The Velocity Trap

The ulnar collateral ligament, or UCL, is a triangular set of bundles in the human elbow that looks like three crisscrossing strips of bacon—a marvel of physiology that functions as the crucial hinge between the humerus, in the upper arm, and the ulna, in the forearm. But as Jeff Passan memorably describes it in his 2016 book, The Arm: Inside the Billion-Dollar Mystery of the Most Valuable Commodity in Sports, the UCL is also “a finicky little bastard, ill-equipped to stand up long-term to the single fastest movement the body can generate: the throwing motion.” A pitcher’s arm whips through the air “30 times faster than an eyeblink,” he writes, and all of that power and torque gathers in the elbow, leaving the UCL “screaming for mercy.”

Somewhere along the evolutionary path from chimpanzee to human, we went from having arms that weren’t even equipped to throw overhand to being able to wing a baseball in excess of 100 miles per hour—and do it with such precision that batters can stand inches from its path without getting drilled in the head. The data get fuzzier the further back you go, but according to the stat-tracking website FanGraphs, the average fastball in Major League Baseball was about 89 mph in 2002. A decade later, it had jumped to 91.6 mph. In 2022, it was 93.6 mph. Last year, the Minnesota Twins reliever Jhoan Duran led the MLB with an average fastball velocity of 101.8 mph. The record belongs to Aroldis Chapman, then with the Cincinnati Reds, who threw a baseball 105.8 mph in a September 2010 game against the San Diego Padres. The fact that his record has stood for 14 years while everyone around him has been throwing harder and harder makes him the Bob Beamon of Major League Baseball. But that record’s days are almost certainly numbered.

In tandem with fastball velocity has risen another closely watched statistic: catastrophic arm injuries, with UCL tears being by far the most frequent. “The graphs essentially overlap each other,” Glenn Fleisig, the director of biomechanics at the American Sports Medicine Institute (ASMI), told me. Back in 2010, MLB pitchers made 241 trips onto the injured list. Last season, that number was 497. Arms are flying off their hinges all over the place, to the degree that it’s become a routine part of the game. Back in 2012, Scott Boras, baseball’s most powerful agent, told Passan that Tommy John surgery—baseball vernacular for a UCL-repair procedure, named for the Los Angeles Dodgers pitcher who was its first successful recipient in 1974—“may be a rite of passage, for all we know.” Now we know: It is. And that’s starting to feel a little barbaric.

Fewer than 10 games into this season, over only a 24-hour period last week, two of the league’s elite starters went down with elbow injuries: the Cleveland Guardians’ Shane Bieber and the Atlanta Braves’ Spencer Strider. Bieber, the American League’s Cy Young Award winner in 2020, will need Tommy John surgery and is out for the year. Strider, MLB’s strikeout leader last year, thanks in large part to an average fastball of 97.2 mph, seems bound for the same fate. A few days earlier, the Miami Marlins had announced that 20-year-old Eury Pérez, their top pitching prospect, will undergo Tommy John surgery and would miss the season, joining the team’s ace, the 2022 National League Cy Young award winner Sandy Alcántara, who got Tommy John surgery last October.

Most pitchers do go on to play at the same level after Tommy John surgery. The procedure even comes with a kind of morbid warranty: A freshly repaired UCL is thought to be rock-solid for about eight years before it starts to deteriorate again. Even the athletes seem at peace with it. If a professional pitcher manages to have a career that lasts eight or nine years, we should “expect him to miss at least one of those years,” Tyler Zombro, a minor-league reliever who coaches MLB prospects at the pitching academy Tread Athletics, told me. “People have just begun to embrace that, for both better and worse.” After the Marlins announced that Pérez would need surgery, the team’s president of baseball operations told reporters that Pérez was “frustrated … but he also understands that this is a minor setback in what’s going to be a really long career.”

A pitcher’s arm can fail for any number of reasons—overuse, bad mechanics, poor conditioning. For the past decade, overuse was considered the prime culprit, which is why starting pitchers now routinely get pulled after 100 pitches—a far cry from the night in 1974 when Nolan Ryan threw 235 pitches over 13 innings—and why relievers seem to enter and exit the game through a revolving door on the mound. And yet, injuries keep piling up.

“If we had this conversation a dozen years ago,” Fleisig told me, “I would say strongly that the amount of pitching is the biggest factor for why we’re seeing so many pitching injuries. Now I’d say that’s moved into the back seat, and the No. 1 factor is throwing as hard as you can.”

The correlation between velocity and arm injuries has become strong enough that maybe it’s time to ask a basic question about the game: Are pitchers today throwing too hard for their own good? The simple answer is yes—certainly in medical terms, at least. But good luck getting anyone in the sport to slow them down, for one simple reason: Throwing hard works.

