wPDI for Starting Pitchers: Mid-August Update

Earlier this season, I introduced a new pitcher metric – Weighted Plate Discipline Index (wPDI). It is a way to aggregate the six possible plate discipline outcomes into one simple quantity. By using plate discipline data alone, wPDI highlights the percentage of deceptive/effective pitches thrown.

Some lesser known undervalued pitchers who were revealed by wPDI in 2018 included Domingo German, Marco Gonzales, Will Smith and Ryan Pressly. Of course, wPDI also confirmed stars such as Chris Sale, Jacob deGrom, Max Scherzer and Aroldis Chapman.

You can find the definitions and indexes of wPDI in its introductory article, found here.

Here is a quick reminder on what the six possible plate discipline outcomes look like:

Classifying the 6 Pitching Outcomes
Outcome Outcome Outcome Outcome Outcome Outcome
Zone? Out of Zone Out of Zone Out of Zone In Zone In Zone In Zone
Swing? Swung On Swung On No Swing Swung On Swung On No Swing
Contact? No Contact Contact Made No Swing No Contact Contact Made No Swing

Let’s take a look at the 2019 year to date wPDI leaderboard, for starting pitchers [minimum 25 IP]:

Starting Pitcher 2019 wPDI Leaderboard
Name IP wPDI
Blake Snell 101.0 .383
Chris Sale 140.7 .379
Mike Clevinger 62.7 .378
Justin Verlander 157.7 .371
Stephen Strasburg 152.3 .369
Zac Gallen 41.3 .366
Gerrit Cole 156.7 .363
Brendan McKay 29.7 .362
Max Scherzer 134.3 .360
Luis Castillo 137.0 .360
Kenta Maeda 122.3 .358
Shane Bieber 156.3 .357
Patrick Corbin 147.7 .356
Charlie Morton 149.0 .355
Jacob deGrom 143.0 .354
Domingo German 109.0 .353
Felix Hernandez 38.7 .353
Robbie Ray 140.0 .353
Matthew Boyd 140.7 .353
Dinelson Lamet 30.0 .352
Matt Shoemaker 28.7 .352
Aaron Nola 147.3 .351
Tommy Milone 74.7 .350
Lucas Giolito 130.7 .350
Yu Darvish 132.0 .348
Jose Berrios 147.3 .348
Felix Pena 96.3 .348
Jameson Taillon 37.3 .347
Chris Archer 113.7 .347
Kyle Gibson 127.3 .347
Hyun-Jin Ryu 135.7 .346
Kevin Gausman 82.0 .345
Sam Gaviglio 74.3 .345
Kyle Hendricks 129.3 .345
Dylan Bundy 114.3 .345
Griffin Canning 79.3 .344
Caleb Smith 106.7 .344
Corey Kluber 35.7 .344
Zack Greinke 152.0 .344
Frankie Montas 90.0 .341
Gio Gonzalez 50.7 .341
Joshua James 51.3 .340
Francisco Liriano 54.3 .340
Walker Buehler 137.3 .340
Carlos Carrasco 65.0 .340
James Paxton 102.3 .340
Andrew Heaney 49.7 .339
Jack Flaherty 128.3 .338
Alex Young 38.0 .338
Eduardo Rodriguez 140.3 .337
Mike Minor 147.0 .337
Rich Hill 53.0 .336
German Marquez 155.0 .336
Ross Stripling 76.7 .336
Sonny Gray 127.7 .335
Trevor Bauer 168.3 .335
Jake Odorizzi 120.3 .334
Cole Hamels 107.7 .334
Noah Syndergaard 148.0 .333
Jordan Zimmermann 72.0 .333
Anibal Sanchez 112.7 .332
Miles Mikolas 132.3 .332
Chris Paddack 110.3 .332
Minimum 25 IP

Blake Snell sits atop the starting pitcher wPDI leaderboard [min 25 IP] at .383. Sale was already the 7th highest wPDI starting pitcher last season at .361. He has risen to even higher heights in 2019 before his injury.

Other notable recognizable names in the top ten include Chris Sale, Justin Verlander, Stephen Strasburg, Gerrit Cole, Mike Clevinger and Max Scherzer.

