Swept

BY DEB SEYMOUR

Every baseball pitcher who continues to play the game beyond childhood develops an arsenal of pitches, whether it be a simple portfolio of just a fastball along with an off-speed pitch or a breaking pitch, or a more complex inventory of four or five different pitches thrown from distinct arm slots and with distinct hand grips.

Back in the earlier days of baseball, even at the major league level, if you had a really good knuckleball to accompany your fastball, that simple repertoire might have been sufficient to make you successful.

This major league season, following upon its introduction in 2022, we now have a pitch called the “sweeper,” along with some other new additions of which you may never have heard till this year. And the sweeper is all the rage, despite it being a variation on what we used to call a “slurve.”

With its now being given its own unique classification on Baseball Savant’s website, the sweeper becomes more open to analysis in terms of effectiveness and other aspects of its use in the league. Baseball Savant has separated the sweeper from the slurve as discrete pitch types, and so its data will follow suit.

And it’s already gotten quite a bit of media attention, because the pitch with which Team Japan player Shohei Ohtani struck out Team USA’s Mike Trout, his Angels teammate, for the final out in this March’s World Baseball Classic was a filthy sweeper. You could, in fact, say that Trout got swept.

Ohtani threw more sweepers than anyone in 2022. One of the early adopters of the pitch, Corey Kluber, now of the Red Sox, can make his sweeper look like a frisbee.

But what is the sweeper – and how does it, exactly, differ from the slurve?

For a true definition of the pitch, Dan Aucoin of Driveline (now with the Phillies doing R&D) outlines how Driveline classified sweepers in 2021: 77 mph, 6.5 inches of glove-side movement after 40 feet of ball flight, and -2 inches of depth after 40 feet of ball flight.

That’s a lot of measurement data, but what does that mean the pitch actually does?

The sweeper fits the vertical movement of the slider and shares the horizontal movement characteristics of curveballs and big sliders (simply, extra “sweep”). The velocity of the pitch rests in between sliders and curveballs as well: the 2022 league average sweeper was 80.2 mph, compared to 84.2 mph on sliders and 79.0 mph on curveballs. A great example of a pitcher who can demonstrate the differences between each pitch type is Chris Bassitt, now of the Blue Jays, who throws all three.

The sweeper is thrown slower than the slider, yet has some extra bite on it. But how is it different from the slurve?

Traditionally, calling a breaking pitch a slurve often meant that a pitcher struggled to distinguish their particular breaking ball from a curveball and a slider. The sweeper is a new version that’s actually intentional. While yes, the sweeper and the slurve do look similar, the sweeper is a development in pitch design that makes it out to be more than meets the eye.

The physics that make the sweeper unique are distinguishable in that the pitch moves more than the spin, velocity, and pitch grip suggest it would, as measured by StatCast cameras in major league ballparks. Because the extra movement is difficult to anticipate, the pitch is considered to be rather highly effective.

To get more technical, the extra movement is caused by changes in the Magnus effect of the baseball, which is the concept that the ball moves based on the pitcher’s grip on the ball and how their fingers apply pressure upon its release.

The spin on the ball creates a wake in the air as it cuts through the air, but it’s based upon how the motion of the ball began.

Now, you may wonder how the extra movement is so hard to anticipate by major league hitters who’ve been facing both good and bad pitching at all levels, while growing up and throughout their professional careers.

Well, because a baseball has lifted seams on it, it moves differently than, say, a softball, a golf ball, or a tennis ball, which each have their own movement characteristics. The lifted seams can create some irregular movement in flight.

The seams, when thrown in certain movement profiles, can create enough turbulence in the air that it can allow the ball to have free movement. This is known as the non-Magnus effect. Essentially, this means the ball can move in ways that can’t be anticipated by just watching the release.

There are other distinctly technical ways of describing what the sweeper does to throw off the hitter, some of which are shared by other non-fastball pitches, but the bottom line is it’s making its way into the league, along with some other more recently nicknamed pitches (the “slutter,” or slider-cutter, for example).

The sweeper had just a 2.3% usage in 2022, but all signs are pointing to an even bigger jump in 2023. Even though pitchers can seek out this development on their own during the offseason, teams like the Yankees and Dodgers have emphasized the sweeper movement in their systems.

The “Dodgers Slider” has recently become a trend that has seemingly revived the careers of Andrew Heaney and Tyler Anderson, while propelling guys like Evan Phillips and Julio Urías to new heights. Urias actually calls his pitch a slurve, making him one of only two pitchers to have thrown a slurve in 2022.

Similarly, the Yankees have molded their bullpen out of sweeper guys, which has allowed them to get significant value out of Clay Holmes, Michael King, Jonathan Loáisiga, and Clarke Schmidt. You may have heard the Yankees refer to the sweeper as a cutter of sorts, but their bullpen pitch essentially fits the definition of the sweeper.

The Yankees led the way in sweeper usage in 2022, while the Dodgers ranked fifth. The Angels, Red Sox, and Orioles ranked second, third, and fourth, respectively.

Among starting pitchers, Shohei Ohtani’s numbers in 2022 using the sweeper demonstrated among the highest effective use of the pitch, followed by those of Yu Darvish; while among relievers, Adam Ottavino and Colin McHugh ranked among the highest in effective use of the pitch.

With the incorporation of baseball development and improvement havens like Driveline and major league pitching laboratories into the game, you can expect to see further refinement of not just the sweeper (or the slutter), but other new pitching innovations in the coming years.

One caveat, however, is that given the newness of all these innovations, there is no long-term data on their impact on pitchers’ arms and career longevity. That all remains to be seen. In general, we don’t know yet whether pitches developed in laboratory environments impact pitchers’ arms and ability to throw deep into a career any more or less than pitches developed in someone’s backyard. Hence, regarding this aspect of the sweeper and the slutter and any other “newfangled” pitch, only time will tell.

*****

Data and descriptions sourced from:

Nate Schwartz, Pitcher List. March 29, 2023. See https://www.pitcherlist.com/a-sweeping-sensation-what-we-know-about-baseballs-hot-new-pitch/

Rob Friedman, @PitchingNinja, Twitter (April 6, 2023).