What's fueling the rise in arm injuries across MLB? A dangerous 'cocktail' of causes

Matt Blake texted Cleveland Guardians pitcher Shane Bieber a conciliatory message over the weekend. As a member of the Cleveland player-development system in the 2010s, Blake aided Bieber’s rise from college walk-on to unanimous American League Cy Young Award winner in 2020. For a time, Bieber represented the modern model for the manufacturing of a big-league ace, a player who added strength to his frame, velocity to his fastball and spin to his offspeed pitches as he ascended the ranks.

By the time Blake sent his text, though, Bieber had become part of a growing, more troubling demographic: talented young pitchers who will spend this season as spectators. Two days after the Miami Marlins announced 20-year-old phenom Eury Pérez would undergo Tommy John surgery, the Guardians disclosed Bieber, 28, would need the same procedure. A recent examination of 25-year-old Atlanta Braves starter Spencer Strider revealed damage to his elbow’s ulnar collateral ligament, which could result in his second Tommy John surgery. In New York, where Blake is now the Yankees pitching coach, the team has lost its ace, Gerrit Cole, until June with elbow inflammation and one of its top relievers, Jonathan Loaisiga, to year-ending elbow surgery.

“As a pitching coach trying to get through nine innings worth of pitching every night over 162 games,” Blake said, “I’m pretty worried.”

Pitching has always been hazardous for its practitioners. There is reason to believe it is only getting more challenging to keep them healthy. The opening days of the 2024 season have demonstrated the inherent fragility of the position. A recent story by The Ringer cited research from former MLB trainer Stan Conte that tallied 263 UCL surgeries in 2023, a steady uptick from 111 procedures performed in 2011. Of the 166 players who began the season on the injured list, as the New York Post reported, 132 were pitchers. If these trends continue, 2024 will be another banner year for arm injuries — and cause for alarm around the game. 

The subject prompted sniping between Major League Baseball and the MLBPA on Saturday, as the two sides argued through press releases about the effect of the pitch clock, which was introduced in 2023 and shortened for 2024. MLBPA chief Tony Clark painted the league’s insistence on cutting time off the clock before the 2024 season against the wishes of players as “an unprecedented threat to our game.” MLB countered by citing unpublished analysis from Johns Hopkins University that found no link between the introduction of the clock and the surge of injuries. 

The clock, however, was just one area of concern among players, coaches and managers surveyed by The Athletic this weekend. Those conversations presented a tapestry of additional reasons for the injury problem, including the industry’s relentless push for optimization, the encouragement of players to chase maximum velocity and spin, and the usage of training methods that encourage year-round, full-throttle workouts. To some, the explanations are interwoven and intractable. Untangling the knot may require years of research and re-evaluation. 

“To protect these guys’ arms is paramount,” Dodgers manager Dave Roberts said. “And clearly we haven’t nailed it.” 

This season began with baseball’s most heralded pitchers on the shelf. Los Angeles Dodgers starter Clayton Kershaw underwent shoulder surgery last October. Texas Rangers pitcher Max Scherzer is recovering from back surgery, while his teammate Jacob deGrom is rehabbing from a second Tommy John surgery. Houston Astros ace Justin Verlander experienced shoulder soreness in spring training. All those pitchers are 35 and older, the sort of age where the body no longer cooperates with the rigors of the big-league schedule. 

For MLB, the more pressing concern is the fleet of arms breaking down soon after reaching prominence. Miami Marlins starter Sandy Alcántara, the unanimous winner of the 2022 National League Cy Young Award, underwent elbow reconstruction last season. So did Tampa Bay Rays pitcher Shane McClanahan, a little more than a year after starting the All-Star Game. Milwaukee Brewers pitcher Brandon Woodruff will miss this season because of shoulder surgery. Same story for Kansas City Royals pitcher Kyle Wright, a 21-game winner for Atlanta in 2022. 

“Our sport deserves our best pitchers to be on the mound,” Detroit Tigers manager A.J. Hinch said. “Regardless of the era you’re in, the starting pitcher matchup is the first thing you look at every day. You want the big boys out there. You want the guys that are elite, and more and more are getting hurt.”

