PITTSBURGH — Spin rate is the measure of how often a baseball rotates around its axis after a pitcher lets the ball go toward home plate.

It’s something that’s always existed in baseball, and spinning the ball is how breaking pitches were invented. A curveball will have a very high spin rate, with pitches with less break having progressively less and less spin. A well-executed knuckleball should have nearly none.

The more RPMs a pitcher can put on a pitch, the more it’s going to be able to break, and so spin rate is particularly important for learning how to execute breaking pitches. In order for a pitcher to consistently located a pitch that might have two or even three feet of break, they have to also be consistently spinning the ball at the same RPMs so that it breaks the same amount.

All of that has been done for years by touch and feel and practice, but thanks to the data from Statcast, it can now also be quantified.

Spin rate can also be important for fastballs, too. A hard, flat fastball is going to get hit more than a slower fastball with more movement. That’s why Trevor Williams’ outcomes have gotten increasingly better as he’s pulled back on his fastball velocity over the last season.

Most in baseball believe that the spin rate on a pitcher’s fastball is at least someone innate. Some pitchers can throw the ball harder while still spinning it, while others cannot.

“Everybody is different,” Pirates catcher Francisco Cervelli explained. “It’s like [Trevor Williams]. Willy throws 90 miles per hour. His fastball is invisible sometimes. He’s got something special.”

But there are also ways that a pitcher can enhance the natural movement of a fastball. One, like Williams has been experimenting with, is to throw it easier. There are others, as well, and there’s a big enough advantage to having a fastball with a better spin rate that most are willing to try some things to figure out how to get one.

“I think it’s something guys have, but as they grow and mature physically and also mentally, they can add into it, because they have more of an awareness of their release point and how they want to throw the baseball,” Pirates pitching coach Ray Searage said. “It gives it more life at the end of the pitch, the ability to have a little bit of jump to it, a little bit of run to it, or the ability to have a little extra on the cut if it goes that way.”

Former Pirates starter Gerrit Cole has seen his spin rate increase a good bit since he’s been with the Houston Astros, rising from an average of 2,163 RPM with the Pirates last year to 2,339 in Houston — about an eight percent increase.

The big bump in spin rate drew some attention as people attempted to rationalize the big improvement in Cole’s results. Travis Sawchick of Fangraphs first publicized the changes in Cole’s four-seam fastball, and after his article was released, many on Twitter had an opinion about the change.

Kyle Boddy, a pitching coach with Driveline Baseball in Seattle, accused Cole of using pine tar or Firm Grip, both banned substances for pitchers that allow them to hold onto the ball longer while throwing hard, increasing their ability to spin the ball.

Cleveland Indians pitcher Trevor Bauer, who went to college with Cole, said he knows that he could add 400 RPM to his fastball with pine tar. Cole didn’t see that kind of drastic change.

But there are other ways. The best one, in fact, comes from making an adjustment to the pitcher’s release point, according to Searage.

“Most definitely,” he said. “It’s gotta be out in front. If it’s on the side of the head, you’re underneath and behind the ball. You want to stay on top and behind the ball.”

That’s interesting, because a Searage disciple that’s made an adjustment to his release point has also seen a huge change in spin rate. Pirates reliever Tyler Glasnow’s four-seam fastball has been spinning at 2,462 RPM this year, according to Baseball Savant. In 2017, it was 2,220 — an increase of about 10 percent, bigger than Cole’s, and in fact, the biggest in all of the majors.

Glasnow isn’t using pine tar. But an increase in spin rate is what he was getting at when he made changes over the offseason to throw the ball more over the top and let the natural cut to his fastball play.

“It’s just putting your body in a position to put more force on it,” Glasnow said. “It’s not really that I’m trying to throw for a higher spin rate, it’s that I’m trying to get more behind the ball.”

Glasnow thinks that with him, in particular, the spin of his fastball was something that was missing. He has one of the closest-to-the-plate release points in baseball, meaning that his effective velocity has always been much higher than the radar gun reading, but his fastball was still very hittable in the past. What he needed was movement.

“(Movement), mixed in with (extension), means the ball gets on you a little quicker,” he said. “It’s just a little deception.”

Of course, Glasnow has always had the ability to let his fastball cut with its natural spin, but he hasn’t always been able to control that.

“He always had the spin rate, but the consistency of it didn’t really materialize,” Searage said.

The disadvantage of making a structural change to his throwing motion for the sake of the spin rate on his fastball is that he has to use that throwing motion for all his pitches. Suddenly, his curveball has a lot more break, too. That’s one reason he’s spiked a few into the dirt this season. He’s still getting used to the feel for the way his breaking ball comes out of the hand from his new delivery.

His changeup has been the biggest hurdle there, and that’s why he’s focused mostly on his four-seam fastball and curveball so far.

“We haven’t taken away the changeup, it’s just that the opportunities haven’t arisen in order for him to throw them in the game,” Searage said. “The curveball has been the pitch that works really good. The changeup has been a little erratic, but we haven’t gotten rid of that pitch. It’s still in the repertoire.”

On the whole, it’s a drastic adjustment to be making in the majors, especially for a pitcher without much Major League experience, but the Pirates seems to have carved out a low-leverage role in the bullpen for Glasnow to get his feet wet with this new approach and see how it plays against big-league hitters.

Glasnow has always had the size and the arm strength to throw the ball hard. If he can master these changes to make it hard, with movement, it could be a game-changer.

IMPORTANT: You will need to update your password after the switch to the new server in order to log in and comment. Go to the Password Reset Page to change your password.