How Accurately Can We Predict a Hitter’s Strikeout and Walk Rates?

Plate discipline is a crucial skill for every single major league player. Being able to lay off of bad pitches, make contact, and control the strike zone are skills that provide the foundation for some of the game’s best players to be great. These skills manifest themselves through important stats like strikeout and walk rate. If we could predict, with a reasonable degree of accuracy, how often a hitter walks or strikes out as the product of skill-based rates, we would open another window into player talent.

This article is my first attempt at mathematical analysis, and I would appreciate constructive criticism in the comments. Data used includes seasons with the minimum number of PA for the modeled statistic to stabilize (Reference: Rate at which K% and BB% stabilize) from 2002-2014 from all non-pitchers. With the size of this data, the possibility of overfitting is reduced. All statistics are through June 18, 2015.

Before we begin, I would like to briefly explain terminology: O-Swing% is the rate at which hitters swing at pitches outside of the strike zone as defined by Pitch-F/X; SwStr% is the rate at which hitters swing and miss; F-Strike% is the percentage of first strikes a hitter sees in his at bats.

To begin, I looked at expected strikeout rate. My model uses main effects for O-Swing%, SwStr%, and F-Strike%, as well as interaction effects between SwStr% and F-Strike%, O-Swing% and F-Strike%, and O-Swing% and SwStr%.

At first glance, the chart seems to produce a fairly reasonable result; if you don’t swing at bad pitches and make contact, you’re less likely to strike out.

Next up, we can tackle BB%. To define terminology once again: Z-Contact% is the rate at which a hitter makes contact on pitches inside the strike zone; Swing% is the rate at which a hitter swings at pitches.

My model uses main effects for Z-Contact%, Swing%, and F-Strike%, as well as interaction effects between Swing% and F-Strike%, Z-Contact% and Swing%, and Z-Contact% and F-Strike%.  As a fair warning, the data may be unreliable as of right now; walk rate takes 120 PA to stabilize, and not all hitters in the sample have reached that yet.

Again, fairly reasonable. If you can control the strike zone by fighting off pitches and being disciplined with when you swing, you’ll walk more.

This data has shown that in the past, players who excel in these plate discipline statistics boast better walk and strikeout rates. If this information proves to be predicted, we can believe that players with xK% higher than their actual K% are likely to strike out more, and vice versa based on these underlying statistics remaining similar, and players with xBB% higher than their actual BB% can expect to walk more, with the opposite being true as well. Here is my full set of data:

