Baseball mythology says to use the curveball sparingly — that it causes too much stress for the pitcher and can lead to injuries. But several teams and players are bucking that trend. As Sports Illustrated’s Tom Verducci noted in a recent feature, "spin is in." As fastball usage declines in the major leagues, many pitchers are relying on the curveball more and more. To learn more about the phenomenon, Michael Baumann and Ben Lindbergh brought Verducci on The Ringer MLB Show.
First off: What tipped off Verducci to the increase in curveball usage?
"It was the postseason last year, the 2016 postseason, and especially watching the Indians against Toronto — [they used a] heavy dosage of curveballs," Verducci said. "And even Cleveland against the Cubs, it seemed like the Indians were really able to tamp down that Cub lineup mostly with breaking balls. … So I got the sense that something is going on here, and that led to [me] keeping track of things in the early part of the season this year. And with Houston jumping out so quickly and the way Lance McCullers has been a sort of breakout pitcher, I thought the timing was perfect. But it went back to the postseason where I thought the curveball usage really went up."
But won’t that risk injuries? Verducci’s research indicates that it won’t.
"The one thing that really surprised me in talking to the people at [the American Sports Medicine Institute] in Birmingham — and they’ve studied this as well as anybody in terms of the body’s kinetics and the effect of velocity, and breaking balls — they have the data, and it surprised me that their data showed that throwing the curveball at an early age was not more dangerous than throwing a fastball," Verducci said. "In some cases it was less dangerous. Now I personally always have to throw in a caveat there, because if you throw any pitch too much, and you throw it with poor mechanics, those are the two biggest risk factors for injury. So a kid out there throwing a million curveballs really trying to torque his wrist and elbow [is] not advisable. But if you throw the curveball the right way, you have a good pitching coach, you don’t pitch when you’re fatigued, go ahead and keep throwing it."
For Astros pitcher Lance McCullers, the curveball is no longer a secondary pitch.
"The mind-set has changed, certainly at the big league level," Verducci said. "Lance McCullers told me that the pitch that normally, for 100 years, was thought of as a secondary pitch, as an off-speed pitch, as a complementary pitch, now he says is on the same plane in his mind as the fastball. It’s not an off-speed pitch. Well, he throws his really really hard. And it’s not a secondary pitch. He says, ‘That’s my best pitch, and I’m going to keep throwing it.’"
Now the numbers are beginning to show a steady decline for fastball usage, in part due to a heavier reliance on pitches like the curveball.
"Hitters used to see two out of every three pitches were a fastball," Verducci said. "Now it’s almost one out of every two. That’s a big change in a relatively short amount of time, and [is] kind of blowing up what conventional wisdom has always held."
Why the increase in curveballs? A big reason is technology. Umpires are better at calling strikes than ever.
"I know 15, 20 years ago, [pitchers] would walk away from their curveball because they thought they had a hard time getting it called for strikes," Verducci said. "And I think that the analytics, the data, the technology we have now has more unified the strike zone. I think the younger umpires especially are more inclined to call a big breaking curveball a strike when it does hit the zone. It’s a hard pitch to call, besides being hard to hit, but I don’t hear many pitchers saying, ‘You know what, I’m not going to throw these big breaking curveballs because it won’t be called a strike.’ I think it’s less of an issue now because of technology. The strike zone is so well-defined."
Listen to the full podcast here. This transcript has been edited and condensed.