1.762 18 0.510 Jaime Garcia 0.071 0.954 0.196 -0.196 1.157 5 13 2.181 19 0.506 Jameson Taillon 0.455 1.153 0.068 -1.002 4 65 0.674 20 0.506 Taijuan Walker 1.046 -0.245 -0.493 3 87 0.308 21 0.504 Lance Lynn 0.578 0.691 0.342 -1.014 4 70 0.597 22 0.501 Jimmy Nelson 0.570 0.825 0.786 -0.751 4 30 1.430 23 0.481 Stephen Strasburg 0.124 1.284 -1.476 1.343 4 33 1.275 24 0.478 Luis Severino 0.583 0.457 -0.029 3 44 1.011 25 0.472 Jacob Faria 0.590 -0.122 1.145 3 25 1.613 26 0.463 Lance McCullers 0.084 0.293 0.660 0.289 4 32 1.327 27 0.420 Zack Godley 0.030 -0.108 0.969 1.192 4 16 2.084 28 0.415 Kendall Graveman 0.615 -0.175 -0.487 3 111 -0.047 29 0.395 Luis Perdomo 0.126 0.901 2 42 1.027 30 0.372 Doug Fister 0.545 1 71 0.545 31 0.365 Daniel Gossett 0.552 1.096 2 24 1.648 32 0.364 Trevor Williams 0.481 1.328 -0.630 -0.293 4 53 0.887 33 0.363 Tyler Skaggs 0.494 0.231 2 60 0.725 34 0.361 Alex Meyer 0.574 -0.554 0.855 3 54 0.875 35 0.355 Aaron Nola 0.509 0.000 0.274 0.799 4 26 1.582 36 0.351 Vincent Velasquez 0.725 -0.510 -0.190 -0.736 4 153 -0.711 37 0.348 Clayton Kershaw 0.235 0.272 0.579 3 39 1.087 38 0.348 Hyun-jin Ryu 0.322 0.489 0.605 0.140 4 27 1.555 39 0.339 Michael Wacha 0.541 -0.031 0.210 0.177 4 52 0.897 40 0.335 Chad Kuhl 0.216 0.998 -0.357 3 56 0.858 41 0.332 Randall Delgado 0.613 0.385 0.677 3 23 1.675 42 0.324 J.A. Happ 0.649 0.397 -0.721 -0.197 4 95 0.128 43 0.321 Michael Pineda 0.294 0.606 -0.471 3 79 0.429 44 0.317 Brad Peacock -0.553 0.981 2 80 0.428 45 0.308 Charlie Morton 0.026 0.484 0.875 3 31 1.385 46 0.300 Dan Straily 0.466 0.235 -0.003 3 63 0.698 47 0.297 Brandon McCarthy 1.110 -0.120 -0.013 3 45 0.978 48 0.296 Mat Latos 1.019 1 43 1.019 49 0.287 Kenta Maeda 0.052 0.687 0.094 0.598 0.618 -0.073 6 20 1.975 50 0.278 Eduardo Rodriguez 0.314 -0.069 0.373 3 68 0.619 51 0.270 Jon Lester -0.027 0.688 0.266 0.649 0.465 5 18 2.042 52 0.268 Rich Hill 0.845 -0.381 2 78 0.464 53 0.264 David Price 0.504 0.311 0.247 3 40 1.062 54 0.262 Tim Adleman 0.579 -0.574 1.094 0.030 4 38 1.129 55 0.257 Aaron Sanchez 0.633 -0.353 2 90 0.280 56 0.255 Jake Arrieta 0.450 0.773 -0.721 -0.233 4 91 0.270 57 0.254 Carlos Carrasco -0.519 -0.110 1.085 0.958 0.998 5 10 2.412 58 0.244 Tyler Chatwood 0.256 0.300 0.046 0.056 0.882 5 28 1.541 59 0.237 Joe Biagini 0.424 -0.808 0.595 -0.139 4 101 0.072 60 0.235 Rookie Davis 0.705 -0.903 0.051 3 118 -0.148 61 0.232 Jeff Hoffman 0.064 0.636 0.751 3 29 1.451 62 0.230 Yu Darvish 0.526 0.120 0.394 0.065 -0.130 5 46 0.975 63 0.224 