Earlier this week, I was reading Michael Ajeto's article on PitcherList about Brady Singer. In the article, Michael touted Singer's deception and mentioned a sign of that being Singer's Zone Swing Rate (Z-Swing%) minus his Chase Rate (O-Swing%). The premise of the concept was simple but one that stood out to me immediately.
Z-Swing% measures the rate at which hitters swing at pitches a pitcher delivers in the zone for a strike. While hitters will sometimes take a pitch early in the count if it's not what they're looking for, a pitcher with a low Z-Swing% is likely consistently fooling batters either with the specific pitch type or location. O-Swing% is the rate at which batters swing at pitches outside of the zone, so if a pitcher induces a high O-Swing% then he is usually fooling batters either with pitch location, movement, or mix.
It should go without saying that when hitters swing at pitches out of the zone, they are less likely to make contact and if they do, it's far less likely to be good contact. Since both metrics seem to measure a pitcher's ability to deceive hitters, looking at them in relation to one another makes sense. The closer the two numbers are (low Z-Swing% and high O-Swing%) the more deception we can assume a pitcher is overall. The idea makes sense on the surface, and, when I created the leaderboard of Z-O%, the results seemed to support the idea that a low Z-O% would indicate a more deceptive pitcher.
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Z-O% Swing Top-20 Leaderboard
Leaderboard uses stats from July 1st, 2019 through the end of the 2020 season to approximate a full season.
Name | Team | Z-Swing% | O-Swing% | Z-O% |
Lance McCullers Jr. | Astros | 55.90% | 30.00% | 25.90% |
Aaron Nola | Phillies | 63.00% | 36.90% | 26.10% |
Zac Gallen | Diamondbacks | 60.40% | 33.90% | 26.50% |
Jose Berrios | Twins | 63.40% | 35.90% | 27.50% |
Stephen Strasburg | Nationals | 64.00% | 36.10% | 27.90% |
Miles Mikolas | Cardinals | 66.90% | 38.40% | 28.50% |
Dylan Bundy | Angels | 63.70% | 35.10% | 28.60% |
Brady Singer | Royals | 58.30% | 29.40% | 28.90% |
Tommy Milone | Free Agent | 66.90% | 37.70% | 29.20% |
Ryan Yarbrough | Rays | 68.30% | 38.90% | 29.40% |
Yu Darvish | Padres | 65.90% | 36.30% | 29.60% |
Zack Greinke | Astros | 62.40% | 32.30% | 30.10% |
Sonny Gray | Reds | 60.00% | 29.70% | 30.30% |
Marco Gonzales | Mariners | 65.60% | 35.10% | 30.50% |
Gio Gonzalez | Free Agent | 63.30% | 32.70% | 30.60% |
Kyle Hendricks | Cubs | 67.70% | 36.90% | 30.80% |
Not only does the list above contain some of the game's best control pitchers, like Zack Greinke and Kyle Hendricks, but it also contains pitchers like Yu Darvish and Aaron Nola with plus off-speed offerings that often keep hitters guessing. To top it off, this metric seems to also flag those overlooked pitchers, like Tommy Milone and Gio Gonzalez, whose results are inconsistent but can trace almost all of their success back to deception while also leaving off elite arms like Jacob deGrom and Gerrit Cole, who do most of their damage by over-powering hitters and, thus, rely less on deception.
If we can identify which pitchers are most likely to consistently deceive hitters, we are not only identifying good pitchers but also pitchers who are being undervalued based on projections. Since deception is hard to quantify as a trait, many deceptive pitchers tend to outperform the projection systems.
So, the premise of this article is that, if we can identify deceptive pitchers who may outperform their predictive metrics, then we can potentially identify pitchers who will outperform their ADPs and provide good value for our teams this season. To see if this was the case, I pulled out some names I thought were interesting and dug into their profiles to see what I could find.
Marco Gonzales, Seattle Mariners
Marco Gonzales doesn't get enough love. For starters, he's only 28 years old and coming off 166 innings in 2018 and 203 innings in 2019. During a season when innings are going to be even harder to come by, Gonzales is a sneaky workhorse that everybody seems to overlook because he doesn't throw hard and he has a career strikeout rate of 19.2%.
Yes, Gonzales is never going to be a guy to miss tons of bats. Even in 2020 when he posted a career-high 23.1% strikeout rate, he had a 9th-percentile Whiff%, and his SwStr rate of 8.6% over the dates for this article put him 135th out of 168 eligible arms. Yet, he has above-average O-Swing% and Chase%, which suggests that he gets hitters to consistently swing at pitches that aren't strikes. While they don't miss those pitches - his Chase Contact% is 71.3% as a career, compared to the MLB average of 59.4% - he also keeps hitters off the barrel and consistently records a low HR/9.