Name
xK%
K%
∆K%
xBB%
BB%
∆BB%
Ben Zobrist9.938.6-1.3314.4911.4-3.09
Nick Markakis9.3812.53.1211.3212.91.58
Alberto Callaspo10.0710.40.3311.9611.6-0.36
Shane Victorino13.1613.60.4415.4813.6-1.88
Carlos Santana12.4815.63.1214.5619.14.54
Angel Pagan9.5414.65.0610.695-5.69
Michael Brantley8.586.6-1.989.5711.92.33
Brayan Pena9.177.7-1.4710.179.3-0.87
Sandy Leon9.5513.43.8510.27.5-2.7
Brett Gardner13.8519.85.9514.599.3-5.29
Jayson Werth13.39217.6114.0110.1-3.91
Ichiro Suzuki8.3910.31.917.917.7-0.21
Cliff Pennington15.814.4-1.414.6913.3-1.39
Sam Fuld12.0615.63.5411.029.8-1.22
Chase Utley10.9212.71.789.828.9-0.92
Stephen Vogt13.54206.4611.9114.62.69
Ben Revere9.5910.71.118.384.8-3.58
Denard Span9.738.7-1.038.437.3-1.13
Josh Reddick12.449.1-3.3410.039.5-0.53
Logan Forsythe12.9215.82.8810.28.5-1.7
Dustin Ackley12.6518.76.059.897.1-2.79
Brock Holt12.83207.171011.71.7
Eric Sogard10.5913.93.318.245.1-3.14
Anthony Rizzo14.7612.4-2.3611.2612.10.84
Dustin Pedroia12.0112.20.199.158.8-0.35
Matt Carpenter13.9419.75.7610.5712.11.53
Jake Elmore12.714.11.49.515.9-3.61
Jose Ramirez13.0414.11.069.557.6-1.95
Brian McCann13.4818.14.629.866.9-2.96
Curtis Granderson15.4323.47.9711.1912.10.91
Mookie Betts11.3120.78.157.3-0.85
Paul Goldschmidt17.8818.80.9212.7818.55.72
David DeJesus10.3913.83.417.426.6-0.82
Yasmani Grandal14.5818.43.8210.3315.75.37
Jose Bautista16.1816-0.1811.3217.66.28
Roberto Perez19.230.311.113.4184.6
Desmond Jennings13.9612.5-1.469.749.7-0.04
Martin Prado10.5412.21.667.294.4-2.89
Mike Aviles12.4210.6-1.828.57.8-0.7
Jonny Gomes19.3932.413.0113.29.6-3.6
Adam Eaton13.6716.22.539.117.3-1.81
James Loney11.098.5-2.597.346.8-0.54
Joey Votto17.1218.61.4811.313.92.6
Joe Panik12.0411.8-0.247.918.80.89
Nori Aoki9.916.1-3.816.58.21.7
DJ LeMahieu14.2116.32.099.326.8-2.52
Ryan Raburn16.8116.5-0.3110.979.2-1.77
Kurt Suzuki11.7510.6-1.157.617.1-0.51
Mike Trout15.5622.16.5410.07110.93
Joe Mauer13.3116.43.098.588.60.02
Shin-Soo Choo19.8923.83.9112.729.4-3.32
Manny Machado15.39171.619.838.7-1.13
Elvis Andrus12.2214.21.987.758.20.45
J.J. Hardy14.1421.67.468.963-5.96
Jason Kipnis13.413.50.18.489.81.32
Seth Smith20.8423.82.9613.119.4-3.71
Charlie Blackmon14.3118.84.498.966.9-2.06
Russell Martin14.6319.95.279.1410.41.26
Carlos Ruiz11.7113.92.197.28.71.5
Delino Deshields Jr.17.3123.25.8910.5111.91.39
Dilson Herrera17.6623.45.7410.687.8-2.88
J.B. Shuck10.865.5-5.366.528.21.68
Daniel Nava15.421.96.59.199.60.41
Justin Smoak21.1228.47.2812.4211.9-0.52
Geovany Soto21.633311.3712.676.2-6.47
Jose Iglesias9.628.8-0.825.625.90.28
Jason Heyward15.8618.52.649.255.6-3.65
Martin Maldonado19.2625.46.1411.228.5-2.72
A.J. Ellis1416.22.28.112.24.1
Gregory Polanco15.9419.93.969.218.3-0.91
Victor Martinez12.410-2.47.1510.83.65
Ian Kinsler11.2912.61.316.5110.13.59
Michael McKenry19.7825.96.1211.3414.12.76
Stephen Drew13.6817.43.727.838.20.37
Mike Napoli20.9325.34.3711.86120.14
Alexi Amarista13.4215.62.187.589.51.92
