Tagged: David Price

Predicting pitchers’ strikeouts using xK%

Expected strikeout rate, or what I will henceforth refer to as “xK%,” is exactly what it sounds like. I want to see if a pitcher’s strikeout rate actually reflects how he has pitched in terms of how often he’s in the zone, how often he causes batters to swing and miss, and so on. Ideally, it will help explain random fluctuations in a pitcher’s strikeout rate, because even strikeouts have some luck built into them, too.

An xK% metric is not a revolutionary idea. Mike Podhorzer over at FanGraphs created one last year, but he catered it to hitters. Still, it’s nothing too wild and crazy like WAR or SIERA or any other wacky acronym. (A wackronym, if you will.)

Courtesy of Baseball Reference, I constructed a set of pitching data spanning 2010 through 2014. I focused primarily on what I thought would correlate highly with strikeout rates: looking strikes, swinging strikes and foul-ball strikes, all as a percentage of total strikes thrown. I didn’t want the model specification to be too close to a definition, so it’s beneficial that these rates are on a per-strike, rather than per-pitch, basis.

The graph plots actual strikeout rates versus expected strikeout rates with the line of best fit running through it. I ran my regression using the specification above and produced the following equation:

xK% = -.6284293 + 1.195018*lookstr + 1.517088*swingstr + .9505775*foulstr
R-squared = .9026

The R-squared term can, for easy of understanding, be interpreted as how well the model fits the data, from 0 to 1. An R-squared, then, of .9026 represents approximately a 90-percent fit. In other words, these three variables are able to explain 90 percent of a strikeout rate. (The remaining 10 percent is, for now, a mystery!)

In order for the reader to use this equation to his or her own benefit, one would insert a pitcher’s looking strike, swinging strike and foul-ball strike percentages into the appropriate variables. Fortunately, I already took the initiative. I applied the results to the same data I used: all individual qualified seasons by starting pitchers from 2010 through 2014.

The results have interesting implications. Firstly, one can see how lucky or unlucky a pitcher was in a particular season. Secondly, and perhaps most importantly, one can easily identify which pitchers habitually over- and under-perform relative to their xK%. Lastly, you can see how each pitcher is trending over time. Every pitcher is different; although the formula will fit most ordinary pitchers, it goes without saying that the aces of your fantasy squad are far from ordinary, and they should be treated on an individual basis.

(Keep in mind that a lot of these players only have one or two years’ worth of data (as indicated by “# Years”), so the average difference between their xK% and K% as a representation of a pitcher’s true skill will be largely unreliable.)

It is immediately evident: the game’s best pitchers outperform their xK% by the largest margins. Cliff Lee, Stephen Strasburg, Clayton Kershaw, Felix Hernandez and Adam Wainwright are all top-10 (or at least top-15) fantasy starters. But let’s look at their numbers over the years, along with a few others at the top of the list.

Kershaw and King Felix have not only been consistent but also look like like they’re getting better with age. Wainwright’s difference between 2013 and 2014 is a bit of a concern; he’s getting older, and this could be a concrete indicator that perhaps the decline has officially begun. Darvish’s line is interesting, too: you may or may not remember that he had a massive spike in strikeouts in 2013 compared to his already-elite strikeout rate the prior year. As you can see, it was totally legit, at least according to xK%. But for some reason, even xK% can fluctuate wildly from year to year. I see it in the data, anecdotally: Anibal Sanchez‘s huge 6.7-percent spike in xK% from 2012 to 2013 was followed by a 5.5-percent drop from 2013 to 2014. Conversely, David Price‘s 5-percent decrease in xK% from 2012 to 2013 was followed by an almost perfectly-equal 5-percent increase from 2013 to 2014. So the phenomenon seems to work both ways. Thus, perhaps it shouldn’t have come as a surprise when Darvish couldn’t repeat his 2013 success. To the baseball world’s collective dismay, we simply didn’t have enough data yet to determine which Yu was the true Yu. I plan to do some research to see how often these severe spikes in xK% are mere aberrations versus how often they are sustained over time, indicating a legitimate skills improvement.

I have also done my best to compile a list of players with only one or two years’ worth of data who saw sizable spikes and drops in their K% minus xK% (“diff%”). The idea is to find players for whom we can’t really tell how much better (or worse) their actual K% is compared to their xK% because of conflicting data points. For example, will Corey Kluber be a guy who massively outperforms his xK% as he did in 2014, or does he only slightly outperform as he did in 2013? I present the list not to provide an answer but to posit: Which version of each of these players is more truthful? I guess we will know sometime in October.

