MLB releases report on injuries to pitchers

Over the last year, in an effort to better understand the rise of pitcher injuries, Major League Baseball interviewed over 200 experts from all areas and levels of baseball.

The goal was to begin the process of identifying the root causes of pitcher injuries, which have increased over the last several decades, and to generate ideas that might ultimately lead to solutions that prevent those injuries in the future.

Former Major League pitchers, orthopedic surgeons and sports medicine physicians, biomechanists, current MLB pitching coaches, athletic trainers, club officials and front office executives, player agents, independent pitcher development coaches and amateur baseball stakeholders were all surveyed for their insight.

The results of the study were published on Tuesday in MLB's Report on Pitcher Injuries.

It's intended to be the foundation of the long-term journey toward keeping pitchers healthy -- to provide a 360-degree view on pitcher injuries from people across amateur, college, Minor League and Major League Baseball, so that the next phase of research can be undertaken, with a better understanding of what areas should be investigated.

"This is a first step, and an encouraging step," said Dr. Glenn Fleisig, the director of biomechanics research at the American Sports Medicine Institute and injury research adviser to MLB. "When you're trying to develop players safely, the important thing is to be working on the right things, and not going in the wrong direction. I think this is an important first step in giving us the right direction to go."

Here are some of the key takeaways from the MLB Report on Pitcher Injuries:

1) There was a broad consensus that pitchers chasing max-effort velocity and "stuff" is driving the increase in injuries.

The majority of pitchers, coaches and medical professionals interviewed in the study agreed on three main factors contributing to the rise of pitcher injuries in professional baseball today:

• Pitchers trying to throw with more velocity
• Pitchers pursuing nastier "stuff" through pitch design
• The emphasis on "max-effort" training and max-effort pitching in games

Since the introduction of pitch tracking in 2008, Major League fastball velocities -- and the velocities of other pitch types -- have climbed higher and higher. That increase in velocity has correlated with the increase in pitcher injuries over the same time period.

"I think there are a lot of factors. There’s no question that if we take the simplest thing, which is fastball velocity, you can see how the average increase in fastball velocity has completely paralleled the increased incidence of injury. If you could take one factor, it’s that," said one orthopedic surgeon quoted in the report.

When an individual pitcher throws harder, it increases the torque and stress on his elbow. The number of Tommy John surgeries -- reconstructions of the ulnar collateral ligament in the pitching elbow -- has risen in professional baseball alongside fastball velocity.

But it's not just fastballs. Pitchers are now chasing "stuff" -- velocity, spin and movement -- on all their pitches, especially with all the tracking technology now available to them. Teams value pitches with higher stuff grades, so pitchers work to attain certain measurables, both during the year with their MLB team and often in the offseason with independent pitch development labs. That also might be increasing stress on pitchers' arms.

"With all the modeling of pitches that goes on now, it’s very binary that higher velo with a better shape is going to yield more positive outcomes. It’s hard for guys to step off the gas because it’s me versus you, and if I’m going to give less than my best effort, and if you hit it over the fence, I’ll be kicking myself because I know I could’ve done more," said a pitching development executive from one MLB team.

Pitchers throwing as hard as they can, or their nastiest breaking ball, with maximum effort every pitch is the combination that the experts surveyed agreed was the likeliest cause of arm injuries. That consensus will help MLB focus its research going forward.

"If we interviewed 200 people, I was concerned that we'd get 200 different answers," Fleisig said. "The fact that there was agreement in this report -- that most people think the No. 1 issue is velocity -- is great. The survey does not prove what the issues are, but it shows us what people [in baseball] think the issues are. So it gives us a gameplan or roadmap for what we should try to solve."

2) Recent injuries to star pitchers have brought increased attention to pitcher health, but pitcher injuries have risen steadily for the last two decades.

MLB commissioned this study in the fall of 2023. Between then and now, the list of star pitchers who've missed time on the mound due to significant arm injuries includes aces like Jacob deGrom, Spencer Strider, Shane McClanahan, Shane Bieber and Shohei Ohtani.

Those big names bring extra awareness to pitcher arm injuries -- but it's really part of a longer trend of rising pitcher injuries, not just a new spike over the last few years.

The MLB study sought to gather a wide range of opinions on the causes of that trend, all in one place. But Fleisig has been working with MLB's research committees to analyze pitcher arm injuries for years.

When he started studying the issue over a decade ago, the primary cause the research identified for the rise of Tommy John surgeries and other pitcher injuries was overuse -- it was the first generation of pitchers coming into the Major Leagues who'd grown up playing baseball year-round, and they were entering professional baseball with damage already in their arms.

Based on that research, MLB worked with USA Baseball to introduce "Pitch Smart" guidelines for young players. But then a new issue arose, the one the study identifies now: the chase for velocity and stuff.

"We've known [about the pitcher injury trend] for a while, and we've been studying it," Fleisig said. "And just when we were getting a grip on the primary problem of overuse, velocity -- chasing velocity -- has emerged as the new problem, and now we have to get a grip on that."