Chase Anderson 0.421 -0.161 -0.387 0.535 0.446 5 57 0.854 64 0.223 Michael Fulmer 0.245 0.256 -0.468 0.895 4 50 0.927 65 0.222 Casey Lawrence 0.484 1 75 0.484 66 0.219 Jordan Montgomery -0.493 0.276 1.208 -0.021 -0.048 5 51 0.922 67 0.219 Jake Junis -0.153 0.172 0.953 3 47 0.972 68 0.216 Mike Clevinger 0.017 0.111 0.739 0.347 4 36 1.213 69 0.210 Mike Fiers 0.809 -0.030 -0.479 0.054 -0.729 0.493 6 96 0.119 70 0.210 Jeff Samardzija 0.462 0.214 0.191 0.400 -0.036 5 35 1.232 71 0.209 Jose Quintana 0.278 -0.246 0.328 0.506 4 55 0.866 72 0.205 Lisalverto Bonilla 0.371 0.358 2 59 0.729 73 0.192 Junior Guerra 0.457 -0.053 -0.136 3 92 0.268 74 0.183 Madison Bumgarner -0.095 0.471 0.582 3 49 0.958 75 0.182 Drew Pomeranz 0.239 0.994 0.010 3 34 1.242 76 0.182 Kyle Hendricks 0.514 0.360 -1.934 -0.028 4 167 -1.087 77 0.173 Rafael Montero 0.697 1 64 0.697 78 0.167 Andrew Triggs 0.646 -0.256 -0.148 3 93 0.242 79 0.162 Chris Archer 0.028 0.283 0.214 3 72 0.525 80 0.158 Jhoulys Chacin -0.097 0.790 0.537 -1.293 4 113 -0.063 81 0.135 Buck Farmer 0.642 1 67 0.642 82 0.134 Joe Musgrove 0.509 0.252 0.435 -0.452 -0.127 5 69 0.618 83 0.124 Matt Andriese 0.209 -0.285 -0.222 0.318 4 106 0.020 84 0.111 Gio Gonzalez -0.091 -0.224 0.637 0.330 4 66 0.653 85 0.107 James Shields 0.060 0.461 2 73 0.521 86 0.103 Sean Newcomb 0.415 1 81 0.415 87 0.100 Trevor Bauer 0.040 -0.349 0.457 0.325 -0.161 5 86 0.312 88 0.099 A.J. Griffin 0.147 0.196 -0.302 3 104 0.041 89 0.098 Luis Cessa 0.297 1 88 0.297 90 0.095 Edinson Volquez -0.047 -0.174 0.540 3 85 0.319 91 0.087 Alec Asher 0.714 -1.289 0.643 3 102 0.069 92 0.085 Shelby Miller 0.108 0.566 -0.744 3 114 -0.070 93 0.082 Johnny Cueto -0.530 0.247 0.458 -0.287 0.590 5 76 0.477 94 0.078 Clayton Richard 0.348 -0.220 -0.581 3 133 -0.453 95 0.074 Nate Karns -0.463 -1.169 0.863 0.216 4 137 -0.553 96 0.070 Tyler Anderson -0.311 0.504 0.308 3 74 0.500 97 0.068 Ian Kennedy -0.079 0.371 0.076 0.381 4 58 0.749 98 0.057 Francisco Liriano -0.511 0.695 0.190 3 84 0.374 99 0.054 Marco Estrada 0.149 -0.841 -0.645 0.244 4 168 -1.093 100 0.052 CC Sabathia 0.410 -0.349 -0.172 0.517 4 83 0.406 101 0.047 Jharel Cotton 0.109 -0.501 0.705 -0.780 -0.180 5 148 -0.646 102 0.039 Erasmo Ramirez 0.449 -0.135 -0.241 3 100 0.073 103 0.035 Justin Nicolino 0.086 0.011 2 97 0.097 104 0.035 Nik Turley 0.085 1 99 0.085 105 0.028 Jacob Turner 0.035 1 105 0.035 106 0.021 Jake Odorizzi 0.324 -0.557 -1.052 3 177 -1.284 107 0.020 Zack Wheeler 0.109 0.501 -0.781 -0.252 0.398 5 