Baseball is caught in a velocity trap. If you examine the relationship between pitch speed and swinging strikes, “it’s almost linear,” says Rob Friedman, a.k.a. the Pitching Ninja, whose Instagram account dissecting the game’s filthiest pitches has become a destination for many fans multiple times a day. Last fall, Friedman posted a compilation of every pitch in 2023 thrown over the middle of the plate that clocked 102 mph or above—27 in total. Only two resulted in hits. “It’s very hard to hit a very hard fastball, even if it’s right down the middle,” he told me. “That’s why pitchers do it, and I don’t think it’s going to change.”

“What we have to do as an industry is figure out how to reconcile two things,” Eric Cressey, a co-founder of Cressey Sports Performance and the Yankees’ director of player health and performance, told me, “which is that high performers do tend to throw harder, but hard throwers do tend to get hurt.”

Teams, front offices, coaches, players, fans—we’re all addicted to the velo. (That’s pronounced vee-lo, by the way, not veh-lo.) Part of the reason we love sports is the goosefleshy thrill of watching someone do things we never could, and maybe something no one’s ever done before, like throw a 106-mph fastball. Pitches thrown that hard even sound different when they hit the catcher’s mitt—more of a snap than a pop. That’s one reason fans have become so cavalier about major arm injuries. We do the math—12 to 14 months is the standard recovery time for a Tommy John—and then we put the player out of our heads until he’s back. MLB front offices have come to look at pitchers as data on a spreadsheet. One arm breaks, and you replace it with another; Zombro called it “the churn.” The long-term risk to a player’s health isn’t the primary concern of a general manager who’ll get fired if he doesn’t win now.

What we’re glossing over is the hellish months of rehab, the mental anguish of fearing that your career could be over, the loneliness of being out of the game. “We’ve become numb to it,” Alan Jaeger, a strength and conditioning coach who has consulted for various MLB teams, told me. His chief claim to fame is inventing the long toss, a now-routine arm-strengthening technique. “The front offices are numb to it. And then the players then feel numb to it, because they feel like they’re just a number.”

One reason we’ve all gotten so numb is the perception that a full recovery is virtually inevitable. But not all pitchers regain their previous form—Fleisig puts the number at about 80 percent. That's a high rate, but imagine how you’d feel if it was your career in the hands of a surgeon.

The velocity trap hasn’t just ensnared the major leaguers, who are paid—many of them quite well—to take such risks. It’s affecting Little Leaguers, who are mimicking the pros on TV, firing the ball as hard as they can, with arms that are far from ready for such violent exertion. High-school prospects know that the only way to get the attention of a college recruiter or a pro scout is to light up the radar gun. Minor leaguers who throw 100 mph but can’t keep it over the plate are far more prized than prospects with elite control who top out at 93 mph. If playing in the big leagues requires pushing your elbow beyond its breaking point, plenty of people will make that deal. “I mean, would you take $20 million to tear your UCL?” Friedman asked. (For what it’s worth, you can have both of mine.)

From 2011 to 2013, six pitchers selected in the first 10 rounds of the MLB draft had a prior history of UCL-reconstruction surgery—they’d blown out their elbow, in other words, before they’d thrown a single professional pitch. From 2021 to 2023, that number went up to 24. So are more teenagers getting elbow surgery, or are teams getting less spooked by it? Yes and yes. “There isn’t a normal elbow coming out of amateur baseball now,” Cressey told me. “The injuries are happening so much younger.”

In 2014, MLB partnered with USA Baseball to create Pitch Smart, a series of guidelines on pitch counts and rest periods intended to keep young pitchers from developing bad habits. Anyone who’s coached a Little League team knows that they are strictly enforced. Fleisig believes the Pitch Smart program has been a success: Arm injuries at the pro level have declined ever so slightly since 2021. But with around 500 trips to the injured list for each of the past two years, this is hardly a victory.

The solution remains elusive. Randy Sullivan, a performance specialist and the founder of the Florida Baseball ARMory, points out that if overuse were the primary cause of arm injuries, we’d see more late in the season, when arms are getting tired, and fewer at the start—but it turns out the reverse is true. Jaeger, in fact, has a borderline-heretical view on the question of overuse: He thinks young pitchers aren’t throwing enough. Just because a teenager can hit 95 on the radar gun doesn’t mean he’s ready to throw 95. Muscle networks across the body—quads, glutes, obliques, and the all-important shoulders, biceps, and forearms—need proper conditioning, and right now, Jaeger told me, “we’re shocking these arms.” He likens it to training for a marathon by sprinting a mile every day.