Lucas Duda18.0822.24.1210.1711.10.93
Dexter Fowler18.0121.73.6910.110.30.2
Jimmy Rollins17.0816.9-0.189.517.9-1.61
Marcus Semien17.2220.63.389.567.4-2.16
Robinson Chirinos17.35224.659.5910.71.11
Ike Davis12.8813.91.027.19.62.5
Christian Colon13.9313-0.937.689.11.42
Michael Bourn18.521.32.810.169-1.16
Jonathan Lucroy11.6913.72.016.396-0.39
Melky Cabrera11.6111.1-0.516.345.2-1.14
Alex Avila23.7628.44.6412.9317.64.67
Adam Rosales20.4123.12.6911.088.8-2.28
Gordon Beckham12.5813.20.626.88.82
Austin Jackson15.7520.24.458.55.2-3.3
Max Muncy19.2626.26.9410.389.5-0.88
Jace Peterson18.8217.3-1.5210.1210-0.12
Mark Teixeira16.6914.6-2.098.9614.25.24
Jake Lamb18.3915.4-2.999.8612.32.44
Jacoby Ellsbury12.6313.50.876.7611.24.44
Jordy Mercer16.6115.4-1.218.875.1-3.77
David Ortiz18.9115.7-3.2110.111.21.1
Ryan Hanigan9.7717.98.135.2113.48.19
Jonathan Herrera10.838.3-2.535.741.7-4.04
Jason Rogers19.0918.5-0.5910.14.9-5.2
Edwin Encarnacion19.920.80.910.511.20.7
Tuffy Gosewisch15.6316.71.078.225.8-2.42
David Murphy12.59.2-3.36.575.7-0.87
Mark Canha19.2419.80.5610.118-2.11
Brian Dozier17.57191.439.29.90.7
Adam LaRoche20.8229.48.5810.913.42.5
Mike Moustakas12.6311.1-1.536.595.5-1.09
Micah Johnson17.1320.53.378.926-2.92
Kyle Seager14.4813.6-0.887.547.2-0.34
Jake Smolinski20.14265.8610.3815.14.72
Jung-ho Kang20.8420.5-0.3410.748.2-2.54
Bryce Harper19.4419.90.4610.0119.99.89
Cesar Hernandez14.4716.31.837.4313.25.77
Jose Lobaton22.4927.75.2111.5212.30.78
Buster Posey12.949.2-3.746.62103.38
Alex Gordon17.3819.62.228.8711.52.63
Eric Hosmer18.6217.9-0.729.489.90.42
Dan Uggla19.4823.54.029.8912.32.41
Rickie Weeks22.9326.33.3711.599.5-2.09
Kelly Johnson15.4117.11.697.786.3-1.48
Andrelton Simmons10.986.7-4.285.536.30.77
Daniel Murphy10.27.4-2.85.171.9
Jon Jay12.1614.62.446.0570.95
Johnny Giavotella14.814.5-0.37.347.90.56
Chase Headley17.0920.83.718.455.7-2.75
Chris Stewart13.0912.1-0.996.473-3.47
Nick Swisher21.6621.6-0.0610.687.2-3.48
Cameron Maybin16.4619.12.648.059.51.45
Ender Inciarte11.1811.20.025.463-2.46
Devon Travis15.7918.52.717.657.5-0.15
Yonder Alonso15.7412.2-3.547.62113.38
Carlos Peguero29.3841.111.7214.1414.40.26
Adam Lind18.7219.91.189101
Jed Lowrie18.5320.31.778.9216.27.28
Chris Coghlan17.8817.1-0.788.56101.44
Enrique Hernandez21.8720-1.8710.465-5.46
Chris Iannetta22.327.55.210.6512.11.45
Wilmer Flores12.5712.3-0.275.993.4-2.59
Eric Campbell17.9918.40.418.5610.31.74
Yangervis Solarte13.8611.6-2.266.566.90.34
Trevor Plouffe16.6321.64.977.8191.19
Skip Schumaker14.6115.10.496.8511.34.45
Christian Yelich19.9524.14.159.348.5-0.84
Jarrod Saltalamacchia28.9936.57.5113.510.8-2.7
Zack Cozart14.1713.6-0.576.596.5-0.09
Francisco Cervelli16.8119.12.297.819.51.69
Josh Donaldson21.718.2-3.510.067.7-2.36
Rafael Ynoa14.3723.38.936.624.1-2.52
JR Murphy18.2128.310.098.366.7-1.66
Andrew McCutchen19.5414-5.548.9710.31.33
Jordan Pacheco12.9917.94.915.9411.55.56
Ryan Zimmerman15.2317.11.876.967.30.34
