Like everyone else in and around baseball, I’ve been following the conversations about the persistent prevalence of pitcher injuries, specifically the straining and tearing of the ulnar collateral ligament (UCL) that leads to Tommy John surgery. Eury Pérez, Shane Bieber, Spencer Strider, Nick Pivetta, Jonathan Loáisiga, Trevor Gott, and Josiah Gray all landed on the IL within the first couple of weeks of the 2024 season with some manner of elbow injury, renewing concerns for pitchers’ health that have become an annual April tradition over the last decade or so.

There’s no consensus as to the cause of all these elbow injuries, and there’s even less agreement on how to prevent them, but most agree a solution is needed. As I listened to prominent figures in baseball weigh in on the issue, an idea for a new rule began to formulate in my mind, something akin to a high velocity usage tax. I threw some publicly available injury and usage data at it, and it held up well enough for me to feel comfortable unleashing it from the confines of my skull to run free in the world. Essentially, my proposal would cap the number of innings that harder-throwing hurlers can pitch in a season, while also limiting the pitchers on a roster and curbing roster management protocols to avoid churning through max-velo pitchers as they reach the innings threshold. I’ll go into greater detail of my proposal a little later, but first, let’s run through some of the possible causes of the elbow-injury problem, as well as some of the suggested solutions to it.

The most recent round of discourse kicked off with the MLBPA taking aim at the pitch clock for cutting into pitchers’ recovery time between pitches, which was promptly undercut by comments from some of the PA’s own members. Many also noted that research done by Johns Hopkins when the pitch clock was implemented in the minors showed no increased injury risk, and that the upward trend in elbow injuries predates the pitch clock by several years.

The most recent round of discourse kicked off with the MLBPA taking aim at the pitch clock for cutting into pitchers’ recovery time between pitches, which was promptly undercut by comments from the PA’s own members. People also pointed out that research done by Johns Hopkins when the pitch clock was implemented in the minors showed no increased injury risk, and that the upward trend in elbow injuries predates the pitch clock by several years.

Alternatives to the pitch clock theory include increases to pitchers’ velocity, workloads that incentivize max effort, flawed mechanics, year-round training, under-studied training methods, and pitch design altering grips and deliveries in a way that adds stress to the elbow. Realistically, there probably isn’t a singular cause. Rather the confluence of everything pitchers need to do to compete at an elite level creates a hazardous work environment for elbow ligaments. And thanks to the increased availability of technology and data, the arms race to gain a competitive edge now runs at warp speed.

Speaking about the circumstances pitchers face during a Sunday Night Baseball broadcast last month, former Cy Young winner, David Cone, summarized how pitchers conduct their bullpen sessions by looking over data that track their spin rates, movement, velocity, and approach angles between every pitch. Cone highlighted the crux of the issue: “[Pitchers are] chasing a metric. They’re chasing a mathematical equation that has data behind it that shows that this is more successful. And they’re right. It doesn’t take a genius to say, if you throw harder, at a higher velocity, with more effective movement or tighter spin, it’s going to be harder to hit.”

Pitchers are incentivized to prevent runs at all costs and teams feel more comfortable if they can do it in a measurable and projectable way. As part of an in-game interview during that same broadcast, Tyler Glasnow offered his thoughts on the spate of UCL injuries. “Everyone throws a billion,” said Glasnow, who had internal brace surgery after tearing his UCL in June 2021 and didn’t return until late September 2022. “I think even from when I was in high school the mentality around that, from like 2011 and onward, was very much like just throw really hard. You’ll get more scouts.” Even if pitchers had concerns about the health of their arm, those thoughts were swept to the side because, as Glasnow recalled, “The goal of all this is to get to the big leagues and you can figure out all the other stuff later.”

An anonymous pitcher who has undergone Tommy John surgery expressed similar sentiments in an article for Baseball Prospectus, “I think I speak for the dominant portion of pitchers when I say that most of us will take the higher injury risk associated with throwing harder in exchange for a better chance of getting hitters out.” The pitcher also noted that high velocity is perhaps the most proven commodity for getting outs and that adding a couple ticks of velo is a more straightforward task for many pitchers than improving other pitching characteristics, like command.