So how does he do it? It's been the introduction of his sinker and complete abandonment of his four-seam fastball. Gonzales has almost doubled his sinker usage since 2018 and now throws the pitch 45.2% of the time. While it only gets a 7.9 SwStr%, it has a -13 Run Value, the second-best of any pitch in baseball last year, because it has a 23.9% called strike rate and limits hard contact. The reason behind that is simple in visual form.
Three of Gonzales' four pitches all have a Spin-Based movement within two hours of each other on the clock. That means they all come out of his hand and towards the batter at relatively the same place. The sinker, which has 99% active spin, comes in at 88 MPH with little deviation, while the cutter moves from 11:45 to 1:00 at 84 MPH, and the changeup, which also has 99% active spin, falls from 10:30 to 10:00 at 80 MPH. What that means is that, while the offerings may not have drastic movement (hence the low SwStr%), Gonzalez has three pitches that all move in opposite directions at different speeds while tunneling in the same way.
Even though he gets deception and limits hard contact with just those three offerings, his curve, which perfectly mirrors his sinker, had a called strike rate of 22.9% and a 32.5% CSW. He also seemed more confident using it with two strikes as became his best whiff pitch with a jump from 14.7% to 28.9%. In fact, Gonzales' deceptive pitch mix led to a rise in K% in 2020 on almost all his pitches. His sinker rose from 17.2% to 22.4%; his changeup went from 12% to 17.8%, and Even though his cutter stayed relatively the same, dropping from 24.5% to 23.9%, it suggests that the deception of his arsenal is potentially elevating the value of his offerings.
You're not drafting him for his K%, but most projections have him as a 4.30 ERA pitcher, which I think is crazy. He hasn't had an ERA that high since 2017, and his improvements since then have been noticeable and clearly connected to improved results. I see no reason why Gonzales isn't a sub-4.00 ERA arm again, and he's firmly in my top-50 starting pitchers for the year.
Ryan Yarbrough, Tampa Bay Rays
Yarbrough finds himself on the list thanks to the second-highest O-Swing% of qualified pitchers, trailing only Jacob deGrom, which is not something I expected to write. However, the left-hander accumulated a 12.4 SwStr% over the allotted time frame, while his induced Exit Velocity has been in the top 1% for the past two years. He pitched to a 3.56 ERA and 1.19 WHIP last year while also suppressing hard contact and keeping the ball in the park with his second straight season registering a HR/9 under one.
When looking at whether or not Yarbrough is actually deceptive, what stands out is a jump in Chase% from 32% to 37.5% in 2020 and a jump in Whiff% overall from 22.4% in 2019 to 27.7% in 2020. His O-Swing increased by 5.7% increase while his O-Contact% dropped 3.5%. With an identical Zone% and nearly identical Zone Swing%, it's clear that much of Yarbrough's deception came from improved success on pitches outside of the zone. But was that earned?
Much of his success with deception can be attributed to the increased use, and new shape, of his changeup. After throwing the pitch 25.6% of the time in 2019, he upped it to 30% in 2020 and also seemed to change the movement of the pitch, opting for more vertical drop and less horizontal movement. The pitch, which has an active spin rate of 95%, is a perfect complement to his cutter.
Although he delivers them from a similar release point, he throws the two pitches at opposite corners of the strike zone, keeping hitters off-balance.
His curveball, which he used increasingly as 2020 went on, mirrors his changeup perfectly, and, although used sparingly, had a 40.5% Whiff% and a .138 xBA and .185 xwOBA in part because of the way it plays off the changeup.
Yet, it might be Yarbrough's sinker, which is his best pitch by pVAL and Run Value, that is the key to the puzzle. The sinker has his highest called strike rate at 26.1% and induces weak contact with only a 3.3% barrel rate and -.4 degree launch angle. However, it also makes the changeup more effective based on the fact that it has a similar movement path to the change, but actually drops less and is nine MPH slower.
The similar observed movement is what causes the changeup to be such a strong whiff pitch for Yarbrough since he has hitters out in front, thinking about the sinker.