Aaron Hill14.5216.21.686.637.81.17
Jay Bruce20.9623.72.749.55144.45
Andrew Susac22.5625.42.8410.2514.13.85
Albert Pujols14.269.9-4.366.466.1-0.36
Gregor Blanco19.9520.80.858.9810.81.82
Shane Robinson12.3214.72.385.546.40.86
Billy Hamilton14.5115.91.396.495.7-0.79
Luis Valbuena19.3221.52.188.528.1-0.42
Steve Pearce19.3722.22.838.527.2-1.32
Joc Pederson26.6128.92.2911.6716.75.03
George Springer26.4926.3-0.1911.6213.51.88
A.J. Pollock15.39171.616.736.3-0.43
Rougned Odor19.0222.73.688.296.4-1.89
Andre Ethier16.8514.4-2.457.3310.12.77
John Mayberry25.2625-0.2610.969.2-1.76
Justin Turner16.4814-2.487.117.30.19
Tyler Moore2022.62.68.616-2.61
Alex Rodriguez24.6121.7-2.9110.49132.51
Rajai Davis12.1116.64.495.148.33.16
Eduardo Nunez15.9114.3-1.616.735.7-1.03
Billy Butler15.7715.6-0.176.667.30.64
Matt Joyce21.7323.21.479.129.40.28
Ruben Tejada17.6716.5-1.177.389.92.52
Justin Ruggiano26.9133.36.3911.2113.62.39
Hanser Alberto11.5711.70.134.813.3-1.51
Clint Robinson16.3213.7-2.626.787.40.62
Jason Castro24.2925.41.1110.048.5-1.54
Ryan Flaherty19.8427.47.568.189.41.22
David Freese18.6521.32.657.675.9-1.77
Logan Morrison17.7415.8-1.947.268.51.24
Neil Walker17.16202.847.025.6-1.42
Ryan Goins14.7318.53.776.025.6-0.42
Evan Longoria19.719.90.28.0610.32.24
Nick Ahmed19.7623.73.948.0610.12.04
David Peralta18.8119.80.997.658.81.15
Jarrod Dyson13.3715.21.835.412.5-2.91
Miguel Montero20.7221.30.588.3814.86.42
Pedro Alvarez20.8623.62.748.4110.41.99
Xander Bogaerts16.7414.4-2.346.665.3-1.36
Kole Calhoun18.2820.21.927.267.2-0.06
Aaron Hicks18.1117.2-0.917.186.1-1.08
Darin Ruf21.7222.50.788.555.4-3.15
Maikel Franco17.2614.1-3.166.784.7-2.08
Mitch Moreland20.5921.20.618.097.1-0.99
Emilio Bonifacio18.9734.815.837.412.9-4.51
Miguel Cabrera17.316.4-0.96.7615.48.64
Hanley Ramirez17.3513.9-3.456.776-0.77
Travis Snider20.6221.50.888.0410.42.36
Derek Norris18.14223.867.076.3-0.77
Caleb Joseph18.422.13.77.159.32.15
Chris Davis26.4732.35.8310.2711.51.23
Jordan Schafer19.8231.111.287.674.1-3.57
Eric Young19.85200.157.667.1-0.56
Kevin Kiermaier17.8617.8-0.066.894.2-2.69
Jose Reyes14.6114.5-0.115.624.8-0.82
Justin Bour23.9521.9-2.059.210.51.3
Colby Rasmus27.9133.55.5910.7110.1-0.61
Giancarlo Stanton27.8630.12.2410.6811.20.52
Will Middlebrooks21.3522.71.358.194.5-3.69
Brad Miller22.7322.3-0.438.7110.21.49
J.T. Realmuto13.1313.40.275.024.1-0.92
Ezequiel Carrera22.0520.9-1.158.415.5-2.91
Khris Davis25.924.3-1.69.8311.21.37
Troy Tulowitzki19.4721.31.837.344.8-2.54
Freddie Freeman22.1122.30.198.339.20.87
Adrian Beltre14.949.5-5.445.624.5-1.12
Prince Fielder15.4911.2-4.295.817.31.49
Carlos Sanchez20.6524.53.857.733.9-3.83
Starlin Castro18.6117.2-1.416.944.1-2.84
Alex Rios17.2118.31.096.362.4-3.96
Freddy Galvis13.7715.31.535.075.10.03
Kolten Wong17.214.4-2.86.316.80.49
Kevin Plawecki19.7325.45.677.235.7-1.53
Travis d'Arnaud16.6614.3-2.366.072.9-3.17
Jedd Gyorko21.1426.75.567.697.6-0.09
Justin Upton24.5925.61.018.9510.51.55