Name: [2013 diff%, 2014 diff%]

And here some fantasy-relevant guys with only data from 2014:

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Bold prediction #3: Corey Kluber is this year’s Hisashi Iwakuma

Bold Prediction #2: Brad Miller will be a top-5 shortstop
Bold Prediction #1: Tyson Ross will be a top-45 starter (until he reaches his innings cap)

The Corey Kluber Society, fronted by Carson Cistulli of FanGraphs, is, frankly, hilarious. The format of the post is great, and if you haven’t read it before, you should here.

But there’s a more important reason to read about (and “join”) the Society. Kluber is not only a legitimate fantasy starting pitcher but also a very good one. His breakout last year was muted by a couple of bad starts, but he is a perfect comp to a 2012 Hisashi Iwakuma on the verge.

I will list a variety of statistics in which Kluber excelled. Then I will let you know whom he outperformed in each category for all pitchers with at least 140 innings pitched (1o7 total).

K/9: 8.31 (26th overall)
Better than: Cole Hamels, Julio Teheran, Adam Wainwright, Mat Latos, Mike Minor

K/BB: 4.12 (11th overall)
Better than: Hamels, Jordan Zimmermann, Teheran, Anibal Sanchez, Homer Bailey

BAbip: .329 (6th worst)

Swinging strike rate: 10.4% (22nd overall)
Better than: Zack Greinke, Latos, Iwakuma, Scott Kazmir, Jose Fernandez

Contact rate: 76.8% (16th overall)
Better than: Kris Medlen, Jeff Samardzija, Bailey, Greinke, Fernandez

xFIP-: 78 (11th overall)
Better than: Max Scherzer, Fernandez, David Price, Iwakuma, Stephen Strasburg

Yowza. Those are some seriously stellar numbers. What’s the deal? Unfortunately for Kluber, he suffered a brutal outing or two, causing his WHIP and ERA to be inflated for most of the year and allowing him to fly under the radar. Chalk it up to bad luck, considering Kluber’s 6th-worst BAbip, better than only Joe Saunders, Dallas Keuchel and other names one wishes not to be associated with.

This sounds vaguely familiar. A high-control guy with a solid strikeout rate out of the bullpen? Does the name Hisashi Iwakuma ring a bell? It should, because he has already been mentioned several times in the last 300 words. Anyway, I rode the Iwakuma (and Bailey) wave through the end of 2012. Instead of going with my gut and drafting Iwakuma in the last round of my shallow draft in 2013, I opted for Marco Estrada — not a terrible pick, but clearly not the right gamble to take. It’s actually the moment upon which I reflected and realized that I should really just take my own advice. Because given Dan Haren‘s peripherals, why would anyone have trusted him over Bailey last year? Ridiculous. (FYI, I will rip on Haren in a forthcoming bold prediction, just to be clear that I’m not ripping on him because he gave up a million home runs last year.)

But I digress. Iwakuma was good in 2012, but his 7.25 K/9, 2.35 K/BB and 1.28 WHIP were all rather pedestrian. But sometimes you need to rely on your eyes more than the numbers, and anyone who watched Iwakuma saw flashes of brilliance. 2013 may have been more than we anticipated, which brings me to my point:

Kluber already has the makings of a great pitcher, and his peripherals indicate that none of it was a fluke. My official prediction: Corey Kluber will be a top-40 starting pitcher.

The role of luck in fantasy baseball

I apologize for being that guy that ruins that ooey gooey feeling you get when think about the fantasy league you won last year. As much as you want to think you are a fantasy master — perhaps even a fantasy god — you should acknowledge that you probably benefited from a good deal of luck. Sure, for your sake, I will admit you made a great pick with Max Scherzer in the fifth round. But did you, in all your mastery, predict he would win 21 games?

Don’t say yes. You didn’t. And frankly, you would be crazy to say he’ll do it again.

I focus primarily on pitching in this blog, and let it be known that pitchers are not exempt from luck in the realm of fantasy baseball. If you’re playing in a standard rotisserie league, you probably have a wins category. In a points league, you likely award points for wins.

Wins. Arguably the most arbitrary statistic in baseball. Let’s not have that discussion, though, and instead simply accept the win as it is. The win has the most drastic uncontrollable effect on a fantasy pitcher’s value. (ERA and WHIP experiences similar statistical fluctuations, but at least they aren’t arbitrary.)

I had an idea, but before I proceed, let me interject: if you’re drafting for wins, you’re doing it wrong. But, as I said, you can’t ignore wins.