With three offerings designed to attack separate corners of the plate and a pitch mix centered around a perfectly paired cutter-sinker-change combination, Yarbrough's deception is more earned than flukey. Most projections peg him for an ERA around 4.30, but I don't see any reason why he can't put together another sub-4.00 season. He's never going to strike out a ton of batters, and likely won't break 8.0 K/9, but he will win games on a strong Rays squad and should be able to give you a 3.80 ERA and a 1.15 WHIP, which makes him well worth his 230 ADP when he should return better value than Tony Gonsolin, Zach Eflin, and Jordan Montgomery, who are all going about 40 picks earlier than him.
Alec Mills, Chicago Cubs
I know some people like Alec Mills, so I was excited to see his name on the list. At first glance, it made sense.
I mean, that all looks good. We have a sinker and four-seam that both start at 1:30 with the sinker having a -45 deviation, which changes enough to keep hitters off-balance. Then he pairs that with a changeup that starts at 2:00 and has the same -45 deviation as the sinker, only it's 10 MPH slower. Plus, he has a combination of breaking pitches in a slider and curve that mirror the fastball deliveries, with the slider also registering a -45 deviation, which mirrors the movement of the change/sinker perfectly.
The only problem is that Mills' pitch mix is a mess, and I'm not sure he or the Cubs know what type of pitcher they want him to be. The easy answer is to scrap the four-seamer. It's been either his worst or second-worst pitch each of the last two years. He tries to throw it up in the zone, but he only registers 7.28 Whiff% on it, and it gets clobbered to a .443 xSLG and .321 ISO. Mills seemed to understand this during the 2020 season and dropped his fastball in favor of the sinker, which has a 20.4% called strike rate during the dates used for this leaderboard, suggesting that it's a strong, deceptive pitch for him. But then, Mills' fastball usage jumped back up in September of last year as his most used pitch. Why?
If you look at the performance of Mills' pitches, you get a pretty clear picture of the one pitch that stands out from the others (courtesy of Brooks Baseball).
Scrapping the fastball would allow him to rely on the deception between the sinker and changeup combo while pairing that with a curve that has been a really good offering for him over the dates used for the leaderboard. It had a 25.1% called strike rate and 34.2% CSW, which is indicative of the way the speed of the pitch, which he throws at 67 MPH, is incredibly effective when it plays off his harder offerings.
From a spin direction and deception standpoint, it seems like a sinker, change, curve pitch mix would work best for Mills. He can then utilize his slider as his out pitch due to its impressive 16.2 SwStr% and 42.4 Whiff%. Yet, as of now, his pitch usage chart per start looks like a heart rate monitor with spikes and dips all over the place. I'll take Mills' position on this leaderboard and his overall repertoire as a sign that he has the ability to be a consistently deceptive pitcher, but I'm going to need to see him change his pitch mix in spring training to be interested in buying in.
Tyler Mahle, Cincinnati Reds
I loved me some Tyler Mahle last year. I mean, a .188 xBA, an 85th-percentile whiff rate, 77th-percentile xwOBA allowed, a 30% strikeout rate, and now a top-10 finish here over the last full season's worth of games. The key behind all of it seems to be the re-introduction of his slider. After throwing the pitch with no success in 2018, Mahle scrapped it in 2019 for a curveball that was marginally successful. However, Mahle wasn't missing bats, so he went back to the slider.
While it's important that Mahle got rid of his cutter, which got absolutely clobbered, the introduction of a new slider was equally, if not more, important to his jump forward. Possibly working with the Driveline guys now employed by the Reds, Mahle dialed back on some of the break he had on the 2018 version of the pitch. The pitch has only 28% active spin, but, because he throws it four MPH harder, it tunnels better with his fastball-splitter combination. As a result, the slider was Mahle's best pitch in 2020, registering a .179 xBA, .320 xSLG, with a 41.5 Whiff%, and an absurd 18.9 SwStr%.
It was also instrumental in making Mahle more deceptive overall. Although Mahle dropped his Zone % by 4%, the Zone Swing% against Mahle was a near-identical 64.7% and the Z-Contact% dropped 8% to 75.1%, which is below league average. His Chase% also increased 2% while his Chase Contact% plummeted from 61.5% to 49.6%. So, to sum that up, Mahle was throwing fewer pitches for strikes but getting more swings-and-misses in the zone and also inducing more swings on pitches outside the zone, and batters made way less contact on those offerings. All of that is great and likely attributed to his new pitch mix.
Now, the first thing to keep in mind is that the "changeup" mentioned here is really a splitter that Mahle throws at 87.5 MPH. You can see that, although it has the same trajectory as the fastball, beginning at 1:15, it actually drops down to 2:00 with near 14 inches of horizontal break.
