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Fantasy Baseball: Using Expected Strikeout Rate To Find Strikeout Gainers/Losers

We finally have baseball games on TV again! Spring training games are back, transactions are taking place, and Opening Day is soon upon us. It truly is the best time of the year!

With the lockout over, fantasy baseball drafts are picking up in full swing. Thus, time is running out to conduct our fantasy baseball prep for the upcoming season. We need to solidify our evaluation of players from a fantasy perspective, making now the last time to get in any information before we are on the clock!

To help with this, I thought we would all benefit from taking a look at underlying pitcher data! It can be so difficult to project pitcher performance from season to season, so gaining any sort of edge ahead of the competition here can be crucial.

We tend to think of strikeout rate for pitchers as a stable statistic, and for good reason; its coefficient of determination from season-to-season (r^2=.57) suggests a strong relationship when using last year’s strikeout rate to project next year’s strikeout rate. That being said, there are some cases where pitchers overperform or underperform where their strikeout rate SHOULD be, leading to potential regression the following season.

That led me to create a tool to identify who these players may be: expected strikeout rate. Using data such as chase rate, whiff rate, swinging-strike rate, and called-strike-whiff rate (CSW%), I was able to create a weighting system by testing the correlation of each of these variables when it comes to predicting NEXT year’s strikeout rate. After all, we’re looking for it be predictive, whereas most expected statistics are descriptive.

After testing the correlations of each of the variables and creating a weighting system, expected strikeout rate was born! Going back to 2014, it has quite a strong relationship (r^2= .77) with that year’s strikeout rate, but it wasn’t as predictive (r^2=.434) as previous strikeout rate. However, by weighting previous strikeout rate at 57% and projected strikeouts at 43%, it became slightly more predictive in terms of projecting future strikeout rate.

You can get by projecting future strikeout rate by using past strikeout rate. However, there are some cases where it may not be as helpful. For starters, what if the player has a limited sample size? Their strikeout rate could be skewed in one way or another, meaning that the underlying metrics will better determine their overall true talent. Or, what if they simply were an outlier? Being able to find which players clearly deserved better or worse strikeout rates can be critical when finding potential overvalued or undervalued pitchers.

Today, we’ll be taking a look at which pitchers overachieved and underachieved last season, based on their strikeout rate. By the end of this, we should be able to solidify our evaluation of certain pitchers, whether strengthening our case for them or giving more reason to potentially be wary of them. So, who ends up on each end of the spectrum? Let us find out!

Rejoice! There will be baseball in 2022! Why not celebrate with one of our Fantrax Classic Draft contest? Get a jump on the season with a Best Ball league or maybe a Draft and Hold. Or put some green on the line with a new season-long league to try and conquer. There’s no better time than now to get your baseball on!

Expected Strikeout Rate (xK%)

