
Masahiro Tanaka has carried the Yankee staff this season thanks to his league-leading Swinging Strike Rate.
When looking at early season statistics, it’s important to see what can be sustained and what cannot. A third of the season is already in the books, and when it comes to projecting the final two thirds of the year only one thing is certain: some players will regress from unrealistic paces, and others will improve from slow starts to the season.
One way to see what pitchers have under or over-performed is in their strikeout rate. Theoretically, the correlation between the amount of swing-and-misses a pitcher gets and the amount of strikeouts they get should be nearly 1 – however, strike outs looking, “clutch” swing-and-miss pitches on strike 3, and pure variance will lead to a much lower correlation. I took a look at this year’s 102 qualified pitchers and compared their K% rate and their SwStr% rate:
I created the “expected K%”, or xK%, for each pitcher by normalizing their swinging strike rate to the yellow line on the graph, which shows the best-fit line of the data for all 102 qualified pitchers. This is what in the long-run will be the average K rate of a pitcher with that given swinging strike rate. While some pitchers may be better at getting strikeouts looking or reaching back for a swing-and-miss on strike 3, this is where most pitchers should end up. The correlation so far this year is at .55, while last year at the end of the year the correlation was .72. This shows how pitchers over a larger sample will be closer and closer to the line.
This brings us to the final statistic, K%-xK%. This shows where a pitcher’s been “lucky” or “unlucky,” with high numbers pointing to pitchers that are performing over their heads, and negative numbers pointing to pitchers that should be striking out more batters the rest of the way. All of the data I compiled is in a sort-able table below:
Name Team SwStr% K% xK% K%-xK%
Masahiro Tanaka Yankees 14.30% 28.70% 28.91% -0.21%
Francisco Liriano Pirates 14.20% 23.00% 28.75% -5.75%
Tyson Ross Padres 12.60% 22.20% 26.10% -3.90%
Ervin Santana Braves 12.40% 22.40% 25.76% -3.36%
Stephen Strasburg Nationals 12.30% 28.50% 25.60% 2.90%
Zack Greinke Dodgers 12.20% 28.30% 25.43% 2.87%
Felix Hernandez Mariners 12.10% 24.80% 25.27% -0.47%
Corey Kluber Indians 11.90% 28.40% 24.94% 3.46%
Michael Wacha Cardinals 11.90% 25.20% 24.94% 0.26%
Madison Bumgarner Giants 11.80% 27.50% 24.77% 2.73%
Max Scherzer Tigers 11.60% 27.70% 24.44% 3.26%
Yordano Ventura Royals 11.40% 24.30% 24.11% 0.19%
Edwin Jackson Cubs 11.20% 22.30% 23.78% -1.48%
Jason Hammel Cubs 11.00% 22.70% 23.44% -0.74%
Dallas Keuchel Astros 10.90% 21.50% 23.28% -1.78%
Julio Teheran Braves 10.90% 20.30% 23.28% -2.98%
John Lackey Red Sox 10.80% 22.70% 23.11% -0.41%
Jorge de la Rosa Rockies 10.60% 19.70% 22.78% -3.08%
Alex Wood Braves 10.50% 25.00% 22.61% 2.39%
Jordan Zimmermann Nationals 10.50% 19.40% 22.61% -3.21%
R.A. Dickey Blue Jays 10.40% 18.90% 22.45% -3.55%
Yu Darvish Rangers 10.20% 29.50% 22.12% 7.38%
David Price Rays 10.20% 25.60% 22.12% 3.48%
Garrett Richards Angels 10.10% 23.30% 21.95% 1.35%
Homer Bailey Reds 10.10% 19.90% 21.95% -2.05%
Aaron Harang Braves 9.90% 24.20% 21.62% 2.58%
Jon Lester Red Sox 9.80% 29.10% 21.45% 7.65%
Ian Kennedy Padres 9.80% 27.00% 21.45% 5.55%
Hiroki Kuroda Yankees 9.80% 17.30% 21.45% -4.15%
Marco Estrada Brewers 9.70% 22.80% 21.29% 1.51%
Scott Kazmir Athletics 9.70% 19.90% 21.29% -1.39%
Matt Garza Brewers 9.70% 19.30% 21.29% -1.99%
Tim Hudson Giants 9.70% 16.80% 21.29% -4.49%
Josh Beckett Dodgers 9.50% 23.60% 20.96% 2.64%
Tim Lincecum Giants 9.50% 22.90% 20.96% 1.94%
Jason Vargas Royals 9.50% 18.50% 20.96% -2.46%
Drew Hutchison Blue Jays 9.40% 21.70% 20.79% 0.91%
Jeff Samardzija Cubs 9.40% 21.00% 20.79% 0.21%
Justin Masterson Indians 9.40% 19.00% 20.79% -1.79%
Johnny Cueto Reds 9.20% 26.70% 20.46% 6.24%
James Shields Royals 9.20% 20.70% 20.46% 0.24%
Justin Verlander Tigers 9.20% 16.50% 20.46% -3.96%
Roenis Elias Mariners 9.10% 21.30% 20.29% 1.01%
Adam Wainwright Cardinals 9.00% 24.70% 20.13% 4.57%
Wade Miley Diamondbacks 8.90% 21.00% 19.96% 1.04%