Mahle is thus able to play the fastball and splitter off of one another against left-handed batters while using the fastball and slider to righties. The mix of his three main offerings not only allowed his overall Whiff% to increase 10%, but it dropped his Z-Contact% to an elite level of guys like Luis Castillo and Yu Darvish. As a result, Mahle has become a more deceptive pitcher, but, unlike some of the names on this list, one who does it by racking up strikeouts, not limiting hard contact. In fact, Mahle's fastball is the pitch that has the highest called strike rate at 20% (not including the 23% on the curve that he doesn't really use), so he's probably closer to guys on this list like Yu Darvish than he is the Marcon Gonzales'. I have him as my 42nd-ranked starter and think he could be good value, even at pick 160, which is in a dead man's land where only relievers seem to be getting taken (and also after Patrick Corbin, who I like less than Mahle).
Random Thoughts
There are some other names that are interesting on the top-20 list, but I didn't want to overload you with a lot of information, so here they are in quick blurb form:
Jose Berrios, Minnesota Twins
Because Berrios never turned into the elite strikeout pitcher many people were hoping for, the narrative is somehow that he is a good but not exciting fantasy option. He is currently the 26th pitcher off the board behind guys like Zach Plesac, Max Fried, Sonny Gray, and Stephen Strasburg, who had carpal tunnel surgery and may have issues gripping a baseball. I would take Berrios over all of them. The 25% strikeout rate is still solid, as is the 11.6% SwStr%, but he'll limit hard contact, keep a HR/FB rate around 1.15, and continue to be a solid mid-to-high 3.00 ERA arm in a weak division with a solid offense behind him.
Miles Mikolas, St. Louis Cardinals
The fact that Mikolas appears so high on this list, amidst some of the most talented pitchers in the game, is either a knock against this metric or a suggestion that we're all perhaps a bit too low on Mikolas. Here's the thing, even when he thought Mikolas was "awful" in 2019, he had a 4.16 ERA and 4.39 SIERA with a .302 BABIP. He also never had a feel for his slider, which was a 23.7 pVAL pitch in 2018. Remember that MLB changed the ball in 2019 and many pitchers struggled with the grip. The ball is allegedly new again this year, so if Mikolas gets the feel for that slider back in Spring Training, you may want to move him up your boards as a potential mid-to-high 3.00 ERA pitcher with an elite BB% who is currently going at pick 368.
Randy Dobnak, Minnesota Twins
As of this writing, Dobnak is still the fifth starter for the Twins. There's nothing special about him, but he limits barrel contact, rarely walks hitters, and induces a boatload of groundballs. That last part is important now that Andrelton Simmons will play behind him at shortstop. Dobnak's x-stats actually suggest that he got a bit unlucky with his sinker, and the sinker-slider-change combo creates a deceptive pitch mix that could make Dobnak a solid deep league target if you're looking for ratios and wins. He doesn't pitch super deep in games, however, so he loses some value in QS leagues.
Drew Smyly, Atlanta Braves
If I was going to write up a fifth arm, it would have been Smyly. His fastball velocity jumped by two MPH last year, and he upped the usage of his curveball, which was his best pitch with a .161 xBA, 50% whiff rate, and a 36 PutAway%. He found the zone more regularly, while his Zone Contact% dropped 4.3% and his Chase Contact% dropped a massive 25%. He's never been a consistent asset for innings, but Smyly could be a mid-to-high 3.00 ERA arm with a strikeout rate above 25%. That would be tremendous value considering projections have him as a 4.50 ERA arm with a sub 10 K/9.
Zack Greinke, Houston Astros
I love Greinke this year. In a season where innings may be hard to come by, I'll take the consistency of Greinke's 200 innings. Sure, he's 37, but his "down year" last year was partially fueled by a .321 BABIP. He had a 2.80 FIP and a 3.72 SIERA to go along with a K-BB% of 21.2% which is near the best of his career. I'll pounce on that security, especially if he's going to be drafted at pick 105, behind Dylan Bundy, Ian Anderson, Jesus Luzardo, and Dinelson Lamet (what are we doing?).
Kyle Hendricks, Chicago Cubs
Kyle Hendricks is the Rodney Dangerfield of Fantasy Baseball.