The current incentives clearly prioritize improving measurables over preventing injuries. As the anonymous pitcher puts it, “Nobody who has entered the professional ranks as a pitcher did so because they wanted to make sure they never hurt their arm.” The pitchers who make it to the major league level want to stay there and they want to win; the rewards of that are worth the injury risks, full stop.

Major league pitchers are unlikely to stop chasing metrics on their own, so the league needs to be the one to shift the incentives for pitchers. But given all the theories floating around, with varying levels of evidence to back them up, where does MLB even start? Recently, The Athletic proposed four rule changes to reduce pitcher injury rates and ran them by MLB executives. Each proposal had its merits, but none received rave reviews from front offices. Former Phillies R&D staffer Lewie Pollis, pitched an increased penalty for hit-by-pitches, primarily in the name of reducing strikeouts, but pitchers swapping velocity for command to avoid a costly HBP would likely bring the added benefit of cutting down on UCL injuries — not to mention fewer injuries on HBPs. The main downside to this approach is the in-game penalty would impose a more dramatic disturbance to the rhythm of the game.

Any new rule proposal should rely on the existing research surrounding UCL injuries. The most researched variables are velocity and workload, followed by some studies measuring the elbow stress associated with different types of breaking balls. Dr. Glenn Fleisig’s name appears on almost all of the major studies, and last month, he told Ben Lindbergh of The Ringer that there are “three main injury risk factors for pitchers: effort (which manifests as velocity), volume of pitching, and mechanics,” with velocity clocking in at number one. Lindbergh somewhat dismisses pitching volume as a factor for professionals, citing the sharp decrease in both pitch counts and innings totals in recent years. Even so, he notes that although pitchers aren’t on the mound as often as they once were, they are throwing closer to max effort a greater proportion of the time they do spend on the mound, which suggests that some workloads put higher stress on the elbow than others.

Since the current research points to velocity and workload as it pertains to the usage of max effort or high velocity pitches as the likely highest contributors to UCL injuries, my proposed rule focuses on workload as a function of velocity, though its framework could be adapted or expanded to focus on other metrics as well.

To be clear: We can’t put a blanket ban on pitches topping a certain velocity without dramatically altering the flow of the game. Lindbergh suggests limiting the number of pitchers permitted on a roster as a means of incentivizing starters to pitch deeper into games, which in turn, would likely require throwing max effort less often. My proposal also incorporates a roster limit on pitchers, but extends the theory behind it in a more targeted manner to protect pitchers with the previously alluded to use tax.

Say every pitcher, regardless of role, starts the season with an allotment of 180 innings (roughly the median IP for qualified starters over the last three seasons), but the 180-inning cap only kicks in if a pitcher throws more than 15 pitches over 95 mph. Meaning pitchers who pride themselves on eating innings can still aim for 200, if they are willing to keep their velo in the mid to lower 90s. Once a pitcher logs 15 pitches harder than 95 mph, the 180-inning cap goes into effect (including innings already thrown on the season). The first 15 pitches act as a buffer, a few freebies doled out to every pitcher so there’s some room for error before any innings tax is imposed. From that point forward, for every three pitches thrown over 95 mph, the pitcher loses an inning from the initial allotment of 180. Under this rule a pitcher who makes 30ish starts can deploy three heaters that top 95 mph per outing and still throw 155 innings while averaging five-plus innings per start. Meanwhile, relievers who don’t need to worry about throwing at least 150 innings, can reach back for their high octane stuff four to six times per inning as leverage dictates, and still carry a workload of 60 to 80 innings.

The numbers guiding the rule were not chosen arbitrarily. When comparing the throwing habits of pitchers who have needed TJ to those who have not (yet) undergone the procedure, TJ-free pitchers average between 100 and 310 pitches over 95 mph per season (with relievers making up the higher end of the range since they throw less overall), while the average for those who have TJ sits between 170 and 410 pitches. Though the pitcher profiles that make up these average ranges are highly variable, the difference between the average usage of hard fastballs between those who have undergone Tommy John surgery and those who have not is statistically significant. Therefore, aiming to stay at or below the average for the non-TJ contingent provides a reasonable benchmark given the takeaways from existing research on workload and fastball usage.