Pitchers Who Overachieved Their xK%

NameK%Projected K%Diff
Zac Gallen26.60%19.96%6.64%
Nick Pivetta26.40%21.84%4.56%
Lance Lynn27.50%23.13%4.37%
Zack Wheeler29.10%25.01%4.09%
Jose Berrios26.10%22.24%3.86%
Carlos Rodon34.60%30.75%3.85%
Trevor Bauer31.70%27.91%3.79%
Chris Bassitt25.00%21.56%3.44%
Tarik Skubal26.20%22.81%3.39%
Erick Fedde21.80%18.42%3.38%
Pablo Lopez27.50%24.30%3.20%
Blake Snell30.90%27.75%3.15%
Adrian Houser17.10%13.97%3.13%
Eduardo Rodriguez27.40%24.32%3.08%
Mitch Keller19.60%16.63%2.97%
Jake Odorizzi20.60%17.67%2.93%
Yu Darvish29.20%26.32%2.88%
J.A. Happ18.20%15.34%2.86%
Brandon Woodruff29.80%27.11%2.69%
Tyler Mahle27.70%25.07%2.63%
Shohei Ohtani29.30%26.73%2.57%
Sonny Gray27.00%24.58%2.42%
Ross Stripling22.80%20.46%2.34%
Jake Arrieta17.70%15.45%2.25%
Tylor Megill26.10%23.86%2.24%
Triston McKenzie27.30%25.21%2.09%
Gerrit Cole33.50%31.45%2.05%
Steven Matz22.30%20.33%1.97%
Freddy Peralta33.20%31.30%1.90%
Julio Urias26.20%24.32%1.88%
Eric Lauer23.00%21.12%1.88%
Kyle Freeland20.40%18.55%1.85%
Aaron Nola29.80%27.99%1.81%
Jorge Lopez19.50%17.77%1.73%
Cal Quantrill20.00%18.27%1.73%
Alek Manoah27.70%25.97%1.73%
Martin Perez19.10%17.53%1.57%
Logan Gilbert25.40%23.83%1.57%
Kris Bubic20.60%19.03%1.57%
Bailey Ober25.30%23.74%1.56%
Kolby Allard17.40%15.84%1.56%
Merrill Kelly19.50%18.25%1.25%
Robbie Ray32.10%30.86%1.24%
Jacob deGrom45.10%43.88%1.22%
Max Scherzer34.10%32.92%1.18%
Johnny Cueto19.80%18.62%1.18%
Andrew Heaney27.50%26.39%1.11%
Taijuan Walker22.20%21.11%1.09%
Adam Wainwright21.00%19.92%1.08%
Walker Buehler26.00%24.97%1.03%
Matt Manning14.80%13.81%0.99%
Charlie Morton28.60%27.70%0.90%
Michael Wacha22.70%21.80%0.90%
Alec Mills17.00%16.14%0.86%
Brad Keller19.60%18.81%0.79%
Sean Manaea25.70%25.05%0.65%
Jon Gray24.40%23.78%0.62%
Dylan Cease31.90%31.28%0.62%
Zach Eflin22.40%21.86%0.54%
Max Fried23.70%23.18%0.52%
Matt Harvey16.30%15.81%0.49%
Aaron Civale19.90%19.44%0.46%
Chris Flexen16.90%16.49%0.41%
Paolo Espino20.00%19.62%0.38%
James Kaprielian24.20%23.87%0.33%
Mike Foltynewicz16.50%16.18%0.32%
Mike Minor22.30%22.03%0.27%
Brett Anderson14.20%13.99%0.21%
Rich Hill22.70%22.65%0.05%
Eli Morgan21.40%21.36%0.04%

Zac Gallen, Arizona Diamondbacks

Right now, there may not be a tougher pitcher to evaluate than Zac Gallen. Over the first 152 innings of his career, he was able to put batters away with a 28.5% strikeout rate and a 12.5% swinging-strike rate, and was expected to ascend into an ace.

In some aspects, the 26-year-old still performed strongly. His 26.6% strikeout rate was still above-average, while his ERA indicators (4.04 skill-interactive ERA, SIERA) were right on par with previous seasons. Sure, his 4.30 ERA wasn’t ideal, but many of his ERA estimators considered that this was due to natural variance that was due to get better.

This doesn’t tell the whole story, however. Quietly, his swinging-strike rate fell to 9.1%, which was over three percentage points lower than his previous swinging-strike rate; his 27% CSW was also over four percentage points lower than his career rate. With that in mind, it’s a shock that we was able to keep such a high strikeout rate.

If something doesn’t change for Gallen this year, we should expect his strikeout rate to drop further. So, the question is: why did he struggle to miss bats this season? To start, let’s take a look at his pitch mix:

Gallen’s fastball does a nice job inducing pop-ups, but he threw it an exceptionable amount of the time, especially considering his off-speed pitches are strong. Meanwhile, simply didn’t get the results he was looking for from his top pitches:

Gallen threw his cutter much less in 2020, and added more drop to it. That doesn’t appear to have been a very effective change, but what all of this comes down to his pitch location. Let’s take a look at his average pitch height on his fastball per year:

As you can see, Gallen has really gone towards an approach establishing the bottom of the zone. My hypothesis is that this led to hitters chasing less pitches outside the zone (25.7%), as hitters were centered on one specific part of the zone. With a very vertical arsenal, there is no reason he shouldn’t be utilizing a traditional north-south approach.

Luckily, with former Astros pitching coach Brett Storm taking over with the same role in Arizona, Gallen has the perfectness voice he needs to make the changes he needs to. Considering he was dealing with multiple injuries last year, I’m willing to write off some of last year’s issues due to that. That being said, the developments from last season were still concerning. Hopefully, we get the best version of Gallen next season!

Chris Bassitt, New York Mets

It’s not often a pitcher bursts onto the scene as a 30-year-old and then has a true breakout season at age 32. Well, I guess you can call Chris Bassitt a late bloomer.