Chris Carter28.0433.35.2610.1914.34.11
Nelson Cruz24.6425.30.668.938.2-0.73
Brandon Belt23.7226.72.988.579.30.73
Matt Holliday19.7617.9-1.867.1215.17.98
Tucker Barnhart17.1123.46.296.167.81.64
Dee Gordon13.4315.31.874.833.5-1.33
Steven Souza22.3933.711.318.04123.96
Preston Tucker22.6120.7-1.918.0890.92
Carlos Beltran17.2418.71.466.135.1-1.03
Will Venable20.8254.27.377.60.23
Todd Cunningham13.7418.24.464.855.20.35
Wil Myers20.1719.5-0.677.076.3-0.77
Hank Conger18.6827.18.426.5314.17.57
Dalton Pompey27.9224.2-3.729.766.6-3.16
Blake Swihart18.0426.98.866.35.9-0.4
Marcell Ozuna2120-17.297.2-0.09
Everth Cabrera20.51210.497.124.8-2.32
Jose Altuve11.769.8-1.964.075.81.73
Junior Lake28.5632.33.749.856.5-3.35
Carlos Perez19.4820.71.226.692.3-4.39
Matt Duffy16.95181.055.815.2-0.61
David Ross27.0231.44.389.2614.35.04
Alejandro De Aza20.1928.17.916.915.8-1.11
Yasiel Puig20.6717.2-3.477.069.72.64
Elian Herrera17.5323.15.575.956.50.55
Cody Asche20.0524.74.656.715.1-1.61
Daniel Descalso17.6722.54.835.96.70.8
Gerardo Parra16.71192.295.554.9-0.65
Leonys Martin19.6418-1.646.515-1.51
Todd Frazier20.5818.2-2.386.817.91.09
Yoenis Cespedes19.8121.61.796.555.2-1.35
Robinson Cano16.717.20.55.55.1-0.4
Kris Bryant26.4729.32.838.713.44.7
Jonathan Villar20.6125.75.096.777.60.83
Howie Kendrick18.7618.1-0.666.157.31.15
Kristopher Negron20.49210.516.698.61.91
Collin Cowgill24.7624.2-0.568.086.1-1.98
Jean Segura14.6715.71.034.782.9-1.88
Adrian Gonzalez17.4715.4-2.075.6710.34.63
Eduardo Escobar19.7423.84.066.342.8-3.54
Adeiny Hechavarria15.8915.8-0.095.14.5-0.6
Mark Reynolds25.329.64.38.089.51.42
Odubel Herrera19.5625.76.146.214.1-2.11
C.J. Cron16.6520.23.555.251.8-3.45
Kirk Nieuwenhuis28.5140.612.098.976.3-2.67
Hunter Pence25.8718.4-7.478.136.6-1.53
Ryan Braun17.11213.895.379.13.73
Asdrubal Cabrera21.1231.96.626.70.08
Kennys Vargas23.6429.65.967.45.2-2.2
Lorenzo Cain16.73181.275.236.10.87
Rusney Castillo18.6519.20.555.84.1-1.7
Nick Franklin28.3727.5-0.878.838.7-0.13
Carlos Gonzalez24.819.3-5.57.7191.29
Casey McGehee21.1220.6-0.526.547.61.06
Nick Hundley21.36231.646.565.9-0.66
Jorge Soler26.6832.25.528.197.2-0.99
Didi Gregorius19.1416.8-2.345.875.8-0.07
Erick Aybar14.2214.2-0.024.335.20.87
Yadier Molina16.1212.8-3.324.96.81.9
Brandon Moss24.2226.92.687.369.92.54
Scott Van Slyke23.2721-2.277.016-1.01
Brandon Guyer19.7816.6-3.185.945.5-0.44
Omar Infante17.3415.3-2.045.21.4-3.8
Cory Spangenberg17.9922.24.215.387.21.82
Juan Lagares17.9119.41.495.353.9-1.45
Conor Gillaspie19.0219.60.585.674.3-1.37
Brett Lawrie23.1326.93.776.854-2.85
Kevin Pillar16.815.7-1.14.944.6-0.34
Jake Marisnick21.0825.54.426.164.6-1.56
Lonnie Chisenhall14.9616.91.944.373.7-0.67
Tim Beckham26.4229.53.087.76.7-1
Yunel Escobar15.7213.8-1.924.576.72.13
Juan Uribe19.9614.5-5.465.797.31.51
Matt Kemp23.7923.4-0.396.884.6-2.28
Garrett Jones25.5827.92.327.397-0.39
Jose Abreu22.5718.6-3.976.515.5-1.01
Matt Adams19.0522.93.855.485.2-0.28