Mike Clevinger (.378 wPDI) makes this list at #3 mostly due to his high Outcome D & F components. He generates little contact within the zone; his pitches are either swung on and missed, or not swung on at all. In addition, his component E is the lowest for any starter in baseball (a good thing!). Clevinger is unbelievably effective within the zone.

A few other 2018 wPDI standouts still continue to shine in 2019. Luis Castillo, Patrick Corbin and Charlie Morton have rated highly now for two years in a row. Shane Bieber, Kenta Maeda and Domingo German have now further cemented their prominence in wPDI.

Here are the key individual plate discipline outcome performers for 2019:

  • Outcome A – Blake Snell, Luis Castillo, Kyle Gibson
  • Outcome B – Tommy Milone, Kevin Gausman, Hyun-Jin Ryu, Jacob deGrom
  • Outcome C – Brendan McKay, Justin Verlander, Jameson Taillon
  • Outcome D – Mike Clevinger, Justin Verlander, Lucas Giolito, Jacob deGrom
  • Outcome E – Mike Clevenger Luis Castillo, Robbie Ray
  • Outcome F – Felix Hernandez, Chris Sale, Aaron Nola

A few rookie performers to catch my eye this year include Brendan McKay and Zac Gallen.

Brendan McKay (.362 wPDI) has the lowest Outcome C of all starting pitchers. That is, as a percentage of pitches thrown, he throws the fewest would-be called balls. A large percentage of his overall pitches are thrown within the zone (44% Zone%). His ERA is currently at 4.55, but wPDI thinks he may be a tad unlucky. Some other ERA estimators concur including SIERA, which has him almost a full run lower at 3.66. Keep your eye on this Tampa rookie.

Zac Gallen (.366 wPDI), who was just traded to the Diamondbacks for prospect Jazz Chisholm is another rookie wPDI standout. He is currently enjoying a fantastic first taste of the big leagues. To date, he has pitched to a 2.40 ERA with a 1.14 WHIP. He has fanned 49 batters in just over 41 innings – a K/9 of 11. Gallen doesn’t excel at any one plate discipline outcome – he has a nice base in all 6 outcomes. Unlike McKay whose true talent might be better than his performance thus far – Gallen’s wPDI serves to confirm his exemplary rookie season.

One other notable pitcher is Dinelson Lamet (.352 wPDI). Lamet, who very recently came back from Tommy John surgery, has now thrown 30 innings this season for an ERA of 3.90 ERA. He has amassed 42 strikeouts in that span for a fantastic K/9 of 13. In terms of plate discipline outcomes, Lamet sports a deception profile. He excels at throwing pitches out of the zone for whiffs, while also not generating swings at pitches inside the zone. If you recall – prior to his injury, he was a flashy rookie thought of to have high upside. The best might yet to come for Lamet. He may be an undervalued asset heading into 2020.

We hoped you liked reading wPDI for Starting Pitchers: Mid-August Update by Ariel Cohen!

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Ariel is the 2019 FSWA Baseball Writer of the Year. He is the creator of the ATC (Average Total Cost) Projection System. Ariel was ranked by FantasyPros as the #1 fantasy baseball expert in 2019. His ATC Projections were ranked as the #1 most accurate projection system in 2019. Ariel also writes for CBS Sports, SportsLine, RotoBaller, and is the host of the Great Fantasy Baseball Invitational - Beat the Shift Podcast (@TGFBI). Ariel is a member of the inaugural Tout Wars Draft & Hold league, a member of the inaugural Mixed LABR Auction league and plays high stakes contests in the NFBC. Ariel Cohen is a fellow of the Casualty Actuarial Society (CAS) and the Society of Actuaries (SOA). He is a Vice President of Risk Management for a large international insurance and reinsurance company. Follow Ariel on Twitter at @ATCNY.

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I wouldn’t have clicked if I knew what wPDI was beforehand. I assumed it was Wander Punishment Done Indicator and was going to measure the amount of damage generational prospect Wander Javier would do to these pitchers. Sadly it is not. So I’m out.