There might not be a solution to the pitching injury problem in baseball. If you sort the research and data on the subject to answer the questions most asked about the subject, you don’t end up in a place where there’s an easy way forward.
But that exercise, of answering what we think we can answer the best way possible, seems like a worthy enterprise either way.
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What is the main source of pitcher injury?
Velocity. Throwing hard is a direct stressor on the elbow, and throwing hard has been shown to lead to injury by multiple studies over the years. One study found that fastball velocity was the most predictive factor of needing elbow surgery in pro pitchers. Every additional tick is more stress on the elbow ligament.
Are pitchers getting hurt because they are throwers, not pitchers now?
Although this has an element of shaking a fist at clouds, there’s also an element of truth in this. Glenn Fleisig, Jonathan Slowik, et al. found that the closer a pitcher pitches to their maximum velocity, the more stress they put on their elbow, and other studies have found similar answers. The bad news is that baseball, as a sport, is throwing closer to its maximum with every year. And yes, this is keeping the method of measuring that velocity constant, it has nothing to do with radar technology changes.
The hardest tracked throw remains Aroldis Chapman’s 105.7 mph in 2016, and the league’s maximum has settled in around 105 mph most seasons. But the average fastball just keeps climbing, meaning as a league, pitchers are throwing closer to their maximum. And this is true on the individual level — according to STATS Perform, the difference between the average starting pitcher’s sitting and max fastball velocity (minimum 500 thrown in a season) was down to a pitch-tracking low of 3.2 mph in 2023, and that’s more than a full tick less than where it started when pitch tracking began. Today’s baseball is a max-effort game. Unfortunately, while varying the velocity on the fastball may help a pitcher “save bullets” and reduce stress, it does not help them perform better.
Are analytics to blame?
There’s an obvious bias here between the author and the answer, but this line of questioning does not reflect well on professional pitchers’ ability to understand the risks and rewards in their own sport. In other words, yes, there have been all sorts of studies that link fastball velocity to better outcomes, starting with Atlanta Braves executive Mike Fast’s seminal piece on the subject and culminating most recently in things like Stuff+, but does a pitcher really need an analyst to tell them they need to get strikeouts, and that throwing hard will get them there? Listen to Justin Verlander on the subject. He’s smart, but he also captures the feeling of most pitchers when faced with the reality of getting outs in today’s game — especially given the rules changes that have favored offense.
Justin Verlander on the rash of pithcer injuries:
"…I think the game has changed a lot, it would be easiest to blame the pitch clock, in reality everything has a little bit of influence, the biggest thing is the style of pitching has changed so much, everyone is throwing as… pic.twitter.com/rzmvwhB27R
— Ari Alexander (@AriA1exander) April 7, 2024
Pitchers organize their talents to get outs, and pitchers know velocity is good for that. The role of the analyst, as it always has been, is to support the players in getting as many wins as possible. Don’t hate the players (or the analysts), they’re just trying to win games.
Are the injuries because of all the breaking balls?
One of the studies that looked at direct stress on the elbow for different pitch types did find that, although overall velocity was the biggest source of stress, once you adjusted for velocity, breaking balls provided more stress at any given mph. Eighty-five mph is a bit of a magic spot for breaking balls — they get better above that velocity, at least. In 2023, pitchers threw nearly 44,000 more breaking balls over 85 mph than they did when we started tracking pitches in 2008. But this is a distinction without a difference, probably: Whether it’s fastball velocity or breaking ball velocity, it’s still velocity.
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What role does the pitch clock have in injury?
Theoretically, if you ask an athlete to do the same amount of work in less time, you’re increasing their fatigue. That’s something so basic it shouldn’t require supporting research, but before Dr. Mike Sonne went to work for the Cubs, he wrote for The Athletic about how that works. And how that fatigue should lead to more injuries.
The weird thing is… it hasn’t. Yet. Not at the major-league level.
Despite an early surge in injuries in the first year of the clock, once the year finished, there was no real discernible difference in injury rates. And because March and April are the biggest months for injury list placements, it wouldn’t make much sense to report this year’s injury rates as a big predictor, not until we sum it all up in the end again. The increase in injuries on the major-league level has been a slow burn, not a big spike. The one caveat is that minor-league UCL injuries have exploded since the pitch clock was first introduced in 2018, going from 152 in 2017 to consistently over 200 in each of the past three seasons. (Then again, there were only 86 UCL injuries in the minors in 2011, so there’s more happening here.)
It’s probably most accurate to say that the clock has some role, but that role is undefined as of now, and there’s a longer trend at play, so it can’t all be the clock.
Does sticky stuff (and its ban) have any role in the injury increase?