Between 2019 and 2020, Bassitt did post a 3.35 ERA, but it came with some worrisome indicators. His skill interactive ERA (SIERA), a top ERA estimator, was a full run (4.47) over the ERA, while his 22.5% strikeout rate was below-average. Coming into the season, the expectation was that he’d face serious regression.

Instead, Bassitt hit new levels, posting a 3.15 ERA. Meanwhile, his 25.1% strikeout rate and 10.1% swinging-strike rate were career-high marks; this was truly his best season yet. Now, will it be repeated?

Based on his expected strikeout rate, perhaps not, but these numbers may be skewed a bit. Bassitt throws a fastball (4-seam, cutter, sinker) on 73.2% of his pitches, an extremely high number. With a 54.2% zone rate, he certainly is pounding the zone early, looking to set up put-away spots using his premier whiff pitches.

When a batter is behind in the count, Bassitt’s fastball rate drops to 57.9%, while his slider (17.5%) becomes his second-used pitch. Considering his slider and curveball-induced whiff rates of 38.7% and 38.8%, respectively, they are definitely pitches he can count on when ahead. This strategy is working right now, though one could wonder if Bassitt would have a significantly better chance of repeating his production from last year with more usage of his breaking balls.

Luckily, Bassitt has an opportunity to get a new perspective with his new organization. If he was going to leave Oakland, this is a great fit for him from a defense and ballpark perspective. Now, we’ll see what he does to try to replicate the strikeout production from last season.

Jose Berrios, Toronto Blue Jays

I think it’s safe to say the Blue Jays have very high expectations this season. Sure, the lineup plays a large role with that, but this is also one of the best rotations in baseball. Kevin Gausman has flourished into a true ace, Alek Manoah is one of the league’s better young pitchers, Hyun-Jin Ryu could easily bounce back, while Yusei Kikuchi has plenty of upside if his fastball velocity is there.

The key, however? Jose Berrios. Since his first full season in 2017, Berrios has established himself as a steady low-end #2/high-end #3 pitcher. During that time, he has a 3.74 ERA, 4.02 SIERA, and 24.4% strikeout rate. Last season, though, he posted a career-high 26.1% strikeout rate and 3.52 ERA. As a former top prospect who seemed destined to ascend into being an ace at this point, was this the first step towards a breakout?

I’m not sure. Berrios had a career-high strikeout rate, but his swinging-strike rate of 9.9% was the lowest it has been since 2017. Instead, he relied on called-strikes (19.2%) to fuel his success. Is that a sustainable formula? That is the question we’re trying to answer.

Berrios has made a lot of adjustments throughout his career. As you can see, he started out as a “four-seam heavy” pitcher, but has shifted towards his sinker recently

Berrios’s sinker is definitely productive when it comes to producing called strikes, but called strikes can be volatile on a year-to-year basis. He doesn’t walk many batters, and has established himself as a pretty steady pitcher. However, for those hoping for a big “breakout” or even a repeat in last year’s strikeout rate, it’s easy to see why the projections are slightly pessimistic.