But let’s say you did, and drafted strictly on talent, or “stuff” (which, here, factors in a pitcher’s durability). How would the top 30 pitchers change? Here’s my “stuff” list, which you can compare with the base projections:

  1. Clayton Kershaw
  2. Adam Wainwright
  3. Felix Hernandez
  4. Max Scherzer
  5. Cliff Lee
  6. Yu Darvish
  7. Chris Sale
  8. Cole Hamels
  9. Jose Fernandez
  10. Madison Bumgarner
  11. Stephen Strasburg
  12. David Price
  13. Justin Verlander
  14. Alex Cobb
  15. Homer Bailey
  16. Mat Latos
  17. Gerrit Cole
  18. Michael Wacha
  19. Anibal Sanchez
  20. James Shields
  21. Danny Salazar
  22. Marco Estrada
  23. A.J. Burnett
  24. Corey Kluber
  25. Brandon Beachy
  26. Zack Greinke
  27. Matt Cain
  28. Sonny Gray
  29. Hisashi Iwakuma
  30. Gio Gonzalez

Here are the five players with the biggest positive change and a breakdown of each:

  1. Brandon Beachy, up 23 spots
    His injury history has weakened his wins column projection. Consequently, the number of innings Beachy is expected to throw is significantly less than a full season. But if he managed to stay healthy for the full year (say, 200 innings)? He’s a top-1o pick based on pure stuff. If you draft with the philosophy that you can always find a viable replacement on waivers, Beachy could be your big sleeper.
  2. Marco Estrada, up 22 spots
    Estrada’s diminished expected wins is more a function of his terrible team than ability. Estrada has underperformed the past two years, Ricky Nolasco style, but if he can pull it together, he’s a top-30 pitcher based on “stuff.” And hey, maybe he can luck into some extra wins. However, if he can’t pull it together — Ricky Nolasco style — he’ll be relegated to fringe starter.
  3. Danny Salazar, up 9 spots
    Salazar has immense potential. His injury history led the Indians to cap his per-game pitch count last year, and that has been factored into his projection. But if he’s a full-time, 200-inning starter? He’s a top-25 starter with top-15 upside. Again, this is in terms of “stuff”. But is Ivan Nova better than Felix Hernandez because he can magically win more games? Of course not. Among a slew of young studs, including Jose Fernandez, Shelby Miller, Michael Wacha and so on, Salazar is a diamond in the rough.
  4. A.J. Burnett, up 8 spots
    His projection is already plenty good. But you saw how many games he won in 2013. Anything can happen.
  5. Corey Kluber, up 8 spots
    Most people were probably scratching their heads when they saw Kluber’s name listed above. Frankly, I’m in love with him, and it’s because he’s a stud with a great K/BB ratio. I understand why someone may be inclined to dismiss it as an aberration, but his swinging strike and contact rates are truly excellent. Even if they regress, he should be a draft-day target.

Here are the three starting pitchers with the biggest negative change.

  1. Anibal Sanchez, down 10 spots
    He’s great, but he also plays for a great team. Call it Max Scherzer syndrome. He carries as big a risk as any other player to pitch great but only win five or six games, as do the next two players.
  2. Hisashi Iwakuma, down 6 spots
  3. Zack Greinke, down 4 spots

Let me be clear that although I created a hypothetical scenario where wins didn’t exist, I don’t advocate for blindly drafting based on “stuff.” It’s important to acknowledge that certain players have a much better chance to win than others. Chris Sale of the Chicago White Sox could win 17 games just as easily as he could win seven. It’s about playing the odds — and unless a pitcher truly pitches terribly, don’t blame the so-called experts for your bad luck. He probably put his money where his mouth is, too, and is suffering along with you.

Here is a more comprehensive list of pitchers ranked by “stuff,” if that’s the way you sculpt your strategy:

  1. Clayton Kershaw
  2. Adam Wainwright
  3. Felix Hernandez
  4. Max Scherzer
  5. Cliff Lee
  6. Yu Darvish
  7. Chris Sale
  8. Cole Hamels
  9. Jose Fernandez
  10. Madison Bumgarner
  11. Stephen Strasburg
  12. David Price
  13. Justin Verlander
  14. Alex Cobb
  15. Homer Bailey
  16. Mat Latos
  17. Gerrit Cole
  18. Michael Wacha
  19. Anibal Sanchez
  20. James Shields
  21. Danny Salazar
  22. Marco Estrada
  23. A.J. Burnett
  24. Corey Kluber
  25. Brandon Beachy
  26. Zack Greinke
  27. Matt Cain
  28. Sonny Gray
  29. Hisashi Iwakuma
  30. Gio Gonzalez
  31. Doug Fister
  32. Jordan Zimmermann
  33. Alex Wood
  34. Kris Medlen
  35. Jeff Samardzija
  36. Mike Minor
  37. Jake Peavy
  38. Kevin Gausman
  39. Tyson Ross
  40. Patrick Corbin
  41. Lance Lynn
  42. Francisco Liriano
  43. Andrew Cashner
  44. Ricky Nolasco
  45. CC Sabathia
  46. Hiroki Kuroda
  47. Tim Lincecum
  48. Tim Hudson
  49. Jered Weaver
  50. Shelby Miller
  51. Clay Buchholz
  52. Tony Cingrani
  53. Matt Garza
  54. John Lackey
  55. Ubaldo Jimenez
  56. Justin Masterson
  57. Julio Teheran
  58. R.A. Dickey
  59. A.J. Griffin
  60. Hyun-Jin Ryu
  61. Dan Haren
  62. Johnny Cueto
  63. C.J. Wilson
  64. Ian Kennedy
  65. Chris Archer
  66. Kyle Lohse
  67. Scott Kazmir
  68. Carlos Martinez
  69. Jon Lester
  70. Ervin Santana
  71. Jose Quintana
  72. Derek Holland
  73. Garrett Richards
  74. Dan Straily
  75. Tyler Skaggs

