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Welcome back to Rotoballer's series using Statcast to extrapolate, dig into, and commiserate over data to examine pitching performances. The weekly series will be dynamic as we fine-tune our findings and enlighten ourselves on the information and tools at our disposal.
For the first two months of the season, the baseball community has fixated on the alarming increase in strikeouts. Through May 29, the average team's strikeout-to-hit ratio (K/H) is 1.03, an +8% increase compared to the entirety of 2017 (0.95). Although that may not seem shocking, there has never been an MLB season where strikeouts exceeded hits. This has a trickle-down effect on pitcher usage and our related fantasy assets; more strikeouts, more pitches thrown, fewer innings pitched, less emphasis on starters, you get the point.
Today we focus on the importance of strikeouts for fantasy pitchers. The metric we'll stress is O-Swings-and-Misses (O-SM%). O-Swing% is defined by Fangraphs as pitches outside the zone plus swings at pitches outside the zone. We'll take it a step farther and look only at swinging strikes, ignoring other results outside the zone. The argument is pitchers that get more chases outside of the strike zone have better odds of maintaining their K/9, increasing their season-long fantasy value. For reference, the median O-SM% is 5.3%. Comparatively, the median Zone-swings-and-misses (Z-SM%) is 4.7%.
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Whiff Wizards
All stats as of May 29 for 112 qualified pitchers with over 750 pitches thrown
Patrick Corbin, Arizona Diamondbacks (5-1, 2.47 ERA, 0.89 WHIP, 11.42 K/9)
We discussed the prowess of Patrick Corbin a couple weeks ago in our topic on early-inning slugging percentage. A possible reason Corbin has been so effective in retiring batters is he leads the majors with a 9.4% O-SM%. Pair this with an above average Z-SM% of 5.0% and the outcomes are justified.
Corbin's current K/9 is up a full +35% on last year's 8.45 clip, so it's safe to say his strikeouts haven't been dependent on league trends. Corbin peeled back on his four-seamer and upped his sinker usage to 32%. The average velocity on both pitches are nearly identical, except Corbin gets 8.7 inches of horizontal movement on the sinker compared to less than five inches for his fastball. The resulting effect has been strong pitch values on both pitches that have been historically poor for Corbin. Combine that with his bread-and-butter slider and Corbin's become a legitimate strikeout guru.
The risks with Corbin remain unchanged. He's gone seven-plus innings only thrice in 10 games and his .232 BABIP blatantly contradicts a 40.9% Hard%. He's sixth in the league in LOB% (85.5%), but that could certainly be a perk of the strikeouts. There's also been recent murmur about the dip in his fastball velocity which he's gradually deemphasized. His 3.03 FIP and 2.69 xFIP suggests Corbin's been no fluke through two months. Enjoy the strikeouts, and let the breakout unfold.
Trevor Bauer, Cleveland Indians (4-3, 2.61 ERA, 1.13 WHIP, 10.70 K/9)
In the offseason, we used Trevor Bauer as an example of how more first-pitch strikes could lead to higher strikeouts overall. Compared to 2017, Bauer has increased his F-Strike% from 56.9% to 61.5%. Correspondingly, the K/9 has ticked up slightly from last year's personal best 10.0. Well done, Trevor.
Bauer is 10th in the majors with a 7.6% O-SM% and also enjoys a decent 5.0% Z-SM%. He's carried over last year's second-half success and continues emphasizing a very effective slider, generating an excellent whiff percentage near 20%. Bauer's 6.4 wSL pitch value is good for eighth-best in baseball. Since pitches in a plate appearance are interdependent, it's no wonder the values for his remaining arsenal are also better.
Since Bauer's K/9 hasn't upgraded as materially as Corbin's, it's fair to nitpick. His BB/9 hasn't budged from last year (3.11) and he's been extra lucky with the long ball (0.50 HR/FB). However, a lot more seems real than luck. The BABIP (.291), LOB% (77.1%) and batted-ball distribution seem in-line with prevailing trends and aren't a concern. There was significant hype on Bauer's revelation last season and his embracing of analytics. The dividends thus far in 2018 look to be bearing fruit.
Other strikeout contenders: Kenta Maeda (LAD, 8.0% O-SM%), Dylan Bundy (BAL, 7.3%), Luis Castillo (CIN, 7.1%)
Swing and No Miss
Trevor Williams, Pittsburgh Pirates (5-3, 3.43 ERA, 1.13 WHIP, 6.14 K/9)
Trevor Williams is another familiar name in our series. We contemplated his impending downfall in Week 6 when we deemed his two-strike batting average too fortunate. Another fly in the ointment was the meager K/9 that no longer holds water in today's game. Williams currently has the fourth-lowest O-SM% at 3.0%. Combine that with an unremarkable 4.3% Z-SM% and he remains a tough buy.
The issue with Williams isn't just the low strikeouts, but that he also lives outside the zone (41.5% Zone%). Inducing soft contact and putting balls in play is fine, but having issues with getting batters to chase and refusing to challenge them doesn't do any good. Williams' repertoire predominantly relies on a fastball and sinker and neither have been great nor overpowering. Although the walks have improved, he still owns an inefficient 2.15 K/BB.
In fairness to Williams, his previously disturbing peripheral metrics have somewhat normalized. Along with fewer free passes, his BABIP (.243) and HR/FB (9.5%) have climbed to more appropriate levels. He's even raised the K/9 closer to last season's 7.0 mark. There's no doubt Williams may be serviceable during the year, but at best he's a start-to-start streamer. His FIP still sits stubbornly at 4.19 (4.64 xFIP), and the swing and miss data simply doesn't validate a long-term roster spot on fantasy teams.
Tyler Chatwood, Chicago Cubs (3-4, 4.10 ERA, 1.76 WHIP, 8.19 K/9)
Finally, a new name to deliberate. Tyler Chatwood's been awful. Even as we consider the respectable K/9, it's incredible that his K/BB is a ghastly 0.98. That figure is easily worst in the majors. Unsurprisingly, Chatwood's 3.8% O-SM% 15th-lowest in the majors. Possibly less encouraging is his 3.3% Z-SM%. Hitting the strike zone and producing contact is not an ideal combination.
There was a time in Chatwood's career he was better at inducing swinging strikes. Compared to 2017, the whiff rates for his four primary pitches (fastball, sinker, slider, curveball) have declined. It's difficult to pinpoint the deterioration, but velocity is down across the board. He's also lost some vertical movement in his sinker, which he utilizes almost 33% of the time. Another factor could be the blatant wildness, which has likely prevented him from throwing "his pitch" on demand.
Chatwood's K/9 this year is currently the highest in his seven-year career. But the dilution from the walks makes that contra-argument almost meaningless. Chatwood's WHIP has crushed his in-game durability and fantasy value. He's lasted less than five innings in four of nine starts. Until he rediscovers the strike zone, Chatwood is impossible to trust. His ownership level is egregiously higher than other K/BB cellar dwellers like Ty Blach, Sal Romano and James Shields. Come on, fantasy owners, you're better than that.
Other strikeout pretenders: David Price (BOS, 3.0% O-SM%, Jake Arrieta (PHI, 3.2%), Brandon McCarthy (ATL, 3.2%)