What more does this guy have to do? He's been an elite ratio asset for years, but over dates used for this leaderboard, he had a CSW over 34% on both his curve and slider. With David Ross as the manager, Kyle Hendricks was able to throw much deeper in games in 2020, pitching 81.1 innings across 12 starts or just under seven innings per start. I'm not sure why projection systems have him as a 188 inning pitcher, but you now get elite ratios across substantially more innings. He's inside my top-20, and I'd take him ahead of Corbin Burnes, Strasburg, Hyun Jun Ryu, and Zach Plesac, who is going 30 picks ahead of him.
Z-O% Swing Top-50 Leaderboard
Name | Team | Z-Swing% | O-Swing% | Z-O% |
Lance McCullers Jr. | Astros | 55.90% | 30.00% | 25.90% |
Aaron Nola | Phillies | 63.00% | 36.90% | 26.10% |
Zac Gallen | Diamondbacks | 60.40% | 33.90% | 26.50% |
Jose Berrios | Twins | 63.40% | 35.90% | 27.50% |
Stephen Strasburg | Nationals | 64.00% | 36.10% | 27.90% |
Miles Mikolas | Cardinals | 66.90% | 38.40% | 28.50% |
Dylan Bundy | Angels | 63.70% | 35.10% | 28.60% |
Brady Singer | Royals | 58.30% | 29.40% | 28.90% |
Tommy Milone | 66.90% | 37.70% | 29.20% | |
Ryan Yarbrough | Rays | 68.30% | 38.90% | 29.40% |
Yu Darvish | Cubs | 65.90% | 36.30% | 29.60% |
Zack Greinke | Astros | 62.40% | 32.30% | 30.10% |
Sonny Gray | Reds | 60.00% | 29.70% | 30.30% |
Marco Gonzales | Mariners | 65.60% | 35.10% | 30.50% |
Gio Gonzalez | 63.30% | 32.70% | 30.60% | |
Kyle Hendricks | Cubs | 67.70% | 36.90% | 30.80% |
Randy Dobnak | Twins | 66.50% | 35.60% | 30.90% |
Shane Bieber | Indians | 67.40% | 36.20% | 31.20% |
Zach Eflin | Phillies | 66.80% | 35.60% | 31.20% |
Jordan Zimmermann | Brewers | 65.60% | 34.30% | 31.30% |
Patrick Corbin | Nationals | 68.70% | 37.40% | 31.30% |
Mike Montgomery | 65.60% | 34.20% | 31.40% | |
Kyle Gibson | Rangers | 64.80% | 33.40% | 31.40% |
Ross Stripling | Blue Jays | 61.20% | 29.30% | 31.90% |
Gerrit Cole | Yankees | 66.50% | 34.50% | 32.00% |
Alex Cobb | Angels | 63.40% | 30.90% | 32.50% |
Alec Mills | Cubs | 65.30% | 32.70% | 32.60% |
Frankie Montas | Athletics | 63.20% | 30.40% | 32.80% |
Jason Vargas | 64.20% | 31.10% | 33.10% | |
Michael Pineda | Twins | 70.90% | 37.50% | 33.40% |
Blake Snell | Padres | 69.20% | 35.80% | 33.40% |
Dinelson Lamet | Padres | 65.40% | 31.90% | 33.50% |
Kenta Maeda | Twins | 70.50% | 36.90% | 33.60% |
Joe Musgrove | Padres | 69.20% | 35.50% | 33.70% |
Daniel Norris | Tigers | 67.90% | 34.20% | 33.70% |
Walker Buehler | Dodgers | 66.70% | 33.00% | 33.70% |
Tyler Mahle | Reds | 66.70% | 33.00% | 33.70% |
Drew Smyly | Braves | 66.10% | 32.40% | 33.70% |
Dallas Keuchel | White Sox | 66.70% | 32.90% | 33.80% |
Jose Urquidy | Astros | 66.60% | 32.80% | 33.80% |
Justin Verlander | Astros | 69.90% | 36.00% | 33.90% |
Clayton Kershaw | Dodgers | 68.60% | 34.60% | 34.00% |
Masahiro Tanaka | Japan | 72.10% | 38.00% | 34.10% |
Trevor Bauer | Dodgers | 66.20% | 32.10% | 34.10% |
Charlie Morton | Braves | 67.20% | 33.00% | 34.20% |
Steven Brault | Pirates | 65.20% | 31.00% | 34.20% |
Hyun-Jin Ryu | Blue Jays | 69.90% | 35.60% | 34.30% |
Dario Agrazal | 64.40% | 30.10% | 34.30% | |
Framber Valdez | Astros | 62.30% | 27.90% | 34.40% |
Adam Wainwright | Cardinals | 63.90% | 29.50% | 34.40% |
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