Raising Aces: Diff’rent Strikes

The Minnesota Twins have earned a reputation over the years for their general preference toward “strike-throwing” pitchers who are adept at avoiding free passes, and the recent signings of Ricky Nolasco and Phil Hughes only reinforce that idea. Nolasco has maintained a walk rate between 4.8 and 5.7 percent in each of the past six seasons, and Hughes has kept his at six percent over the past two seasons combined. Both pitchers have been vulnerable to hard contact, manifested in higher-than-average rates of hits and homers allowed, and the combination of box-score stats paints the picture that they spend a lot of time within the strike zone. But does the PITCHf/x data support that notion?

It might surprise some readers to learn that both Nolasco and Hughes throw the majority of their pitches outside the strike zone. Just 42.6 percent of the pitches that Hughes has thrown over the past two seasons have crossed the plate within the confines of the zone, a number that might feel intuitively low but is actually above the league average. Nolasco's in-zone rate is even lower, and sunk to a career-low of 38.2 percent in 2013.

When comparing walk rates to these ratios of pitches within the strike zone, certain caveats emerge with respect to command versus control as well as the fact that a decent chunk of pitches are targeted outside the zone, particularly in the case of secondary offerings that are designed to be buried below the hard deck. That said, there are some trends that emerge when one digs deeper into the PITCHf/x data, with the prevailing theme that all strikes are not created equal.

I went through the numbers on www.BrooksBaseball.net, as well as those available on the PITCHf/x leaderboards here at Baseball Prospectus (also provided by Brooks Baseball), specifically targeting the high-end outliers with respect to manipulating the strike zone. Though not every elite pitcher fit neatly into a defined category, there were a handful of archetypes that did emerge.

(All statistics are for the 2013 season only. A minimum of 2000 pitches thrown was necessary for inclusion).

IZ% is the percent of all pitches thrown that registered within the strike zone
W/S% is the percentage of whiffs divided by swings
IZW% is the whiff percentage for pitches within the strike zone
OZW% is the whiff percentage for pitches outside the strike zone

Chasers

Our first group of strike-inducers includes those pitchers who rely on batters to chase their offerings that dart, duck, dip, dive, and dodge out of the strike zone. Liriano is the poster-boy for this approach, as he throws pitches over the plate less than one-third of the time, and yet his rate of whiffs on those out-of-zone offerings is an exceedingly high mark of 16.32 percent. The lefty had a banner year in 2013 largely due to his ability to bury the slider under the zone and provoke batters into chasing, though his lack of mechanical repetition leaves one to wonder whether he can repeat that success next season.

The changeup is the key to King Felix's success, with a 41.8-percent rate of whiffs-per-swing when el cambio comes out to play. The pitch has tremendous depth as well as arm-side run, coaxing batters to swing regardless of the pitch's destination. Lincecum also relies on the off-speed pitch as his weapon of choice when a whiff is in order, and his success is often dictated by whether he can effectively bury the pitch throughout an at-bat.

If one wishes to watch the best hitters in the world take child-like hacks at baseballs, then Darvish presents the best opportunity for a show whenever he takes the mound. He is the ultimate source of batter frustration, with a plethora of offerings that can invoke whiffs due to exaggerated movement in both the lateral and vertical directions. His whiff-per-swing rate of 31.5 percent was the highest in baseball in 2013, and the preponderance of flailing swings gives Darvish less incentive to hand opposing batters something within the confines of the strike zone.

Danger Zone

There is perhaps nothing more impressive than a pitcher who can generate empty swings within the strike zone. The pitcher is essentially challenging the hitter to make contact with a pitch that is within reach, and yet the velocity, movement, and/or sequence-dependent deception of the pitch is enough to fool batters into taking swings that are mistimed, misplaced, or both. This group of pitchers not only registered in-zone whiffs at the highest frequencies in the league, but they also demonstrated the ability to entice higher rates of empty swings inside the strike zone than outside of it.

Scherzer had the highest in-zone whiff percentage in baseball at nearly 15 percent of pitches thrown. The slider was his deadliest pitch overall, even when thrown over the plate, leading to a whiff rate above 19 percent in the zone. One might expect such results from breaking pitches, but Scherzer's fastball was potent in the strike zone as well, triggering a greater than 15-percent frequency of empty swings last season.

The seasons of Teheran and Miller had vastly different shapes, with Miller bursting out of the gate before slowing down the stretch, and Teheran coming on strong as the season progressed. Yet their strategic approaches to owning the strike zone produced similar results, and such dominant displays on pitches within the zone are rare for young pitchers. Miller was also an instigator of foul balls, with many of his strikes ending up out of play; he had the second-highest rate of fouls-per-swing in the majors last season. Greinke and Verlander were apparently classmates in Strike Zone Management 101, with each right-hander having a relatively low percentage of pitches that ends up in the strike zone yet very similar whiff results regardless of pitch location.