At this point, no one seriously doubts the link between velocity and arm injuries. But among experts, your particular favored solution tends to depend on your line of work. Jaeger, a strength and conditioning specialist, believes the antidote is better strength and conditioning. Jim Curnal, a Connecticut-based pitching coach who runs a clinic for high schoolers that focuses on the mechanics of throwing form and motion, believes that all these arms are blowing out because of poor mechanics. Legendary workhorses such as Steve Carlton and Nolan Ryan pumped fastballs just as hard, he told me, and far more of them too, and they never broke down. He emailed me photo after photo of pitchers with repaired elbows whose throwing motions, he claims, should’ve been a warning sign—a forearm too parallel to the ground as the shoulders begin to tilt, when it should be perpendicular, or a back foot floating off the ground as the ball is released, when it should be planted.

To one degree or another, everyone is right: A janky delivery can wreck an arm. But the notion of predicting injuries from photos, Friedman said, is “hocus-pocus voodoo science.” Every pitcher’s physique is different, he observed; “I don’t buy just visually looking at it and saying, ‘Oh, that guy’s going to get injured.’” Some guys are lucky to be born with a naturally thick UCL, he said. Some guys have thin ones.

Maybe it’s not just the speed of the pitches but also the shape of them. Today’s athletes are throwing pitches commonly referred to as “off-speed”—sliders, sinkers, sweepers, which break sideways like a broom—as hard as they can. “Guys are trying to sweep the ball, carry the ball, sink the ball, throw depthy curve balls, pronate changeups,” Zombro told me. “Would I say, ‘Are guys throwing too hard?’ No. Guys throwing hard and trying to manipulate the ball in a ton of different ways? That certainly could be a risk factor.”

Injury prevention is a game of whack-a-mole, and the moles are undefeated. If anyone is going to come up with a solution, it won’t be the franchises, and it certainly won’t be the pitchers, whose careers depend on getting outs. It’ll have to be Major League Baseball itself.

And so far, according to Kyle Boddy, the founder of Driveline Baseball and a special adviser to the Boston Red Sox, the league hasn’t done nearly enough. Like many people in the sport, Boddy has reflected on the cognitive dissonance his job requires—the imperative to maximize a pitcher’s “stuff” and the reality of what it’s doing to his arm. “It’s very frustrating, and I do think a lot about how Driveline impacted that and how we could do a better job,” he told me. There’s only so much, though, that one clinic can do on its own. He likened the issue to “banning smoking in restaurants. If any one restaurant does it, they lose business. When you have this obvious failure that no single actor can solve, then it’s time for the state or the federal government to step in.”

One strategy he volunteers: shrink the number of pitchers that MLB teams can carry on their roster, curb the shuttle bus between the minors and majors that teams use to bring in reinforcements, and force them to invest more resources into preserving the arms they have.

The damage to pitchers’ arms is starting to damage the game itself. Jacob deGrom, Gerrit Cole, and Justin Verlander—three of the most recognizable names of the past decade—are all recovering from arm injuries and haven’t pitched yet this season. That’s a massive amount of star power missing from the game, and it’s being replaced by league-average starters whom no one’s paying to see. The back-to-back injuries to Bieber and Strider last week seemed to snap baseball’s leadership to attention. But instead of addressing the root issues, the executive director of the MLB players’ union, Tony Clark, used the occasion to take a shot at management, blaming the injuries on its decision to shorten the allowable time between pitches to speed up the game—even though there’s little evidence of a correlation between arm injuries and the pitch clock.

Considering all the variables that contribute to the velocity trap, perhaps it’s worth examining the assumption at its core: Does velocity, in fact, always work as well as advertised? There’s a big difference between throwing and pitching, Boddy pointed out, and three-digit velocity isn’t much use if you can’t control it. “All these people are throwing 100 in the big leagues,” he said, “and they’re not even good.”

During spring training in March, Friedman posted a clip on Pitching Ninja of a 6-foot-6 then-19-year-old in the Washington Nationals system named Jarlin Susana throwing a 103-mph fastball. Susana had pitched professionally for only two seasons, and the second season had not gone well. He’d gotten rocked, walking 40 hitters in 63 innings and posting an unsightly 5.14 earned-run average. He’d been so generally ineffective that the Nats had demoted him—from their lowest level—and sent him to work off the field with team instructors.

Now here he was, five months later, at a showcase game for promising minor leaguers. Only two explanations seem possible: The Nats are still believers because, wow, a 19-year-old who throws 103 mph! Or the Nats are dangling him in front of the league, hoping some other team will be so tantalized by his pure, uncut velo that they’ll trade someone of real value for him. Either way, the odds are against Susana. His lack of command will likely derail him—or his elbow will.

Aroldis Chapman, baseball’s reigning velocity king, is a very different player. A seven-time All-Star closer, he’s still pitching at 36 years old and, it bears mentioning, has never needed surgery on his arm. After he uncorked that record-setting 105.8 mph pitch against the Padres and the speed flashed on the scoreboard, the fans at Petco Park let out a collective “whoa,” loud enough to be audible on the replay. But the pitch was way inside. It was the hardest pitch ever thrown. It was also a ball.