To research the problem, MLB commissioned a study last October, which has sprawled to include conversations with 100 people around the game, including medical officials. When the study is completed, the league intends to create a task force and provide recommendations to clubs about how to keep pitchers healthy. 

The sport has grappled with the problem since its inception.  In another era, pitchers were believed to get hurt by overuse. Teams altered how they used pitchers in hopes of preserving them. Gone are the days of the exhausted starter, pushed to the brink at 125 pitches or more, trying to finish the seventh or eighth inning. The new archetype asks the pitcher not to ease into outings but explode at the outset. Go as hard as you can for as long as you can, is the new mantra. An influx of data about the shape and movement of pitches offered teams granular ways to make pitchers better. The data did not, however, offer an answer for how to keep them healthier.

“I’ve heard through my years managing that we ask less out of starting pitchers because we don’t leave them in the game long enough and they don’t throw 100 pitches as much anymore,” Hinch said. “Yet we ask them for max velo, max shape, max everything, and virtually train year-round.”

Hinch pointed to Tarik Skubal, a 27-year-old Tigers lefty who underwent Tommy John surgery in college and flexor tendon surgery in 2022. Skubal trained this past winter so that when he arrived at spring training, he touched 99 mph in his first session of live batting practice. “Go to Tarik Skubal and tell him, ‘Hey, ease it off and throw 92 mph,’ and see how that works out for you,” Hinch said. “No. Because we’re asking our athletes to compete at the highest level.”

To some retired players, the quest for elevated velocity and spin has put pitchers at risk. Dan Haren, a 13-year veteran who now works as a pitching strategist for the Arizona Diamondbacks, posted on X about his Instagram feed providing footage of “guys throwing weighted balls at max effort against a wall, with a crow hop, with his bros cheering him on.” Added Roberts, “The body is designed, in my opinion, to only take so much force and velocity before it gives way.” 

Shane Bieber hadn’t allowed a run over two outings this season when it was announced he would undergo elbow surgery. (Jason Miller / Getty Images)

Some, like Chicago Cubs manager Craig Counsell, suggested pitchers will always try to throw harder. “I don’t think the pursuit of velocity is ever going to end,” Counsell said. “Because it’s something that makes pitchers better. I don’t think we should demonize the pursuit of velocity.”

Yet the industry has championed this trend by shortening the outings of starting pitchers and encouraging them to maximize their output. Not only do pitchers throw their fastballs as hard as possible, they throw offspeed pitches with utmost force, in hopes of generating unique movement and missing bats. “The types of deliveries that create the outlier shapes are probably more stressful in some ways,” Blake said. “I think the maximization of force to create the shapes probably doesn’t help. When you’re chasing 20 inches of break or 20 inches of ride or the high velo, I think there is some level of physical cost.” 

Despite protestations from MLB officials, players will continue to complain about the clock. The innovation trimmed 24 minutes off the average game last season. The timer in 2023 granted pitchers 15 seconds to act with the bases empty and 20 with runners aboard. MLB’s 11-man competition committee voted to shave two seconds off the 20-second clock for 2024 despite objections from the players. 

Los Angeles Angels pitcher Tyler Anderson suggested pitchers might place more stress on their arm rather than their legs because of the clock. But he doubted any study could show a correlation between decreased time between pitches and increased injuries. The act of pitching was already unhealthy enough. “Rob Manfred knows it’s really hard to prove, would be my guess,” Anderson said. 

The union sees the clock as a bogeyman. The commissioner’s office sees their complaint as a straw man. For coaches like Blake, who must navigate the season as injuries continue, the clock is only part of the problem, along with the perilous chase of velocity and spin. 

“I don’t think any of them are the most responsible,” Blake said. “But the cocktail of them all is hard to get by.”

The Athletic’s Fabian Ardaya, Sam Blum, Patrick Mooney, Cody Stavenhagen contributed reporting.

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(Top photo of Strider: Justin K. Aller / Getty Images)