Tyler Glasnow famously felt that banning sticky stuff led to him having to grip the ball harder, which led to his injury.
Tyler Glasnow made it very clear why pitchers were getting injured 2 years ago. It’s not the pitch clock
Nor even joking, this is all Trevor Bauer’s fault pic.twitter.com/Tr0XN8y4En
— Nate (@notNate99) April 7, 2024
Research on grip strength isn’t conclusive. Grip strength probably doesn’t lead to more spin, but could lead to better health outcomes, and doesn’t seem to stress the elbow — but these are all studies about grip strength relative to other players. There may not be a study out there that looks at what happens when a pitcher grips the ball harder than he normally does.
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But, again, there’s no real spike in injuries after enforcement. There were 243 pitcher injuries in 2021, 226 in 2022 and 233 last year. Sticky stuff enforcement happened in mid-2021.
Could year-round throwing be the problem?
“You have to build up your fitness,” said Sonne, who is a data scientist for the Cubs now. “If you’re running a marathon, you don’t not run for months so you can run on race day. The April spike in injuries happens because people STOP throwing and then try to build up.”
There might be a difference here between adult professionals and kids, though.
On pitching injuries, I'll say this: start with rigorous adherence to basic protective guidelines before tackling advanced physics/sports medicine challenges. >100 IP/yr is associated with a 350% increased risk of injury in youth arms. If you can count, you can prevent injuries.
— Eric Cressey (@EricCressey) April 8, 2024
Throwing 100 innings as your body is still developing looks like it increases injury risk. But that might also be because of the shape of those innings, the effort the young person is putting into those pitches, the amount of rest they get and how their workload was monitored. If those things are inconsistent in MLB, they’re probably near nonexistent on a concise level across youth leagues. Throwing less has been put out there as a solution … except that it doesn’t prepare them all that well for throwing more in the future. Pitchers are throwing less, everywhere, and they’re injured more.
Are there better mechanics out there that could solve the problem?
There have been findings that have come out of the emergent study of biomechanics. Certain relationships between your landing foot, your trunk rotation and your shoulder movement have been deemed better than others. Some think they’ve got the perfect mechanics that will ensure a way out of this problem. But Casey Mulholland, who runs Kinetic Pro, a private player development lab, outlined a problem with blaming it all on mechanics.
“Let’s say you’ve got a pitcher with a three-quarter arm slot — that means more stress, more valgus torque,” Mulholland said. “He comes to Tampa and I magically change his arm action to produce the same velo more over the top, and now he throws with less torque. Well, with the cleaned-up arm action, he can now throw harder. And the one thing we know that increases stress is velo, sooooo.
“Our brain passes messages to our muscles, forearm flexors in this case, via the central nervous system to contract at just the right moment to offload the stress applied to the UCL. When we become fatigued our brain doesn’t pass this message as well, the muscles don’t contract at the ‘optimal time’ or the ‘optimal amount’ and we end up not being able to offload this stress. The UCL then wears more of a direct stress. Over time, under fatigue, the load of throwing eventually overcomes the tissue tolerance and boom, UCL tear.
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“This is why workload management is the only logical answer to slow the injury rate,” thinks Mulholland. “Workload management predicts the possible time at which an athlete might experience too much load.”
What rule changes could incentivize different injury outcomes?
Some proposed rule changes are just not going to happen. Every pitch over 94 is a ball? Just can’t see it. Similarly, the idea that we will limit the number of pitchers on the roster might work to prod teams into getting more innings from each pitching slot. But the players’ union would assuredly be against any reduction in major-league jobs.
Jayson Stark’s proposed “Double Hook” — in which the pitching team loses their designated hitter once the starting pitcher leaves the game — would incentivize teams to acquire players who can go deeper into games. But there’s a little bit of a gap there that will be funky for the pitchers themselves. Until the market shows that it will value lesser quality with more quantity (it hasn’t), the pitcher’s incentives may be misaligned with those of the team as a whole. They’d rather be the guy with better stuff and cleaner numbers if they know that’s what free agency has rewarded in the past.
Limiting the number of active pitchers for a single game seems like a bland rule change that might not mean much. But, in light of Mulholland’s and Sonne’s feelings about the importance of workload monitoring, maybe asking teams to fully rule out some number of pitchers every game could nudge teams into the era of more precise workload management.
In the end, there’s no telling pitchers to throw softer if it isn’t going to help their bottom line — and that’s sort of the simplest way to state the problem. The best we can do as a sport is to provide players with the best possible mechanics that analysis can provide, and be as precise as possible with monitoring their fatigue. At the very top of any game, injuries will happen.
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(Photo of Justin Verlander: Carmen Mandato / Getty Images)
