The UCL Isn’t A New League. But It Is Greatly Impacting Two Older Ones.

You’ve likely been seeing the acronym UCL in sports headlines more than usual lately.  Especially if you’re a baseball fan, and even more especially if you happen to root for teams that have relied on power pitchers.   Even at this early stage of the 2024 season, we’ve already seen a rash of injuries impact many of them, some more seriously than others.

And it’s a continuing pattern that began to emerge as an issue last season as USA TODAY’s Gabe Lacques wrote this morning:

(T)he frequency with which pitchers are succumbing is now a full-blown crisis for Major League Baseball.  March and April are always spooky season for arm care, with pitchers aiming to safely ramp up for a season of velocity-driven violence, often with grim results. Shane Bieber’s imminent surgery and Atlanta ace Spencer Strider’s UCL injury were just the latest, most high-profile blows in a 13-month period that has seen 38 major league pitchers require elbow reconstruction.

And as both real-life and fantasy teams’ seasons are dealt devastating blows on an almost daily basis, the question is now becoming a full-fledged primal scream.  How and why is this happening?!?!

Many observers, most notably MLB players’ union chief Tony Clark, are immediately pointing to the introduction of the pitch clock last spring as the primary cause.  Lacques rattles off the list of notable names who are now serving as temporary pitching coaches and in-game analysts for their teams:

Jacob deGrom, the two-time Cy Young Award winner freshly signed to a $180 million contract, didn’t even make it past six April starts with the Texas Rangers before succumbing to his second elbow reconstruction. In the 13 months since, the hits haven’t stopped coming: Two-way superstar Shohei Ohtani. Reigining Cy Young Award winner Sandy Alcantara. All-Star ace Shane McClanahan and a bevy of his friends in Tampa Bay. Dominant closer Felix Bautista.

But for as much as the knee-jerk reaction has been to blame the clock for this given the timing, more nuanced observers are pointing out that this is far more a culmination to a generational shift and obsession for speed and power on the mound.  A well-researched, if unbylined, piece dropped on SPORTS ILLUSTRATED’s website points this out with illustrative conclusivicity:

This is the only fact you need to know about why pitchers are breaking down: the ulnar collateral ligament cannot withstand the torque modern pitchers are imposing on it. It’s that simple.  “Essentially the UCL is being pushed beyond what it can take,” says Glenn Fleisig, Biomechanics Research Director of the American Sports Medicine Institute, a leader in his field and a consultant to MLB. “We’ve developed a situation through mad science where we are pushing the body beyond what the ligament can handle.”

Fleisig’s team has done studies on cadavers to see just how much torque the UCL can withstand before it tears. The cadaver ligament began breaking apart even before the torque associated with an upper-90s fastball. Granted, the cadavers were not healthy athletes in their 20s, but the point, Fleisig says, “is we are going beyond what the body can withstand.”

Past the breaking point? “Exactly,” he says.

Here is the proof. I looked at all the starting pitchers from 2019-23 who averaged at least 96.5 mph with their four-seam fastball in any season in which they threw at least 600 fastballs. I came up with 21 high-velocity throwers over the past five years. Of those 21, 18 broke down with major injuries and account for at least 22 elbow surgeries. Here they are:

Starting Pitchers to Average 96.5+mph in a Season, 2019-2023 (Min. 600 4-Seamers)


That’s a lot of velocity.  A lot of talent.  A lot of money.  Getting far less return on investment than initially believed.

The debate will rage on as this becomes more prevalent.  And there are still many who are playing a wait-and-see game.  The Braves, for example, remain cautiously optimistic that Strider’s injury might not be season-ending, as NEWSWEEK’s Maren Angus-Coombs reported this morning:

Atlanta Braves starting pitcher Spencer Strider was evaluated by Dr. Keith Meister in Arlington, Texas, on Monday, according to Braves manager Brian Snitker.

On Saturday, the Braves announced that Strider’s MRI revealed damage to the ulnar collateral ligament in his right elbow. The Braves don’t plan to have an update on Strider until this weekend. While the Braves haven’t officially said that Strider has torn his UCL, when it comes to injuries like this, a sprain is considered a tear. The Braves on Sunday called Strider’s injury a “right elbow UCL sprain,” but they haven’t provided details on the extent of the damage – or whether there was a significant tear in the ligament.

But I’m someone who believes numbers don’t lie.  And whoever did do the research cited above has a pretty daunting argument that Braves fans will need to hope for more performances like the one they got from journeyman Reynaldo Lopez, who returned the somehow resurgent Mets to Earth with six shutout innings last night (before his bullpen nearly coughed up the lead he left with and barely escaped with a 6-5 nail-biter) than hope to see the likes of Strider’s 281-strikeout dominance from last season anytime soon.

And anyone who has has Rodriguez, Castillo or Ragans on their fantasy team?

Don’t say you haven’t been warned.



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