Why MLB pitchers grunt when throwing a pitch

Baseball’s charm comes in many forms, including through the sounds of a game-day atmosphere. The crack of the bat, an organist’s rendition of “Take Me Out to the Ball Game,” synchronized cheers from the crowd.

And sometimes, the bellow of a grunt coming from the guy on the mound.

Though most commonly associated with tennis, grunting has long been a part of baseball. From Nolan Ryan in his heyday, to the brown- and blue-eyed Max Scherzer, a number of pitchers have utilized grunting as a tool for success.

Numerous studies suggest that tennis players who grunt gain velocity on their swing, especially on a serve. Though research is more limited on the baseball side, a study conducted by Hardin Simmons University in 2021 concluded that “mean ball velocities with a maximal grunt averaged 2.73 mph faster than ball velocities without a grunt. Results were statistically significant showing an average increase of 3.4% in throwing velocities while grunting.”

An internal tool to increase velocity was probably the last thing hitters facing the flamethrowing Ryan wanted.

While Monica Seles, Jimmy Connors and John McEnroe are credited with bringing the grunt to tennis, Ryan pioneered the grunt game in baseball from the outset of his 27-year career. Much like tennis players reach for the grunt in a particular part of their game (usually on the serve), Ryan — who threw a fastball, curveball and changeup — only vocalized on his maximum-effort pitch.

“Maybe they do it by design, I don’t know. But I certainly didn’t,” said Ryan, who debuted with the Mets in 1966. “I think it just developed. I didn’t do it on purpose. I think the fact that I was what I call a ‘maximum-effort guy’ on my fastball, that [grunting] was just a response.”

Ryan described his now-famous grunt as a “natural reaction” to the effort his body put into throwing his fastball. That reaction was a part of Ryan’s career for as long as the Hall of Famer can remember. As it did for Ryan, grunting emerged from the subconscious of other pitchers, but wasn’t always part of their game.

Blue Jays reliever Jordan Romano first noticed his grunt sometime between 2022-23, four years into his Major League career. Romano, a former teammate of grunt-extraordinaire Robbie Ray, said he thinks being around Ray partially influenced his adoption of the grunt.

“Maybe hearing him just allowed me the freedom to do it myself as well,” Romano said. “I’m not sure exactly how it started. But it just kind of progressed, and now we’re just doing it every time. And I like it.”

As a pitcher with a two-pitch mix who described himself as “max effort, all the time,” Romano said withholding his grunt would inevitably hinder his performance.

“I’m giving it everything I got, so the grunt is kind of natural,” Romano said. “Some people are a little more calm on the mound, calm and collected, whereas I am not. So the grunt just kind of makes sense for me.”

For other pitchers, grunting is a calculated decision. A 17-year MLB veteran who now pitches for the Rangers, Scherzer said he’s grunted for as long as he can remember. Scherzer is aware that he didn’t earn his “Mad Max” nickname as a result of being calm and collected on the mound. But don’t be fooled, his demeanor is well thought out.

“I say, ‘you pitch with emotions, but you don’t want to be emotional,’” Scherzer said. “I sometimes wear my emotions on my sleeve and use it to my advantage. I like to think I’m a high-adrenaline pitcher: I like when you’re in those situations where you’re competing at your highest and it takes everything you’ve got in order to get somebody out.

“When you’re locked in, you can throw the ball as hard as you can and locate it, you can get it into the area. And that’s when you know you’re synced up, is when you can throw the ball as hard as you can and you hit your spot.”

The ability to locate a spot is perhaps evidence behind why more veteran players than new big leaguers embrace grunting. With experience comes an ability to gauge how much effort you need to exert in order to land your pitch. Scherzer described honing the ability to grunt as a process of gaining confidence. Master the art of command, and then use that trust in yourself to increasingly pitch with more effort.

Aside from their grunting, Ryan, Ray, Romano and Scherzer have something else in common: They throw hard.

Enter the grunting outlier.

Compared to Romano’s 96-97 mph heaters, or Scherzer’s mid-90’s arsenal, Rich Hill has found success as a lower-velocity pitcher. Primarily throwing a curveball and four-seamer, Hill’s highest career average velocity came in at 88.5 mph in 2022.

