Under The Knife 5/27/25

Rehabbing Rehab

Paul DePodesta, the former A’s executive immortalized in Moneyball, once framed everything with what he called the Naive Question: “If we weren’t already doing it this way, is this the way we would start?” It’s a devastatingly simple challenge. It applies to baseball’s return-to-throwing protocols in the most uncomfortable way possible. Because when you look at how pitchers come back from injury, it becomes painfully clear: no, this is not the way we would start.

A new systematic review just published in Sports Health analyzed every peer-reviewed interval throwing program currently in use. These are the scripts teams rely on when a pitcher starts throwing again after a major injury — Tommy John, rotator cuff, flexor strain, doesn’t matter. They are the roadmap for return. What the review found should make anyone who works in baseball deeply uncomfortable.

Of the nine published programs, eight do not include any objective workload tracking. Not one sensor. Not one elbow torque reading. Not even a basic workload flag or biomechanical threshold. These programs are built around distance and pitch count. Thirty feet. Fifty feet. Seventy-five feet. Throw twenty-five times. Then rest. Then throw more. If there’s pain, stop. If there’s not, progress. That’s the structure. And we’ve been running with it since the early 1980s. It’s easy to say that at the time most of these protocols were published, measurements of elbow torque in real time were impossible. Exactly! Things that were great in the 80s and 90s don’t always stay great. The Go-Gos still sound good, but the cassette boombox I used to listen to them on doesn’t, at least not compared to Dolby Atmos headphones.

Most of the protocols in the study are just minor variations of the same original rehab plan developed by Axe and Konin in 1992, itself derived from even earlier non-peer-reviewed work. If that doesn’t raise your eyebrows, consider this: we have changed everything about how we understand the body since then. We measure elbow stress in real time. We have biomechanical capture down to single-digit degrees of movement using cameras. We know fatigue doesn’t come just from pitch count — it comes from pitch type, intensity, rest spacing, stress accumulation, even emotional state. Yet we’re still using protocols that amount to a coach standing behind a L-screen with a stopwatch and clipboard asking, “How’s it feel?”

The lone exception is a new protocol from Mike Reinold and colleagues in 2024. It’s the first published program to incorporate workload data and torque monitoring as part of its progression model. That alone makes it the best in class — but it also exposes the failure of the rest of the field. The bar was so low that simply measuring something made it elite. Reinold’s approach is a major step in the right direction. It respects the complexity of the elbow and the nonlinear nature of recovery. But it’s still built on a framework of fixed phase progressions and calendar-based increments. We can do better. (I’ll note here that Brittany Dowling, who I worked with at Motus, is a co-author here. Not a coincidence.)

Dr. Mike Sonne’s concept of Fatigue Units is a perfect example of what that better model looks like. Fatigue Units are a dynamic, compound metric that tracks cumulative stress over time, incorporating not just how many pitches are thrown, but what kind of pitches, how often, how recently, and how intensely. It’s a rolling measure of risk. A live readout of how close a pitcher might be to the line.

Think of it like an EKG for throwing load. Sonne’s model says that not all pitches are created equal. A high-effort slider thrown the day after a long outing is worth more — more fatigue, more risk — than a low-effort fastball in isolation. That’s how fatigue actually works. That’s how tissue damage accumulates. That’s what rehab should track. (Again, I have to note I worked with Sonne at PitchAI. He’s now with the Cubs.)

If we weren’t already doing it the old way — if we were building a return-to-throw program from scratch, right now — we’d start with sensors, not distance markers. We’d start with real-time elbow data, not stepwise pitch counts. We’d start with fatigue modeling, not subjective pain responses. And here we are, in 2025, trusting the fate of multimillion-dollar arms to 30-year-old PDFs. I’ll note as well that while this study didn’t directly assess it, these programs are largely what is being used for the various InternalBrace procedures, despite the surgery being designed to have a quicker rehab!

Ask yourself: if your team’s ace is coming back from Tommy John, do you want his rehab guided by pitch number 50 or Fatigue Unit 10.6? Do you want to guess at readiness based on the absence of pain or know it based on biomechanics and recovery curves? There’s no excuse for this anymore. The tools are here. The science is available. The money’s on the line. The only thing missing is the will to ask the Naive Question and the guts to answer it honestly.

No, this is not the way we would start. So why are we still doing it this way?

On to the injuries:

ALEX BREGMAN, 3B BOS (strained quad)

The best comparable is always the player himself. Alex Bregman had a quad strain similar to this one back in 2021 and he missed about 50 games. A similar track would put him out to July and would knock back the Red Sox as they chase the division and fight through more injuries, as well as a clubhouse that seems to be a bit out of sorts, mostly due to the way the Bregman signing has shifted the dynamics.

For Bregman, this strain is on the other side, so we’re not seeing some kind of recurrence and with four years between injuries, it’s hard to chalk this up to anything other than the occasional ability to overstress his quads. (One AT mentioned it might mean he maintains his hamstrings well, as those are normally weaker.) At age-31 and on a series of options with the Sox, he’s basically got insurance against this kind of injury. He can trigger the option, play next year, and then have another opportunity after the ‘26 season, with post-’27 and age-33 a fully open book.

In the meantime, the Sox brought up Marcelo Mayer*, who’ll get an extended look at third. I’m curious what Rafael Devers thinks about this, given his dual blowups, but Mayer playing well could shuffle things, with one of them moving to short if Trevor Story continues to struggle. With at least a month to figure it out, we’ll have to see if Mayer is an answer or just a prospect and how that changes the dynamic of a team in flux.

*In Mayer’s called-up story, there’s this whole thing about how he lost his keys and never looked for them. So how’s he getting around and what kind of car is just sitting in the WooSox parking lot even now?

RONEL BLANCO, SP HOU (inflamed elbow)

It’s no surprise that Ronel Blanco is headed out for a second opinion after being diagnosed with “elbow inflammation” and ILed. It’s almost assuredly one of the Elbow Five - the small group of surgeons that is almost always on the consult: Dr. Neal ElAttrache, Dr. Keith Meister, Dr. Jeff Dugas, Dr. Chris Ahmad and Dr. Tim Kremchek. We see this over and over, despite many of the team docs being very good and very credible. Whether it’s the players asking a teammate who did theirs or an agent who wants to have more info than the team (though it’s always shared), these “second opinions” are functionally consults.

The Astros, as yet, haven’t detailed what they’ve seen. Inflammation is a symptom, not a diagnosis. Even a mild sprain of the UCL can cause a notable response and thats same mild sprain could force the need for a surgery or we could see a similar pattern to what Jared Jones went, hoping to avoid the surgery even on the small chance of success. We should know more this week about the diagnosis and severity.

In the meantime, Ryan Gusto and Colton Gordon will hold down the back of the Astros rotation, or try. Gordon is P11 on the pre-season list and that’s the depth danger zone for most teams. Some may well have good prospects or ready depth, but most are losing quality from eight down or having to change the output plans for younger pitchers. We’ll see how the Astros braintrust will deal with this over the next few months.

Young doctors, if you want to be the next one of these, may I suggest setting up in Atlanta or Charlotte - easy access - or Phoenix. Indianapolis would be nice and as a prime medical center, I’ve always wondered why we didn’t have a top tier surgeon emerge, but I could say the same about several other cities. It’s about the surgeon, not the place.

As you’d expect, there’s more pitchers below, including more heading for Tommy John, Ohtani throwing more, and depth questions in Cleveland. Subscribers read it all.