There’s a new fixture at ballparks this year, besides the pitch clock and bigger bases. This one did not have its own marketing campaign, and it wasn’t tested with focus groups and minor leaguers. Even those responsible for it have been startled by its presence on stadium scoreboards.

“When it said ‘sweeper,’ we were like, ‘What the heck?’” said Michael King, a Yankees right-handed reliever. “We had no idea. But I think it’s just a different way to classify a pitch, because there’s so many different sliders out there.”

Major League Baseball’s Statcast system, which feeds information to scoreboards and television screens, has quietly introduced the sweeper and the slurve as new pitch types this season. The slurve is well known, though, as a combination of a slider and a curve. A sweeper is … what, exactly?

“It’s kind of a glitch pitch,” said Matt Blake, the Yankees’ pitching coach. “Some guys were throwing it, but maybe didn’t really understand how they were doing it. And then as information came out, all of a sudden more people were starting to look at it and saying, ‘OK, I can take it to this guy or that guy,’ and now all of a sudden everybody’s got it.”

Specifically, a whole lot of Yankees throw it. While Blake said the trend began with the Houston and Cleveland staffs around 2017, the Yankees have eagerly preached the virtues of the sweeper throughout their system.

King, Nestor Cortes, Clay Holmes, Ron Marinaccio and Clarke Schmidt all throw it. So do a few pitchers traded last summer who were nurtured in the Yankees’ system, including J.P. Sears and Ken Waldichuk of the Oakland Athletics and Hayden Wesneski of the Chicago Cubs.

“It’s an opportunity to say, ‘OK, what’s their primary breaking ball, and does it get swing-and-miss?’” Blake said. “Maybe we have an opportunity to add something here — try this.”

The sweeper is a horizontal slider, Blake said, with less downward movement than a slurve. A classic slider, like Gerrit Cole’s — often referred to by the Yankees as a “gyro” slider — is meant to look like a fastball to the hitter, who then swings over it when it breaks downward. The sweeper never looks like a fastball, but baits the hitter by seeming like a hittable breaking ball before darting away from the bat.

“You want side-spin,” said King, who learned his sweeper from the former Yankees starter Corey Kluber, who is now with the Boston Red Sox. “We always talk about the nose of the ball, and if you’re throwing a gyro slider, the nose is pointed straight at the hitter, like a spinning red dot. With the sweeper, you want the nose up.”

Pitching is a brotherhood; teammates and even opponents routinely compare grips and share tips on finger pressure, seam orientation and so on. Now that high-speed cameras are a common teaching tool, pitch design is more precise and efficient, and teams devote more resources to it — in technology and manpower — than ever. The right breaking ball can turn a fringe prospect into a big leaguer.

Often, of course, data only popularizes what older generations already knew. Before it had a name, the sweeper helped fuel the Yankees’ dynasty in the 1990s and early 2000s through David Cone, a top starter, and Jeff Nelson, a standout setup man.

“A right-hander can start it at the hitter and break it over the inside corner for a front-door sweeper — I’d start that right at their hip,” Cone, now a television analyst, said in the YES Network booth before a game last week. “That pitch was kind of frowned on by old-school pitching coaches, because a mistake is a home run: off-speed and on the inner part of the plate, if hitters recognize it, they can launch it and pull a fly ball.”

He added: “But it’s about shape. A sweeper’s got that bigger, flatter break, and designed for a swing-and-a-miss or a flinch. If it’s front-door, it’s to get the guy to flinch. When you’re throwing it away, it’s to get them to swing and miss.”

Nelson, who now calls games for the Yankees and the Miami Marlins, said he always considered his signature pitch a slurve — “a hard, big-breaking slider,” he explained. Nelson, a 6-foot-8 right-hander, threw from a low three-quarters angle and used a riding, inside fastball to keep right-handed batters from reaching his sweeping breaking ball.

“Sometimes there was so much of a break, you’d try slowing it down and it still broke a mile,” Nelson said. “Some days it was like, ‘I don’t know how to control this thing.’”

Nelson indeed could be wild, but he routinely had more strikeouts than innings pitched, before that was common for relievers. Closer Mariano Rivera’s celebrated cutter got plenty of swinging strikes but was more famous for breaking bats — the ultimate result of weak contact. The cutter looks like a fastball before a late, lateral slice; Cone calls that pitch a “baby sweeper.”

The Yankees’ current closer, the right-handed Holmes, has an exceptional sinker that runs in on right-handed hitters. He complements it with both a slider and a sweeper, and said it makes sense to differentiate the pitches.

“Last year I threw both, but if you went on Statcast, it was all just one pitch,” Holmes said. “I was throwing a sweeper and a gyro but it had them as one, so the average was not indicative of either pitch, really — velocity, movement, anything. It was a blend of both, so the average wasn’t really showing this pitch shape and that pitch shape.”

Now, this shape and that shape have official names of their own.