Early SP rankings for 2014

I wouldn’t say pitching is deep, but I’m surprised by the pitchers who didn’t make my top 60.

Note: I have deemed players highlighted in pink undervalued and worthy of re-rank. Do not be alarmed just yet by what you may perceive to be a low ranking.

2014 STARTING PITCHERS

  1. Clayton Kershaw
  2. Adam Wainwright
  3. Max Scherzer
  4. Yu Darvish
  5. Felix Hernandez
  6. Cliff Lee
  7. Stephen Strasburg
  8. Jose Fernandez
  9. Cole Hamels
  10. Justin Verlander
  11. Anibal Sanchez
  12. Chris Sale
  13. Mat Latos
  14. Madison Bumgarner
  15. Alex Cobb
  16. Homer Bailey
  17. Gerrit Cole
  18. Zack Greinke
  19. David Price
  20. James Shields
  21. Jordan Zimmermann
  22. Michael Wacha
  23. Danny Salazar
  24. Jered Weaver
  25. A.J. Burnett *contingent on if he retires
  26. Kris Medlen
  27. Mike Minor
  28. Jake Peavy
  29. Corey Kluber
  30. Lance Lynn
  31. Matt Cain
  32. Hisashi Iwakuma
  33. CC Sabathia
  34. Gio Gonzalez
  35. Doug Fister
  36. Patrick Corbin
  37. Francisco Liriano
  38. Sonny Gray
  39. Ricky Nolasco
  40. Hiroki Kuroda
  41. Tim Hudson
  42. Marco Estrada
  43. Shelby Miller
  44. Trevor Rosenthal
  45. Tony Cingrani
  46. A.J. Griffin
  47. Brandon Beachy
  48. Tim Lincecum
  49. Clay Buchholz
  50. Ubaldo Jimenez
  51. Alex Wood
  52. Julio Teheran
  53. Tyson Ross
  54. Hyun-jin Ryu
  55. Matt Garza
  56. Andrew Cashner
  57. Johnny Cueto
  58. C.J. Wilson
  59. John Lackey
  60. Justin Masterson
  61. R.A. Dickey
  62. Kevin Gausman
  63. Jon Lester
  64. Dan Haren
  65. Ervin Santana
  66. Derek Holland
  67. Chris Archer
  68. Jeff Samardzija
  69. Bartolo Colon
  70. Ivan Nova
  71. Matt Moore
  72. Ian Kennedy
  73. Dan Straily
  74. Rick Porcello
  75. Jarrod Parker
  76. Carlos Martinez
  77. Jeremy Hellickson
  78. Kyle Lohse
  79. Scott Kazmir
  80. Jason Vargas
  81. Tommy Milone
  82. Wade Miley
  83. Dillon Gee
  84. Brandon Workman
  85. Chris Tillman
  86. Zack Wheeler
  87. Yovani Gallardo
  88. Miguel Gonzalez
  89. Jose Quintana
  90. Garrett Richards
  91. Robbie Erlin
  92. Felix Doubront
  93. Jhoulys Chacin
  94. Jonathon Niese
  95. Chris Capuano
  96. Nick Tepesch
  97. Alexi Ogando
  98. Bronson Arroyo
  99. Travis Wood
  100. Trevor Cahill
  101. Tyler Skaggs
  102. Randall Delgado
  103. Martin Perez
  104. Mike Leake
  105. Carlos Villanueva
  106. Todd Redmond
  107. Brandon Maurer
  108. Tyler Lyons
  109. Ryan Vogelsong
  110. Zach McAllister
  111. Wily Peralta
  112. Brett Oberholtzer
  113. Erik Johnson
  114. Jorge De La Rosa
  115. Paul Maholm
  116. Hector Santiago
  117. Burch Smith
  118. Jeff Locke
  119. Joe Kelly
  120. Jason Hammel
  121. Jake Odorizzi
  122. Danny Hultzen
  123. Anthony Ranaudo
  124. Archie Bradley
  125. Rafael Montero
  126. James Paxton
  127. Taijuan Walker
  128. Yordano Ventura