3) But in recent seasons, the injury spike is happening in Spring Training. Pitcher injuries have held steady or declined in-season.

It's not so simple as "MLB pitcher injuries are going up every year," though.

The peak time for the occurrence of pitcher injuries has shifted over the last few years -- the most injuries are now happening before the start (or at the very start) of the MLB regular season, from Spring Training through Opening Day.

Looking at pitcher injuries year over year, the number of pitchers going on the injured list in-season has started to trend downward over the last four seasons, going back to 2021. And on the whole in recent seasons, pitcher injuries have dipped after Opening Day, then remained steady or declined over the rest of the season.

That is a phenomenon that MLB's Report on Pitcher Injuries sought to gather expert opinions on in particular. The MLB Research Committee even discussed it at the Winter Meetings.

"This is something we've been talking about for a few years within the medical community of baseball," Fleisig said. "For the last few years, we've noticed that the highest time for injuries is March and April in professional baseball, when Spring Training and the season is starting. So this is part of what we have to solve as well."

One proposal suggested by those interviewed for the Report on Pitcher Injuries was that changes in pitchers' offseason training -- namely the increased focus on improving their arsenals through velocity gains, pitch design and mechanics changes, especially at private facilities with limited time windows to realize improvements -- have led to higher injury risk as they ramp up for the season.

"We go from [the] season ending to offseason programs because we want to add velocity or a breaking ball. They don’t get any time off. They want to start spinning the ball and they’re never giving the arm a break," one former Major League pitcher said in the study.

"When is the time for pitch design and time to tinker? The offseason," said another former pitcher. "They say in golf that you practice on the range and you play on the course. You can’t try new swings on the course. In the season, your slider is your slider unless the anatomy of that pitch really takes a dive. But during the offseason, if you’re not designing and refining, then guys are passing you by."

4) Major League Baseball and amateur baseball are interconnected.

The experts interviewed in MLB's Report on Pitcher Injuries pointed to a "trickle-down" effect from the Major Leagues to amateur baseball.

In other words, the same factors that they identified as potential injury risk factors for big leaguers -- chasing velocity gains and stuff improvements, and max-effort pitching -- could also be affecting youth, high school and college pitchers.

Because Major League teams value stuff and velocity, and Major Leaguers today are encouraged to pitch all-out for shorter stints, amateur pitchers now train to achieve those same qualities at younger ages.

"Guys are seeing big leaguers throwing hard in short bursts. The radar gun is in their face more than it ever has been," one college coach said. "Kids today know the [velocity] and metrics of every pitch. The last thing that goes on someone’s recruitment profile is ERA. It’s all velocity, spin rate, vertical break."

Pro and college teams recruiting players at showcases also encourages amateur players to max out their velocity.

The number of pitchers throwing 95 mph or harder at the Perfect Game National Showcase, for example, has increased dramatically over the last decade.

"I just think for the system kids are in -- chasing rankings and scholarships, possibly being the highest [Draft] pick -- velocity is king," said another college coach.

Though the data for amateur baseball isn't as comprehensive as it is at the MLB level, the data reported by organizations like the American Sports Medicine Institute suggests that pitching injuries are growing more frequent and severe at the youth and high school level.

And more pitchers are being drafted by MLB teams today with a pre-existing history of UCL surgery.

The consensus among the baseball industry experts interviewed by MLB is that a player's injury history as an amateur is a significant contributing factor to their injury risk as a pro -- there's a common saying in baseball that "the best predictor of future injury is past injury."

In that case, changes in baseball aimed at reducing pitcher injuries could have to be twofold: at the professional and amateur levels.

"We are planning to figure out what we think is right, and then work with the amateur organizations to inform them and persuade them and collaborate with them to try to make some changes at the amateur level as well," Fleisig said.

5) There's a lot more work to come.

The MLB Report on Pitcher Injuries is not a "mission accomplished" statement. It's just the beginning.

With the baseball community's opinions laid out in one place, it sets the stage for future dialogue, and action to stop pitcher injuries.

And the report does recommend some general solutions and further areas to research.

First, it suggests that professional baseball consider rule changes that would "increase the value of pitcher health and durability, and decrease the value of short-duration, max-effort pitching" -- for example, rules encouraging starting pitchers to pitch deeper into games.

Next, it recommends changes at the amateur level, including updating the Pitch Smart guidelines and giving young pitchers more rest and recovery time, particularly during the showcase calendar.

And lastly, the report recommends additional research in areas such as:

• Offseason pitcher training and pitcher early-season workloads
• Pitchers' non-game training activities
• Biomechanics and pitching styles
• Measuring pitcher fatigue
• Pitcher injury trends and injury management in foreign leagues like Japan's NPB and Korea's KBO
• Amateur baseball's injury risk factors
• The injury rate of amateur players in the U.S. vs. amateur players from other countries

Research in all those areas, the report concludes, would help continue efforts to identify the causes of pitcher injuries and work toward reducing them.

"Major League Baseball is investing the time and personpower to do this," Fleisig said. "MLB is trying to understand and prevent the injury epidemic. I think this helps to point out that we are serious about this."