109 -0.026 108 0.018 Blake Snell -0.314 0.365 0.803 0.179 4 41 1.032 109 0.012 Mike Pelfrey -0.157 1.435 -0.803 3 77 0.476 110 0.007 Jason Vargas 0.001 -0.485 -0.287 0.602 4 120 -0.169 111 0.007 Tommy Milone 0.459 -0.330 -0.080 3 103 0.049 112 0.005 Ben Lively 1.107 -1.182 -0.475 3 136 -0.550 113 0.005 J.C. Ramirez -0.167 0.340 0.025 3 94 0.198 114 0.003 Mike Montgomery -0.113 0.115 2 107 0.002 115 0.000 R.A. Dickey -0.077 1 115 -0.077 116 -0.008 Masahiro Tanaka -0.310 -0.540 0.534 0.272 4 110 -0.044 117 -0.011 Brian Johnson 0.097 -0.250 2 119 -0.153 118 -0.013 John Lackey 0.404 -0.308 -0.466 -0.205 -0.597 5 170 -1.172 119 -0.014 Gerrit Cole 0.217 -0.440 -0.550 0.322 -0.104 5 138 -0.556 120 -0.016 Kyle Freeland -0.137 0.119 0.175 -0.257 -0.607 5 150 -0.706 121 -0.016 Dinelson Lamet -0.459 0.486 0.384 3 82 0.411 122 -0.016 Chase DeJong -0.106 1 116 -0.106 123 -0.016 Ty Blach 0.304 -0.979 -1.469 -0.095 4 199 -2.239 124 -0.019 Francis Martes -0.052 1 112 -0.052 125 -0.020 Danny Duffy -0.589 0.312 0.058 0.306 4 98 0.088 126 -0.023 Adam Conley -0.307 0.399 0.609 3 61 0.701 127 -0.043 Patrick Corbin -0.461 -0.598 0.861 -0.450 4 149 -0.648 128 -0.047 Ariel Miranda -0.243 0.830 0.378 3 48 0.964 129 -0.054 Rick Porcello 0.156 -0.208 0.733 -0.563 -0.340 0.096 6 117 -0.127 130 -0.055 Austin Bibens-Dirkx 0.426 -1.055 -0.281 3 160 -0.909 131 -0.064 Parker Bridwell -0.252 1 123 -0.252 132 -0.065 Wei-Yin Chen -0.082 -0.495 0.283 3 126 -0.295 133 -0.072 Matt Harvey -0.021 0.695 0.452 -0.450 -0.379 5 89 0.297 134 -0.075 Wade Miley -0.713 0.218 0.024 0.012 0.193 5 124 -0.268 135 -0.077 Alex Cobb -0.373 0.159 2 122 -0.214 136 -0.101 Julio Teheran 0.071 -0.244 -0.096 0.056 -0.990 5 172 -1.203 137 -0.105 Braden Shipley -0.384 1 130 -0.384 138 -0.108 Daniel Norris -0.411 0.667 -0.129 0.573 4 62 0.700 139 -0.114 Asher Wojciechowski -0.536 1 135 -0.536 140 -0.118 Felix Hernandez -0.934 0.435 -0.069 3 140 -0.568 141 -0.121 Yovani Gallardo -0.025 0.288 -0.370 -0.320 -0.394 5 155 -0.820 142 -0.122 Jeff Locke -1.170 -0.346 1.172 3 129 -0.344 143 -0.122 Scott Feldman 0.088 -0.199 -0.257 -0.341 4 151 -0.709 144 -0.124 Mike Foltynewicz -0.072 -0.314 -0.029 -0.121 0.123 5 131 -0.413 145 -0.124 Hisashi Iwakuma -0.319 -0.240 2 139 -0.560 146 -0.138 Antonio Senzatela -0.048 -0.504 -0.030 3 142 -0.581 147 -0.139 Ervin Santana -0.460 -0.040 0.345 -0.477 4 146 -0.632 148 -0.142 Kyle Kendrick -0.313 1 128 -0.313 149 -0.148 German Marquez -0.294 0.335 -0.631 3 143 -0.590 150 -0.150

