Why Are So Many Pitchers Getting Hurt?

The answer starts long before the majors 

Chicago baseball fans don’t need a reminder of how brutal this year has been on pitching arms. The Cubs lost top starter Cade Horton to a season-ending torn ulnar collateral ligament (UCL) after just 7⅓ innings, and reliever Porter Hodge went down with a torn UCL after first landing on the IL with a flexor strain. Shelby Miller is missing this season as he rehabs from surgery to repair a torn UCL and flexor tendon. Across town, the White Sox have watched Prelander Berroa, Ky Bush, and Jordan Leasure all miss extended time with elbow and forearm injuries.

The injury numbers across baseball are hard to ignore. The number of players requiring UCL reconstruction, commonly known as Tommy John surgery, has climbed sharply in recent years. Today, roughly one in four current MLB pitchers have had Tommy John surgery at some point in their careers.

Fans may assume it’s bad luck or that today’s pitchers are less resilient to injury than the ones who came before them. As an orthopedic surgeon who has operated on hundreds of professional and amateur pitchers, I can tell you it isn’t either of those things. It’s the predictable result of current baseball culture and its obsession with velocity.

Baseball has always rewarded a fast fastball, but in recent decades, the focus on velocity has intensified. Every mile per hour added to a pitch increases torque on the elbow, which is absorbed by the elbow muscles and a ligament the width of a shoelace. In fact, velocity is the single strongest predictor of elbow injury. My colleagues and I found fastball velocity helps predict which pitchers will need UCL reconstruction.

The trouble is that the chase for velocity now starts in adolescence, when throwing mechanics are still maturing but arm strength—accelerated by velocity-training programs, showcases, and travel-ball circuits—can outpace good form. A body that can throw hard doesn’t necessarily know how to throw hard safely.

When you pair rising velocity with volume at a young age, the risk of injury compounds. In a study of Little League pitchers, we found that exceeding recommended pitch counts in youth baseball significantly increased the likelihood that a pitcher would need Tommy John surgery years later as a professional. This means that the damage from overuse doesn’t always show up immediately.

The damage can accumulate slowly, often below the threshold of pain, until it presents as a career-interrupting injury. In a study of professional pitchers’ elbow MRIs, we found that ligament changes visible on imaging years before any symptoms appeared were significantly associated with future injured-list placement and elbow surgery.

Fatigue also plays a significant role in baseball injuries because it weakens the protection of the UCL from the flexor muscles of the elbow. In a simulated 90-pitch outing with elite 13-to-16-year-old pitchers, we tracked velocity, accuracy, and mechanics pitch by pitch. As fatigue set in, mechanics broke down. Hips fired earlier, force transfer from the lower body faltered, and pitchers began compensating with their arm instead of their whole kinetic chain. Fatigue doesn’t just slow pitchers down; it also changes how they throw, increasing the opportunity for injury.

 This pattern repeats at the professional level. In a study of complete games, we found that 74% of pitchers who threw a complete game spent time on the injured list that season, compared with just 20% of those who didn’t. High-volume pitching, whether at 14 or 24, taxes the UCL and the muscles that protect it.

Finally, these injury risks are compounded by another modern trend: year-round, single-sport specialization. More youth athletes now specialize in a single sport, often driven by competitive pressure, travel-team culture, and the appeal of early recognition.

This means many of today’s youth athletes are moving from one baseball season directly into another, with no true offseason. In fact, some are playing overlapping seasons on two teams at the same time. But evidence doesn’t show a performance payoff. Several studies of other sports found that specializing later, not earlier, was associated with elite success.

In a survey of professional baseball players, players who specialized in baseball before high school had a higher rate of serious injury during their careers than those who didn’t specialize early, and 63% of professional athletes believed specialization was not required to reach the professional level.

Pitching is not inherently unsafe, but we need to apply what the evidence tells us. As a member of MLB’s medical advisory committee, I was part of the team that developed the Pitch Smart guidelines, which give parents, coaches, and players age-specific benchmarks for pitch counts, rest days, and innings limits. They work—but only when they’re followed.

Pitch counts need to be based on age and fatigue, not just innings pitched. Young athletes need to be encouraged to pursue multiple sports rather than early specialization. Rising velocity needs to be viewed as a signal to double down on mechanics. Coaches and parents should watch for early signs of fatigue, such as a drop in velocity, a change in arm slot, or a pitcher who “looks a little different.”

Pitchers today aren’t more fragile than pitchers of the past. They’re simply being asked to throw harder, more often, and earlier in life than generations before them. And now they’re paying the price for how we’ve trained young arms. But it doesn’t need to be this way. We have the opportunity to change course and ensure our next generation of athletes enjoys the game with fewer injuries.

Anthony A. Romeo, MD, is an orthopedic surgeon with more than 30 years of experience specializing in shoulder, elbow, and sports medicine, with internationally recognized expertise in revision surgery. He is recognized internationally for surgical education and live operative demonstrations. He has authored more than 500 peer-reviewed publications and helped design widely used shoulder replacement systems and arthroscopic instruments. He is the founder of Romeo Orthopaedics in Burr Ridge, Illinois, where he helps a wide range of patients address elbow and shoulder conditions so they can get back to living their best life. Learn more at romeoorthopaedics.com.