Phil Hughes Twins 8.80% 19.90% 19.80% 0.10%
Tom Koehler Marlins 8.80% 15.90% 19.80% -3.90%
Jesse Chavez Athletics 8.70% 22.70% 19.63% 3.07%
Kyle Lohse Brewers 8.70% 19.70% 19.63% 0.07%
Zack Wheeler Mets 8.60% 22.70% 19.47% 3.23%
Miguel Gonzalez Orioles 8.60% 19.80% 19.47% 0.33%
Gerrit Cole Pirates 8.50% 20.80% 19.30% 1.50%
Sonny Gray Athletics 8.50% 19.70% 19.30% 0.40%
Jered Weaver Angels 8.50% 18.00% 19.30% -1.30%
Chris Archer Rays 8.40% 21.60% 19.13% 2.47%
Brandon McCarthy Diamondbacks 8.40% 20.50% 19.13% 1.37%
Lance Lynn Cardinals 8.40% 19.80% 19.13% 0.67%
Rick Porcello Tigers 8.40% 16.30% 19.13% -2.83%
Juan Nicasio Rockies 8.40% 14.80% 19.13% -4.33%
Wei-Yin Chen Orioles 8.30% 17.00% 18.97% -1.97%
Ricky Nolasco Twins 8.30% 14.70% 18.97% -4.27%
Jake Peavy Red Sox 8.20% 17.60% 18.80% -1.20%
John Danks White Sox 8.20% 16.60% 18.80% -2.20%
Cliff Lee Phillies 8.10% 21.10% 18.64% 2.46%
Wily Peralta Brewers 8.00% 18.60% 18.47% 0.13%
Tyler Skaggs Angels 8.00% 18.30% 18.47% -0.17%
Nathan Eovaldi Marlins 7.90% 19.60% 18.31% 1.29%
Alfredo Simon Reds 7.90% 15.10% 18.31% -3.21%
Franklin Morales Rockies 7.90% 15.10% 18.31% -3.21%
Jose Quintana White Sox 7.80% 19.40% 18.14% 1.26%
C.J. Wilson Angels 7.70% 22.60% 17.97% 4.63%
Hyun-Jin Ryu Dodgers 7.70% 20.80% 17.97% 2.83%
Ryan Vogelsong Giants 7.70% 19.40% 17.97% 1.43%
A.J. Burnett Phillies 7.60% 19.80% 17.81% 1.99%
Edinson Volquez Pirates 7.60% 16.10% 17.81% -1.71%
Chris Tillman Orioles 7.40% 17.50% 17.48% 0.02%
Josh Collmenter Diamondbacks 7.40% 15.50% 17.48% -1.98%
Kyle Kendrick Phillies 7.40% 14.00% 17.48% -3.48%
Kyle Gibson Twins 7.40% 12.00% 17.48% -5.48%
Shelby Miller Cardinals 7.30% 17.20% 17.31% -0.11%
Ubaldo Jimenez Orioles 7.20% 21.60% 17.14% 4.46%
Tanner Roark Nationals 7.20% 17.80% 17.14% 0.66%
Mike Leake Reds 7.20% 16.20% 17.14% -0.94%
Travis Wood Cubs 7.10% 20.30% 16.98% 3.32%
Tommy Milone Athletics 7.00% 15.20% 16.81% -1.61%
Henderson Alvarez Marlins 7.00% 14.20% 16.81% -2.61%
Andrew Cashner Padres 6.90% 19.30% 16.65% 2.65%
Dan Haren Dodgers 6.90% 17.30% 16.65% 0.65%
Eric Stults Padres 6.80% 11.50% 16.48% -4.98%
Charlie Morton Pirates 6.70% 15.30% 16.32% -1.02%
Jordan Lyles Rockies 6.60% 16.90% 16.15% 0.75%
Bud Norris Orioles 6.60% 15.60% 16.15% -0.55%
Bronson Arroyo Diamondbacks 6.30% 13.10% 15.65% -2.55%
Jon Niese Mets 6.20% 17.80% 15.49% 2.31%
Mark Buehrle Blue Jays 6.00% 13.90% 15.16% -1.26%
Jeremy Guthrie Royals 6.00% 11.80% 15.16% -3.36%
Bartolo Colon Mets 5.90% 18.70% 14.99% 3.71%
Jarred Cosart Astros 5.90% 15.40% 14.99% 0.41%
Chris Young Mariners 5.60% 11.70% 14.49% -2.79%
Yovani Gallardo Brewers 5.50% 16.60% 14.33% 2.27%
Kevin Correia Twins 4.50% 12.50% 12.67% -0.17%
Click the category atop each column to sort by that and click the arrows at the bottom right corner to go to the next page of data.
As you can see, there is a wide spread of over and under achievers among elite and sub-par pitchers. The highest K%-xK%’s belonged to Jon Lester (7.65%), Yu Darvish (7.38%), and Johnny Cueto (6.24%). All three should remain effective pitchers, but expect their elite K rates to drop a little bit, and Lester in particular could be a good sell-high candidate.
On the other side of the spectrum, some of the pitchers who should see a rise in strikeouts include Francisco Liriano (-5.75%), Hiroki Kuroda (-4.15%), and Justin Verlander (-3.96%), which is great news for their fantasy owners and makes them a good target in a trade. Tyson Ross is another name that pops up on the list, due to his 12.60% Swinging Strike rate, good for 3rd in the league. He is undervalued right now in nearly every league, and is becoming one of my favorite young arms due to his ability to generate lots of strikeouts and ground balls.
This list should be a good way to study strikeout rates across the league and project the pitchers that will improve or decline the rest of the way, but is far from a definitive projection. Some pitchers will continue to show an ability to maintain their extreme rate (be it higher or lower than the average).
Matt Cott is a co-founder of RotoAnalysis. Follow him on Twitter @RotoAnalysis and @KidCotti21!
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