As alluded to above, the rule also requires a hard cap on the number of team roster spots for pitchers. To prevent the extinction of the starting pitcher, there need to be guardrails in place to prevent teams from converting their entire staff to three-inning nonstarters as a means of still permitting them to throw hard fairly frequently. If teams can only carry 12 pitchers, as opposed to the current 13, at least a few of them need to be capable of consistently pitching deep in games. Similarly, tweaks would need to be made to the roster management protocols to prevent teams from using one roster spot as a rotating cast of DFA candidates, Jarrett Seidler and Rob Mains for Baseball Prospectus. Otherwise, it’s possible to envision teams exploiting Quad-A type pitchers to come up and absorb a handful of innings while throwing as hard as they want because they’ll be sent packing long before they reach the innings cap.

That’s the framework of the proposal, but before getting into a discussion of its merits, we should ask if it’s even reasonable for pitchers to make this type of adjustment. Some pitchers won’t need to adjust because they don’t throw 95 mph at all (hello, Ranger Suárez). Others may choose not to adjust their approach on the mound, and instead accept a smaller workload. But for starters who do throw gas and want to maintain their role as a starter, they’ll need to learn to pull back and only reach for the heat at opportune moments. How easy is it to vary speed and effort within an outing? How effective will pitchers be at less than max effort? Let’s ask the pitchers.

Justin Verlander recently told reporters that he felt pressure to change his usage as the run environment changed and other pitchers started throwing harder. “I was throwing 92-93 early in games and if I needed to go to the well and hit 100, I could [do that] late in games, but I certainly wasn’t throwing 100 every pitch.” Then around 2016 his mentality and approach changed, “The game dictated that I need to start trying to throw harder.”

When the Sunday Night Baseball crew asked Glasnow what he does to try and stay healthy, he specifically said he’s not the type to pull back and rely on his command to “Dot the corners at 92,” but he did concede that he doesn’t throw max effort on every pitch like he has in the past and incorporating secondary pitches has allowed him “to become more of a pitcher, as opposed to just a thrower.”

In 2014, Zack Greinke spoke about a self-imposed cap he put on his slider usage after noticing his elbow felt different after slider-heavy starts. His goal was to only throw the pitch 15-20 times per start as a way of managing the wear and tear on his elbow, but he also allowed the circumstances of the game dictate when he might exceed his slider quota, “In what I would deem a very important at-bat or a very important pitch, yes, I would throw the slider… If it takes eight sliders to get that guy out, I’m going to throw eight sliders.”

Clayton Kershaw’s fastball is a legend unto itself, in part because it doesn’t come with an extreme heat warning. Instead Kershaw keeps hitters off balance by delivering the pitch from the same tunnel as his slider and relying on late movement through the zone to sneak it past hitters, regardless of whether the radar gun reads 94 or 90. Shota Imanaga’s name doesn’t carry the same cachet as Clayton Kershaw, but his 92 mph fastball is effective for similar reasons. Imanaga throws a rising four-seamer that he locates at the top of the zone and pairs it with a splitter aimed at the bottom of the zone that keeps batters guessing. Michael Barker recently wrote about Kevin Gausman and Nestor Cortes as examples of pitchers who are effective at an average fastball velocity that sits 2-3 mph below their max velocity, allowing them to save that max velocity for moments in the game when they need it most. Kershaw, Imanaga, Gausman, and Cortes demonstrate that velocity isn’t the only way to win, even in a league obsessed with throwing harder and harder.

Returning to the proposed rule on the table, let’s summarize what it does and does not address. It requires pitchers to vary their velocity, as advocated by Dr. Fleisig. It does not address torque applied to the elbow when throwing other pitch types, nor does it address the increased tension stemming from flawed mechanics or pitchers attempting to improve their grip and pronation to optimize pitch shape. It also does not directly address pitch usage or workload considerations at the amateur level, but it’s reasonable to assume that whatever catches on at the pro level will influence the standards set at the amateur level, such as what we’ve seen with pitch counts.

Now, to everyone’s favorite decision making aid: the pro/con list. this approach reduces the most acute risk factors identified by experts so far, and therefore, should reduce the frequency of UCL injuries. Since this proposal does not include an immediate, in-game consequence for throwing hard, the flow of the game would not be disrupted, as it would with a ban or other mechanisms for limiting high velocity. No pitcher would be forced to change their style of pitching (though some may need to accept a reduced workload), and relatedly, no type of pitcher would be fully eliminated from the game.