Pitchers Who Underachieved Their xK%

NameK%Projected K%Diff
Domingo German23.20%29.04%-5.84%
Clayton Kershaw29.50%35.10%-5.60%
Dallas Keuchel13.00%18.39%-5.39%
Zach Plesac16.70%22.05%-5.35%
Jesus Luzardo22.50%26.76%-4.26%
Shane McClanahan27.30%31.26%-3.96%
Patrick Corbin19.00%22.96%-3.96%
Tyler Anderson19.10%22.65%-3.55%
Ryan Yarbrough17.60%21.03%-3.43%
Jordan Montgomery24.50%27.70%-3.20%
Marcus Stroman21.60%24.63%-3.03%
Lucas Giolito27.90%30.84%-2.94%
Kyle Hendricks16.70%19.57%-2.87%
Michael Pineda19.10%21.94%-2.84%
Corey Kluber24.00%26.78%-2.78%
Kenta Maeda24.90%27.63%-2.73%
Jose Urquidy21.30%23.90%-2.60%
Zack Greinke17.00%19.59%-2.59%
Dylan Bundy20.30%22.87%-2.57%
Luis Castillo23.90%26.43%-2.53%
Wade Miley18.10%20.59%-2.49%
Wily Peralta14.40%16.83%-2.43%
Jon Lester14.50%16.90%-2.40%
Alex Wood26.00%28.38%-2.38%
Shane Bieber33.10%35.42%-2.32%
Sandy Alcantara24.00%26.31%-2.31%
Drew Smyly21.80%24.10%-2.30%
Vladimir Gutierrez17.70%20.00%-2.30%
Zach Davies17.10%19.33%-2.23%
Austin Gomber23.20%25.39%-2.19%
Kevin Gausman29.30%31.32%-2.02%
Jordan Lyles19.40%21.28%-1.88%
Huascar Ynoa27.20%29.01%-1.81%
Luis Garcia26.30%28.06%-1.76%
German Marquez23.30%25.01%-1.71%
Carlos Martinez15.70%17.39%-1.69%
Chris Paddack21.20%22.87%-1.67%
Frankie Montas26.60%28.19%-1.59%
Yusei Kikuchi24.50%26.09%-1.59%
Kyle Gibson20.80%22.36%-1.56%
Jose Urena14.20%15.72%-1.52%
Kwang-hyun Kim18.10%19.56%-1.46%
John Gant18.10%19.53%-1.43%
Brady Singer22.40%23.82%-1.42%
Ian Anderson23.20%24.58%-1.38%
Antonio Senzatela15.70%17.05%-1.35%
JT Brubaker24.00%25.34%-1.34%
Joe Musgrove27.30%28.63%-1.33%
Logan Webb26.50%27.81%-1.31%
Framber Valdez21.90%23.18%-1.28%
Hyun-Jin Ryu20.40%21.63%-1.23%
Cole Irvin16.30%17.51%-1.21%
Trevor Rogers28.50%29.61%-1.11%
Jameson Taillon23.20%24.24%-1.04%
Chi Chi Gonzalez12.50%13.53%-1.03%
Garrett Richards17.30%18.22%-0.92%
John Means22.70%23.56%-0.86%
Nathan Eovaldi25.50%26.30%-0.80%
Casey Mize19.30%20.04%-0.74%
Alex Cobb24.90%25.63%-0.73%
Joe Ross24.50%25.14%-0.64%
Corbin Burnes35.60%36.21%-0.61%
Adbert Alzolay24.10%24.59%-0.49%
Madison Bumgarner20.20%20.66%-0.46%
Tyler Glasnow36.20%36.63%-0.43%
Lance McCullers Jr.27.00%27.35%-0.35%
Vince Velasquez22.80%23.14%-0.34%
Anthony DeSclafani22.50%22.83%-0.33%
Dane Dunning21.90%22.21%-0.31%
Wil Crowe21.00%21.28%-0.28%
Marco Gonzales18.50%18.70%-0.20%

Shane McClanahan, Tampa Bay Rays

When many think of the Rays, the attention goes to their bullpen or different strategies. However, whether it’s Charlie MortonBlake SnellTyler Glasnow, or even David Price in his prime, they’ve always had an “ace” that they can rely on.

With Glasnow out for the season after undergoing Tommy John surgery, the onus will be on Shane McClanahan to assume that role. Through the minors, McClanahan was seen as a pitcher with an electric pitching arsenal, but someone who was likely a reliever. Well, we saw plenty of that arsenal, but as a starter.

In 123.1 innings last season, McClanahan had a 27.3% strikeout rate, 3.62 SIERA, and a 20.1% K-BB ratio. If he can just repeat those numbers, that would be quite exciting. Yet, there may be more on the table.

See, McLanahan’s underlying numbers are even better than his surface-level strikeout rate. Among starting pitchers with 120 innings pitched, McClanahan ranked 9th in swinging-strike rate (14.8%), 6th in CSW% (31.5%), and had the 10th-lowest opponent contact rate (70.4%). Yet, his strikeout rate ranked just 23rd. All told, he had the sixth-highest expected strikeout rate, which could point to notable improvement next season.

McClanahan has three elite pitches in his slider (39.9% whiff), curveball (41.9% whiff), and changeup (44.8%). That gives him quite the deep arsenal to work with, and he demonstrated the ability to go deeper into games. There are some issues with his fastball, which got hit hard despite sitting over 96 MPH with it, but the bat-missing abilities are legitimate.

He may be somewhat limited with innings, but there’s a world where the Rays lean on McClanahan more than we expect last year. The strikeout abilities are real, and there’s so much room for growth. Simply put, I’m quite optimistic about his future as a premier frontline starter.

