‘What was that?’ How a new pitch (or is it?) is making waves with the KC Royals
.jpg "KC Royals pitchers (left to right) Alec Marsh, Brady Singer and Seth Lugo all throw sweepers, a pitch that has made a recent resurgence in MLB.")
Kansas City Royals pitcher Alec Marsh had something new up his sleeve. For two weeks, he was crafting something so diabolical it left opposing hitters in awe.
If you blinked twice, you might not see it. This new thing moved with intention. Different variations lurked throughout Major League Baseball in recent years. Still, no one really knew what to call it.
This pitch has evolved into one of the most effective tools in a pitcher’s arsenal. And Marsh had the ability to harness it.
“Once I saw it move, I was like, ‘Oh, this is definitely going to be a weapon,’” Marsh said.
Last August, Marsh unleashed the pitch known as a sweeper. He used the pitch against the Boston Red Sox at Fenway Park. It was his eighth appearance and first as a bulk reliever.
Marsh entered in the fourth inning. He faced MLB veteran Adam Duvall, who is now with the Atlanta Braves.
Duvall saw three pitches in his at-bat, each in a different location. The first pitch registered as an 84.6 mph sweeper. It was center-cut and Duvall took it for a strike.
The second pitch registered 83.3 mph. This time the sweeper was on the inside part of the plate. Marsh got the strike call and left Duvall frozen again.
Marsh went back to it with the third offering. He threw an 83.9 mph sweeper that floated across the strike zone. Duvall nearly swung out of his shoes.
“You can tell he is walking back to the dugout like, ‘What was that?’” Marsh said. “Like, ‘We didn’t see that video.’”
Marsh, 25, had found his advantage. Last season, he registered a 45.0% whiff rate with his sweeper, per Baseball Savant. He limited opponents to a .222 batting average.
Put another way, he was making guys look silly chasing it.
The sweeper is not necessarily a new pitch — manager Matt Quatraro called it a “big slider” from 20 or 30 years ago mixed with a seam shift from about 4-5 years back — but its implementation in the Royals’ clubhouse offers a window into how the KC pitchers and coaches work together.
As spring training neared its end, around 10 pitchers in camp, Royals pitching coach Brian Sweeney said, were throwing the pitch.
It quickly became Marsh’s go-to. However, the sweeper is not for everyone.
Sweeping the nation
The sweeper is a fascinating construct. Depending on who you ask, there are different variations of the pitch.
Is it a slider or a curveball? What kind of grips work best with the sweeper?
“It’s like (taking) a curveball and putting it on its side,” Royals pitcher Jordan Lyles said.
Some players consider it a big slider with a gigantic shape. There is substantial horizontal break of around 10 to 15 inches. The sweeper stays on one plane as it darts to the plate. Hitters tend to swing under it as the baseball glides through the strike zone.
The sweeper is different from a traditional slider, curveball or even a slurve. Those pitches have a little more vertical break and more depth.
“You see the swing and miss on it, and guys are fooled by it often,” Royals reliever Dan Altavilla said. “If you can do it consistently, I think it’s a great pitch for guys.”
But not every pitcher can throw a sweeper. The goal is to control the baseball and get it to move as far left — for right-handed throwers — as possible. It’s good against same-side hitters as it avoids the barrel and forces plenty of swings and misses.
“I don’t throw a sweeper,” Altavilla said. “I know guys who do, but I don’t think the way that I throw kind of fits that mold. I did try it before. It just wasn’t comfortable for me.”
Pitchers that throw sweepers generally have supination bias. They are able to naturally add more spin to the baseball and tend to favor pitches with more horizontal break. The spin metrics work in conjunction with something called the “seam-shifted wake,” essentially how the baseball and its seams interact with the air during a pitch.
“If you are throwing it correctly, you use the seam effects to make that thing turn left or turn right,” Sweeney said.
The Royals have several pitchers who use the sweeper. Sweeney first saw former National League Cy Young winner Trevor Bauer throw it in 2018. Royals manager Matt Quatraro alluded to Tampa Bay Rays pitchers tinkering with the pitch in recent years.
Royals reliever Matt Sauer mentioned the New York Yankees actively teach the sweeper to a majority of their pitchers.
“The evolution of the pitch is kind of insane,” Sauer said.
Sauer was acquired by the Royals in the 2023 MLB Rule 5 Draft. While he doesn’t throw a sweeper, his hard slider does have some intricate elements.
“I throw a sweeper grip, but I throw it so hard it comes out more like a (traditional) slider,” Sauer said.
Others have quickly hopped on board.
‘Just had to see it once’
Sweeney came to Marsh with an idea last season. He had studied Marsh’s slider and felt it was inconsistent.
So, Sweeney proposed adding a sweeper to his arsenal. Marsh worked on the sweeper in bullpen sessions and while playing catch with other pitchers. It was a tough adjustment as he navigated his rookie campaign.
“I didn’t really start figuring it out until we got to Boston,” Marsh said. “I threw a bullpen and we switched the grip. We turned it into a knuckle-curve grip, almost just staying on the side of the ball. All of a sudden one caught. I just had to see it once to get confidence with it.”