Meanwhile, the rule encourages more variety in the types of pitchers capable of finding success in the big leagues. Players would spend less time competing to overpower hitters and instead spend more time mastering a wider variety of methods, such as deception, command, tunneling, and sequencing. And as pitchers creatively strategize their individual approaches, the rule would introduce a compelling element for teams as they attempt to construct and optimally deploy a pitching staff with enough bullets to last a full season.

But even with all that strategizing, pitchers as a whole are likely to lose some effectiveness. This is obviously a con for pitchers, but a pro for hitters and a league that seems keen to increase overall offense and specifically, balls in-play.

As a final entry in the pro column, the scheme presented is a concept that is simple both to track and discuss. A player’s actual innings remaining (assuming no pitches harder than 95 mph) and their projected innings remaining (based on the pitcher’s average number of pitches above 95 mph in the current season) could easily be added to a FanGraphs player page or appended to the stats graphic broadcasts display as a pitcher warms up on the mound, and announcers could feasibly keep tabs on it as the game action unfolds.

In the cons column, I must acknowledge how carefully I worded the pro argument regarding existing research. I chose the word “should” to preface the potential reduction in injuries because there is no formal testing of this specific approach, and even if a study were to begin tomorrow, it would require several years of data to determine if it’s working. The uncertainty around this proposal is the primary argument against it, and that rightfully carries a lot of weight.

I don’t have a great counter to the uncertainty argument, except to emphasize the reality of what modern pitching is doing to players’ elbows. UCL injuries are knocking great pitchers out of the game for prolonged stretches, and as a result teams are starting to treat them like paper plates rather than fine china. Something needs to change to preserve long-term player health. That doesn’t mean the league should act out of irrational desperation. It should use the best information available to create a plan for reducing risk, which is what this rule attempts to do.

But is MLB willing to make an impactful change to protect pitcher health and the broader health of the game itself? Clearly, the league is concerned about UCL injuries. Lindbergh reported that last October MLB began a comprehensive study on the topic consisting of “data analysis and approximately 100 interviews with informed figures, including doctors, trainers, independent researchers, college coaches, amateur baseball coaches and stakeholders, former pitchers, front-office members, pitching coaches, and current players.” The aforementioned Dr. Fleisig is one of the consulting experts and he told Lindbergh that the study doesn’t just aim to survey the situation; it also seeks to find and implement solutions.

Further, the league owns a prominent historical example of curbing a behavior that enhanced player performance, but came with health risks. Enforcing a ban on PEDs removed the incentive for players to subject themselves to serious side effects in order to compete at the highest level of the sport. As long as PEDs were legal, there would always be a subset of players willing to risk their health for a competitive edge, and in turn, tempt everyone else to do so too in order to keep pace. With respect to pitching, as long as George Kirby can strike out the side with a 12-pitch first inning composed of one slider and 11 fastballs all topping 97 mph, other pitchers are going to try and keep pace. (and as long as it’s permitted and he feels comfortable, Kirby should absolutely keep doing that because it rules!)

As quoted above, many pitchers feel pressured to chase velocity and risk future injury in favor of making it to the majors. They will only start to vary their speeds and find other ways to get outs if a structural change forces a collective shift in approach. As it stands, the current methods are too darn effective. The comparison to banning PEDs isn’t perfect since that change came with a guarantee to fully mitigate the associated risks. The only way to fully mitigate the risks of pitching is to outright ban pitching, and I think we all agree that’s not a viable solution. No one wants to watch Elly De La Cruz hit off a tee instead of a pitcher (though certainly it would be fun to watch him demolish line drives into the bleachers off a tee before a game). But baseball needs to do something. So let’s take a swing at what current research suggests are the riskiest aspects of pitching and be nimble enough to adjust the approach as new research comes in.

It’s worth noting that while my proposal targets those aspects of pitching that seem to come with the most injury risks, it isn’t intended to be comprehensive. Rather, mine is meant to be one possible part of a multi-pronged solution. The league’s study seems to be approaching the problem from many angles and hopefully will include things like preventative arm care, more advanced treatment methods, and the implementation of new training programs designed to help pitchers chase metrics safely. The league should also consider offering grants with no strings attached to independent researchers to assure the public that it isn’t biasing research results.

However MLB chooses to proceed, it needs to act with a sense of urgency. Because as the great philosopher Lloyd once said, “We got no aces, we got no depth, our pitchers arms are falling off!”

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