Equal Opportunity Whiffers

This group contains some of the game's great strikeout artists, whose whiff-generation skills cross the barriers of the strike zone. Matt Harvey registered the third-highest strikeout percentage among 2013 pitchers who qualified for the ERA title, and though his season was cut short by a busted UCL in his throwing elbow, the future is bright so long as his command survives the trip under the knife. His combined-zone whiff rate (IZW% + OZW%) was the highest in baseball, surpassing Scherzer’s and Darvish’s, and his whiffs-per-swing ranked fifth in the game. Each arrow in his four-pitch quiver is tipped with poison, paralyzing batters with whiff-per-swing rates between 24 and 36 percent.

Sanchez enjoyed a breakout season in 2013, particularly on the whiff scale. His impressive rates were driven primarily by his changeup and slider, which led to the third-ranked whiff-per-swing frequency in baseball. The trio of NL lefties that follow Sanchez on the list feature widely disparate approaches from the standpoint of stuff, yet each features an exceptional device for missing bats—Hamels carries a deadly change, Bumgarner has the fade-away slider, and Kershaw owns a destructive duo of breaking pitches that gives batters nightmares.

Painters

This list includes pitchers who not only find the zone but hit targets with ultimate precision. As a general rule, the majority of pitches that find the strike zone invoke swings from opposing hitters, resulting in the phenomenon that no pitcher in the majors generates more called strikes than balls, but Cliff Lee comes the closest among pitchers who threw more than 2000 pitches in 2013. His frequency of 0.74 strike-to-ball calls is the highest such ratio in the game, and his 47.2-percent rate of pitches thrown in the zone is by far the highest mark of the pitchers under investigation.

Zimmermann is also adept at hitting targets within the zone, but rather than coax strike-calls from umpires, Zimm specializes in generating weak contact early in the count. He has been vocal about this intent, choosing pitch-count efficiency over gaudy strikeout totals, and the impact of that approach can be seen in his 49.1-percent rate of swings on all pitches thrown (fourth highest in baseball), combined with the modest percentage of whiffs-per-swing.

Price doesn't have the same reputation as Zimmermann, but the results featured even fewer empty swings last season. Price's whiff-per-swing rate dropped three percentage points from 2012, yet even during his Cy Young campaign the Rays' southpaw had a relatively modest pace of whiffs when compared to his competitors for the hardware. What he does is coax strike-calls from umpires (with a tip of the cap to framing mastermind Jose Molina), and Price had the third-best ratio of strike-to-ball calls in baseball last season. Lee and Price are particularly effective at using the full arsenal to hit targets within the strike zone, especially early in the count, often saving their whiff-inducing secondaries for two-strike counts.

Category 5 – The Perfect Storm

The pitchers in this cohort don't fit comfortably into any one of the previous categories, yet they possess the across-the-board profiles to approach inclusion for multiple groups. Sale falls just short of the in-zone percentage necessary to earn his own paint brush, despite the fact that his called strike-to-ball rate was the fourth-best in the league. Yet his whiff rates are better than the painters’, and though his swing-and-miss rate within the strike zone falls 0.39 percent short of the double-digits necessary for equal-opportunity status, the fact remains that his whiffs-per-swing can hang right in there with fellow lefties Kershaw, Hamels, and Bumgarner. It all adds up to a stellar profile that deserves its own category, in which Sale is not alone.

Strasburg has a very similar profile to Sale, though his statistical resume from 2013 is just a tad weaker in almost every category. The numbers from 2012 are very similar to '13 for Stras, though he did cross the double-digits necessary to be considered for an equal-opportunity gig. The combined line for Iwakuma also draws Sale comps, particularly in the categories of pitches thrown over the plate as well as whiffs outside the zone. Iwakuma's success is driven by his trap-door splitter that pulls the string on hitters below the shelf.

Fernandez is a particularly unique specimen. He technically qualifies for the painter's union due to his exceptional ability to locate both the fastball and the Defector within the strike zone, but his notable skills in generating empty swings sets him apart. His overall whiff-per-swing percentage would stand out among that group, as would his rates of whiffs both in and out of the zone, but those numbers are a good fit for Category Five. He also proved superior to his groupmates in finishing hitters with two strikes; Fernandez had a “Put Away” rate of 27.9 percent, which indicates his success in earning the K on two-strike pitches, and the rookie's score was good enough for the fifth-highest mark in baseball (among qualifiers).

Fernandez almost deserves his own category given the uncommon profile, but there is one pitcher who is truly in his own class.

A & W

Wainwright is a borderline chaser, with his sub-40-percent in-zone rate as well as the large disparity in whiffs, given that he leans so heavily on empty swings with his secondary pitches that are buried under the strike zone. But A & W had a much lower frequency of whiffs than the other chasers; he also ranked seventh in all of baseball in ratio of strike-to-ball calls, outlining his ability to drop curves over the plate as well as paint corners with his cutter.

In this exercise of classifying pitchers based on strike-inducing habits, Wainwright lacks a worthy contemporary.