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Still, Marsh had to replicate the pitch. There were times where he threw the sweeper in the dirt and relied on Royals captain Salvador Perez to block the baseball.
“I wore Salvy out one game with it,” Marsh said. “I kept yanking it and throwing it in the dirt. For a guy like him, I don’t want him to work that much.”
Marsh can laugh about it now. He still talks with Perez about that game. Perez just smiled as he chalked it up to growing pains.
“He was learning,” Perez said. “When you don’t know how to do one thing, the first times are not going to be as good as you think. You have to try to keep working. I saw the game the other day (in spring training), his sweeper looked pretty good.”
The Royals had multiple pitchers throw sweepers this spring. The group includes veterans Seth Lugo, Brady Singer and Lyles, the last of whom tried a sweeper for the first time after an analytics staff member in Texas suggested it to him in 2021.
“This is probably going to be the next kind of hot thing,” Lyles recalled that Rangers staff member telling him.
Sweeney said the Royals have a holistic approach to teaching the sweeper. The pitching coaches look at a pitcher’s delivery and plot how their pitches move and break.
Marsh had the characteristics to learn the sweeper. Sweeney wondered if Singer could also add it to his arsenal. He thought it would help Singer balance his sinker, slider and changeup.
So, Sweeney set up a PowerPoint presentation and proposed it.
“I know I wanted to throw one, as that was something me, Sweeney and (Royals assistant pitching coach Zach) Bove talked about during the season,” Singer said. “I wanted to learn some grips from them and was able to repeat it.”
Singer tossed 14 sweepers late last season. This offseason, he worked out with other MLB pitchers in Tampa, Florida. He was able to learn more about the sweeper and got advice on how to effectively throw the pitch.
The group included San Diego Padres pitcher Michael King and Chicago White Sox pitcher Jake Woodford.
“We just had a good group of guys that were kind of throwing the sweeper more,” Singer said. “We were kind of bouncing ideas off each other. All those guys threw that pitch. I learned the grip, kind of a split-sweeper grip, and the metrics on it. Just trying to refine it a little bit more.”
That splitter grip creates a gap between Singer’s fingers and allows him to apply more pressure on the baseball. In turn, Singer has more control to generate spin on the pitch.
“He’s got more weapons to bring to the fight,” Sweeney said. “He was basically a two-pitch pitcher down in the (strike) zone. Now he is using all the quadrants. He is east and west, north and south. Way easier way to build outs.”
‘Taking a left turn’
Lugo learned the sweeper before signing with Royals. So he already understood the impact it can have for a pitching staff.
It’s why he picked it up from former Padres teammate Rich Hill last season.
“He wasn’t throwing it but was trying to,” Lugo said. “So, I just decided to try a couple two-seam curveballs. And then I picked it up. I could see the very first ones I threw taking a left turn. I didn’t consider it a sweeper. I considered it a different variation of my curveball. But, according to the metrics, it was a sweeper.”
And Lugo saw an increase in his metrics. The sweeper registered a significant horizontal break and had the desired movement. It opened avenues for his other pitches.
Controlling it was another story. Lugo said he threw the sweeper to the backstop a couple times in bullpen sessions.
“I think I might’ve strained a guy’s oblique reaching over there,” Lugo joked. “It’s really cool to see that kind of action. Once we got into the game and started seeing the hitters’ reactions, that’s when we really started to make some adjustments.”
Lugo’s change: He started taking velocity off the sweeper and allowed it to move through the strike zone. He threw it like a lazy breaking ball. It was far better than blasting it, and he eventually could repeat the movement.
Now, Lugo is not afraid to use the sweeper in any count.
“I guess since it’s become such a big pitch in the league, I kind of watched what other guys are doing with it,” Lugo said. “I actually think back to about 10 years ago, you see these guys throwing wipeout sliders: They are sweepers. So it kind of makes sense now.”
‘Oh my God, it works’
Pitchers continue to find ways to improve. The sweeper is now at the forefront of the latest innovation wave.
The different grip variations and spin metrics make the sweeper unique. Singer added the sweeper and a four-seam fastball to his arsenal. He has shined in spring training with more tools at his disposal.
Marsh took the next step after adding it to his repertoire. He was recently named the Royals’ fifth starter for the 2024 season.
“Really unique story for Alec,” Sweeney said. “It goes to show you can develop at the major-league level and guys want to get better. And we want to support that.”
Hitters now have to prepare for something else. Royals star Bobby Witt Jr. expects to see the sweeper more moving forward. There will be an adjustment but one that will require hitters to stay back and remain patient at the plate.
“I think it’s the same pitch that everyone has been throwing, it’s just a new name,” Witt said.
As hitters adjust, pitchers must continue refining the sweeper. For now, it’s still an effective pitch that leaves most hitters searching for answers.
With the occasional awe moment when a pitcher figures out how to control it.
“It was a cool feeling,” Marsh recalled of his first successful sweepers. “It was like, ‘Oh my God, it works.’”