Noteworthy Arsenals

Alex Wood – at some point I need to stop being surprised by Alex Wood. Since the start of last season, he’s thrown 141 innings with a 2.55 ERA, 2.53 FIP, and 2.88 xFIP on the back of funky deception and three above average pitches. This season, Wood features the league’s 3rd best sinker, 17th best curve, and 25th best changeup.

Always one to generate ground balls, he’s now doing so at a near league-leading clip. And the whiffs? Well, he’s first on the Dodgers in strikeout rate, which should tell you all you need to know. And going back one year, Wood’s K-BB% ranks 10th in the league among starters who’ve thrown as many innings. As long as he stays healthy, Alex Wood is as good as any.

Robbie Ray – I have to admit, I’m still not aboard the Robbie Ray Train. I’ve never been able to get past his command and homer problems. But to be fair, neither has he. Ray is walking more batters and inducing fewer ground balls than ever before. And there doesn’t there seem to be an easy fix tinkering with his pitch mix either. His two most underthrown pitches are his four-seamer, which is merely average at generating grounders, and his curveball which he actually throws fairly often; it’s considered underthrown not because he throws it less frequently than the average pitcher does but because it’s so effective, he should throw it as often as possible.

Perhaps Ray has found a way to manage elevated contact but with an average Fly Ball and Line Drive Exit Velocity in the 75th percentile (in this case, high is bad), I’m not too eager to wait around to find out. Ray’s elite arsenal score is supported almost entirely by incredible swing-and-miss and stuff, which undeniably has value. And perhaps, in this inflated offensive environment, you can stomach an ERA more in line with his FIP or xFIP. Just don’t be surprised to see a sharp ERA correction in the second half. Ray should net a haul in return. Those with pitching to spare, and I realize there are just a handful of you, might consider selling high.

Lance Lynn – despite his placement on this list, I’d caution against buying Lynn. His fastball and sinker velocity dropped precipitously a few starts ago starts and though it returned in his last outing, he’s the unlucky protagonist in a long and storied injury history. So while those two games may prove nothing more than a blip, I’m still concerned enough to wait and see.

Jimmy Nelson – if you haven’t already, I’d suggest listening to this latest episode of The Sleeper and the Bust. Paul and Eno do a great job of analyzing changes to Nelson’s breaking pitches that explain his unforeseen success (sincere apologies to anyone who foresaw said success but I know you’re lying so, I forgive you). After being inexplicably cut in one of my Ottoneu leagues a few weeks ago, I’ve been riding him ever since. Nelson’s post-hype breakout has been one of the truly rewarding stories in this pitching-starved environment.

Clayton Kershaw – a commenter last week pointed out that Kershaw was too low on this list. How could I argue otherwise? I mean, I tried but I admit I felt silly doing so. This is one of the limitations with any purely quantitative framework – some results just don’t pass the smell test. That doesn’t mean your whole model sucks, just that you need to buttress your numbers with some common sense. But as I pointed out in my response, as good as Kershaw has been, he hasn’t been the same Kershaw to which we’ve grown accustomed. This isn’t a knock nor is it to say he won’t “turn things around.” And yes, I recognize how ridiculous I sound, hence the “air” quotes that actually aren’t “air” quotes because they appear on the screen in front of you.

But we’re looking at Kershaw’s lowest strikeout rate, K-BB%, and whiff rate since 2013 and his lowest ground ball rate since 2011. And the homers are alarming. Hitters are averaging 1.24 bombs per nine innings off Kershaw; not only is that significantly above the league average, it’s nearly 150% higher than his career rate through last season. Check out Jeff Sullivan’s piece on this very issue here.

Now, that doesn’t tell the whole tale. Obviously. When it comes to contact management, Kershaw is on the right side of average for most Statcast metrics and most everything else. Honestly, talking about Kershaw’s arsenal is a waste of time. He’s extraordinary. I single him out for no other reason than to illustrate the limitations of scoring arsenals based on just a handful of outcomes. But since you came here for fantasy advice, here it is: for anyone playing in the 1% of Yahoo! leagues where Clayton Kershaw is available, consider picking him up. I’d even burn a high waiver priority to do so.

Most Underowned Arsenal

Trevor Cahill is groin-grabbingly underowned. I’ve mentioned him here for his slider and again here for his entire arsenal. In his first start back from a shoulder injury, Cahill tossed 4.1 shutout innings, striking out four and inducing grounders on 82% of the balls Cleveland hitters put in play. Vintage 2017 Cahill. No, he didn’t dominate but he was likely on a strict pitch count and facing one of the league’s hottest lineups. Still available in 78% of Yahoo! leagues, PICK HIM UP.

On another note, this is my last article at RotoGraphs, at least for a while. I’m moving onto other things and as much as I love writing here, I can no longer put in the requisite time to churn out pieces capable of satiating the voracious analytic appetites of this site’s devoted and discerning readership. It’s been a blast and a truly cromulent honor to contribute to my favorite website for the past two years. Hopefully, I get to do so again soon. Thanks for the positive comments and for keeping me honest when I deserved it.