Jesus Luzardo, Miami Marlins

Ever since he was the main centerpiece in a trade that sent relievers Sean Doolittle and Ryan Mason to the Nationals in 2017, Jesus Luzardo worked his way into prospect stardom.

By 2019, Luzardo was MLB Pipeline‘s #2 pitching prospect and #12 overall prospect. After he held up well in 2020 with a 4.05 SIERA in his rookie debut, expectations were high for him in 2021- he was expected to be the team’s ace. Going by his NFBC Main Event average draft position (ADP), he was a top-25 pitcher in terms of where he was being drafted!

Of course, this did not go as planned. With the A’s and Marlins, he posted a 6.61 ERA, along with a 4.72 SIERA, and just a 22% strikeout rate with an 11% walk rate. Between initially struggling with Oakland to hurting hand raging from a video game to being demoted to the minors to being traded to Miami for Starling Marte, it truly was a tumultuous season for the 24-year-old.

Fortunately, there are signs of hope for the future. See, when Luzardo was traded to the Marlins, his overall numbers were not pretty (6.44 ERA, 4.96 SIERA, 22% strikeout rate, 11.1% walk rate), but there were signs it was coming together. See, Luzardo’s four-seam fastball and sinker each allowed weighted on-base averages (wOBA) over .420 last year. On the other hand, his curveball and changeup each had whiff rates over 35%. Upon being traded to Miami, he started to lean into his best pitches:

  • With Oakland: 59.2% Fastball, 21.1% Breaking Ball, 19.3% Changeup
  • With Miami: 46.4% Fastball, 33.4% Breaking Ball, 20.2% Changeup

Sure, Luzardo’s strikeout rate and results weren’t great, but it came with an elevated 13.6% swinging-strike rate, 28.4% whiff rate, and a 33.4% outside-zone swing percentage; all above-average rates. His command (12.1% walk rate) got in the way of that translating to more strikeouts, but I’m optimistic about that changing in the future. His projected strikeout rate crosses the barrier from below average to above average, and could play a role in him bouncing back next season.

As a late-round dart throw, Luzardo offers a lot of upside. He’ll now have had a full offseason to get used to the new pitch mix, which should help his command, while he’ll be playing in a great ballpark. The floor here is quite low, but the talent is still there. With little risk and a clear reward, why not take a shot on him?

Jordan Montgomery, New York Yankees

Every time an injury happens in sports, I wish even more than we could simply ban it from our existence. However, they are a part of the game, and few can attest to this like Jordan Montgomery.

After a productive rookie season with a 4.07 FIP in 155.1 innings pitched, there was reason to be optimistic about Montgomery as a nice piece for the Yankees to have in their rotation. Then, he went on to pitch a combined 31.1 innings in 2018 and 2019 after undergoing Tommy John surgery.

In 2020, Montgomery returned strong with a 3.84 SIERA and 19.7% K-BB ratio during the shortened season. He wasn’t necessarily guaranteed a rotation spot in 2021 and wasn’t a highly-drafted commodity, but he certainly built off that success. In 157.1 innings, he posted a 3.89 ERA and a 3.69 FIP, along with a 4.07 SIEA and 24.5% strikeout rate. Overall, he was exactly what the Yankees were hoping he could be.

The best part? There is reason to believe in further growth for Montgomery in 2021. While his strikeout rate stayed at the same rate it was during 2020, his swinging-strike rate moved up to 13.7%. That ranked 14th among pitchers with at least 120 innings, while he allowed the 17th-lowest contact rate (72.7%) as well.

What caused this spike in success? Better pitch usage. Montgomery continued to decrease the usage of his sinker (21.9%), utilizing a cutter (13.8%) more to induce more whiffs. Meanwhile, his changeup (39.2% whiff) and curveball (42.9% whiff rate), two elite pitches, were his top-two utilized offerings. A balanced five-pitch mix with confidence in two tremendous off-speed pitches certainly is a way to miss bats.

Based on Montgomery’s underlying data, a 24.5% strikeout rate almost seems like the floor for him. If you’re looking for a middle-round target to help round out your pitching staff with strikeout upside, he’s a great target. He may not be Mike, but this Jordan should be in line for the best season of his career in 2022.

For more great analysis and rankings, make sure to check out the 2022 FantraxHQ Fantasy Baseball Draft Kit!
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