“It definitely gives you a bit more conviction behind the pitch,” Hill said. “Over time it’s not like, ‘OK, the louder the grunt, the better the pitch.’ It’s just like, I know my effort level is there. And you know when it’s fake and when it’s not.”

Now known for his vocals, Hill didn’t start grunting until roughly 10 years into his Major League tenure. Across six organizations, Hill pitched in 201 games (74 starts) from 2005-15.

Wanting to return to a starter role, Hill caught the eye of the Red Sox (for the second time) in 2015, signing a Minor League deal and earning a September callup. Hill made four starts for Boston, pitching to a 1.55 ERA before signing a one-year deal with the A’s in the offseason.

Pitching for Oakland and the Dodgers in 2016 and newly equipped with a grunt, Hill recorded a 2.12 ERA over his most starts (20) since his ‘07 season with the Cubs (32). While Hill doesn’t solely attribute his career resurgence to the addition of a grunt, the vocalization represented a longer-term evolution and maturation that helped him own who he was as a pitcher.

“It was a little bit of a change in my personality as well out on the mound,” Hill said. “I became more comfortable with understanding who I was as a pitcher. And I think that’s something that showed itself and its personality when I went out there on the mound.”

Hill grew up a tennis fan, noting that he was locked in on players like Andre Agassi, Connors and Pete Sampras — especially surrounding Grand Slam events. Rather than be inspired by his idols on the tennis court or influenced by a vocal teammate, Hill’s journey to grunting looked more like a stumble.

“I just kinda said, ‘Screw it,’” Hill said. “Whatever I have to do to go out there and have the ball come out of my hand the way I want to with that intensity at the finish of my pitch. And if it includes that grunt, then it includes the grunt.”

Now 44 years old, Hill signed a Minor League contract with the Red Sox in mid-August and was selected to the Major League roster on Tuesday, marking his fourth stint with Boston. Nearly 10 years after experimenting with the grunt and leaning into his personality on the mound, Hill rejoins the organization with a 3.72 ERA over 181 games (174 starts) since 2016.

“[The 2015 season] was another opportunity and I was like, ‘I’m going to put the pedal down to the floor and I’m not gonna take it off until the ball gets taken out of my hand,’” Hill said. “So whatever that looks like, and however pretty it is, however ugly it is, that’s what you’re gonna get. There were no apologies for it either. I think that getting to that point in your career where you’re unapologetic about your performance, I think it’s extremely freeing.”

While the numbers don’t universally support that grunting adds velocity, the consensus among veteran pitchers seems to be that grunting offers a way to dial up intensity and leave it all on the mound. And that unabashed almost primal behavior is something that pitching coaches have embraced, including the Blue Jays’ Pete Walker.

“I think it’s more than just something they do,” Walker said. “I think they’ve realized and tapped into something that helps them, maybe in recovery as well from pitch to pitch. … Internalizing things, keeping things in isn’t always the best thing and it’s just a way of letting it out. So I think it does free up the body for them.”

In that sense, grunting is serious in that it serves as an outlet to release pent-up energy. But it’s not lost on teammates how funny the sound can be.

“The first bullpen I ever caught against [Ray], I was just kind of laughing to myself because it’s literally every single pitch,” Giants catcher Tom Murphy said. “I think the last ball I threw back to him, I grunted back. I kind of gave him a little, ‘Hey, I got you.’’’

If Ray throws 98 pitches in a game, there’s a good chance 98 grunts will accompany. Scherzer, on the other hand, saves his vocals for bigger spots. Hill grunts to gain conviction, but he knows there’s no faking it.

There are no hard and fast rules to grunting in baseball — except for one.

During the Nationals’ 2019 championship run, Scherzer made what came to be a controversial statement: If you grunt, you have to throw 95 [mph].

“That’s my Shawn Kelley rule, actually,” Scherzer said. “[Former MLB reliever] Shawn Kelley grunted and he threw 93 and I gave him a hard time about that like, ‘That’s not cool. It’s only cool when it shows 95.’ That means you’re actually throwing hard.”

“Yeah, I’ll still stand by that,” Scherzer said.