Addison Russell23.7831.47.626.836.90.07
Alexei Ramirez17.1513.3-3.854.92.8-2.1
Jhonny Peralta20.4918.4-2.095.858.62.75
Kendrys Morales20.715.3-5.45.917.61.69
Alcides Escobar15.5610.4-5.164.442.9-1.54
Torii Hunter19.4216.3-3.125.517.72.19
Billy Burns15.0815.60.524.215.20.99
Michael Cuddyer21.8723.31.436.086.50.42
Michael Taylor26.6832.15.427.397.70.31
Welington Castillo22.9723.80.836.336.70.37
Yan Gomes18.3326.17.775.032.2-2.83
Chris Taylor23.1127.94.796.347.41.06
Chris Young21.7223.11.385.945.6-0.34
David Lough18.5921.63.015.071.4-3.67
Mike Zunino29.1836.27.027.946.5-1.44
Cameron Rupp21.3427.56.165.8104.2
Grady Sizemore19.6522.12.455.335.80.47
Anthony Gose21.1526.25.055.735.6-0.13
Chris Johnson26.8927.80.917.217.60.39
A.J. Pierzynski16.6810.2-6.484.455.40.95
Salvador Perez18.2413.7-4.544.761.8-2.96
Peter Bourjos19.5720.20.635.0810.15.02
Brandon Crawford23.920-3.96.27.10.9
Willie Bloomquist19.3920.30.915.021.6-3.42
Mark Trumbo24.6523.1-1.556.364.4-1.96
Danny Espinosa21.0421.50.465.4104.6
Aramis Ramirez17.1715.8-1.374.44-0.4
Carlos Corporan24.4634.39.846.234.9-1.33
Chris Colabello22.91252.095.75.5-0.2
Josh Harrison18.0914.4-3.694.493.9-0.59
Justin Morneau17.19.6-7.54.232.9-1.33
Jeff Francoeur16.87170.134.174.60.43
Paulo Orlando19.9417.1-2.844.913.4-1.51
Marwin Gonzalez20.622.31.75.032-3.03
James McCann22.1522.1-0.055.354.3-1.05
Kyle Blanks22.8228.25.385.55.60.1
Josh Phegley18.1412.2-5.944.326.72.38
Brandon Phillips16.7112.1-4.613.925.21.28
Ian Desmond20.6628.17.444.854.7-0.15
Tyler Flowers22.5133.110.595.224.2-1.02
Justin Maxwell27.0823.7-3.386.225.8-0.42
Luis Sardinas17.8819.71.824.092.8-1.29
Wilson Ramos20.8416-4.844.753.4-1.35
Pablo Sandoval17.5814.2-3.383.995.21.21
Danny Valencia19.8321.21.374.394-0.39
Brandon Barnes22.8522.7-0.154.934.5-0.43
Corey Dickerson22.9924.11.114.944.5-0.44
J.D. Martinez25.7926.81.015.547.41.86
Nick Castellanos24.4324.80.375.226.41.18
Michael Morse25.5828.32.725.395.80.41
Rene Rivera23.9425.11.164.973.8-1.17
Wilin Rosario26.6923.2-3.495.541.8-3.74
Evan Gattis2524-14.974-0.97
Ben Paulsen24.8322.5-2.334.937.92.97
Yasmany Tomas21.7921.90.114.24.90.7
Joey Butler26.2426.80.564.972.9-2.07
Nolan Arenado20.0914.6-5.493.744.20.46
Marlon Byrd25.4124.9-0.514.648.63.96
Starling Marte23.123.20.14.175.21.03
Carlos Gomez22.9322.9-0.034.143.6-0.54
Scooter Gennett18.4623.24.743.253.2-0.05
Chris Owings22.8625.22.3442.6-1.4
Ryan Howard29.1929.1-0.095.114.6-0.51
Clint Barmes24.9530.85.854.314.40.09
Danny Santana21.6926.14.413.741.1-2.64
Alex Guerrero21.6824.62.923.673.80.13
Eddie Rosario26.1325.2-0.934.384.3-0.08
Hector Gomez26.1229.63.484.292.6-1.69
Adam Jones19.114-5.13.14.71.6
Randal Grichuk29.930.10.24.442.7-1.74
Jimmy Paredes30.5125.5-5.014.313.9-0.41
Sean Rodriguez26.1925.3-0.893.571.1-2.47
Avisail Garcia28.6425.3-3.343.755.82.05
Oswaldo Arcia30.0423.1-6.943.896.22.31
Christian Bethancourt25.7217.3-8.423.22.9-0.3
Delmon Young25.6716.4-9.272.972.4-0.57

As we can see, some prominent MLB hitters could be looking at an uptick in strikeouts, such as Hunter Pence and Justin Morneau. As well, former Blue Jay Emilio Bonifacio and Tampa Bay Rays slugger Steven Souza have been getting “unlucky” with their strikeouts, and could see a decrease in the near future. Meanwhile, xBB% is not buying into two of the better hitters in the league right now, predicting Bryce Harper and Miguel Cabrera for sharp downticks in walk rate, whereas it predicts Geovany Soto and JJ Hardy to be among the players who could see a few more walks come their way.

Next up, Breaking Blue will take a look at xBABIP.

Looking for Inefficiencies in MLB Draft Demographics | A Study
Using StatCast and BIS Batted Ball Data to Assess Expected Power Output

Author: Jacob Danovitch

Jacob has been following baseball since he fell in love with it going to a baseball game at the age of four. He's played baseball from the age of six and plays competitive basketball as well. He fell in love with the sabermetric side of baseball after arguing about Yunel Escobar with a friend and using advanced stats to prove his case. Jacob enjoys music and reading in his little free time as well. He is a fan of the Maple Leafs, Raptors and Bills.

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2 Comments

  1. I just was reading this from reddit, so I figured I’d throw this to the author. Just my thoughts and speculation, but one thing that this formula might miss is a full representation of patience at the plate. Guys like Carlos Santana take a ton of pitches, probably more than he ought to, so his K% and BB% are both elevated from his expected numbers. He has the zone control and contact skills to strike out less, but he’d rather leave the bat on his shoulders in late counts.

    As opposed to the Adam Jones school of hitting, where the batter knows he’s easy to put away in 2-strike counts, so he swings excessively early at anything in the zone hoping for a good outcome. This can be a good strategy for guys with bad oSwing% and high SwStr% rates, since while it theoretically reduces their walk rate, but you have to remember that these guys would never run a good walk rate anyway.

    See: http://espn.go.com/mlb/stats/batting/_/league/al/sort/pitchesPerPlateAppearance/type/expanded/order/true

    Quick cherry-picked examples:

    Carlos Santana:
    xK% 12.48%
    K% 15.6%
    xBB% 14.56%
    BB% 19.1%
    P/PA 4.37, 2nd highest in the league

    Adam Jones:

    xK% 19.1%
    K% 14%
    xBB% 3.1%
    BB% 4.7%
    P/PA 3.37, 5th lowest in the league

    Weirdly, Adam Jones’ SwStr% rate is way down this year, so he’s not even the best example of his own hitting philosophy.

    Post a Reply
    • Thanks for the reply! P/PA is an interesting idea. You make a good point; my model may well not capture players on either side of the extremes of P/PA. I will look into how this can be incorporated into future editions of my model. Thank you for the input.

      Post a Reply

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