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Strasburg Should Get More Starts

Stephen Strasburg got shut down for the year. He is the best pitcher on arguably the best team in baseball. A legitimate World Series contender just shut down their ace for the season. It miserably fails the "eye test" as a good decision. Add me to the chorus of silly and unfounded complainers.

I have two overarching issues with how the Nationals handled Strasburg this season, one more deeper and fundamental than the other.

I'll start with the easier issue to handle. Clearly, the Nationals knew they were going to limit Strasburg's innings at the start of the season. They also got off to a hot start, one that suggested very early on they just might contend. So why didn't the Nationals space Strasburg's innings out so that he would have been available in September and October?

Strasburg made 28 starts this season. Here are some other ways those starts could have been spread differently:

1. Strasburg makes one start a week all season. Say he is the Friday starter. The Nationals have/had 25 games on Fridays this year. Strasburg could have started every one of those and still had 3 more starts to make in the postseason. He could pitch once in the NLDS, twice in the NLCS, and then the Nationals would only risk over-exerting him in the World Series, and even then by only 10-15 innings. This plan might have required a six-man starting rotation, but with off days I think the sixth starter could also be an emergency long reliever.

2. The rotation could have been creatively mixed around the All-Star break. Let's say Strasburg starts Tuesday before the All-Star break. His next turn would have been the first day of the break. Let's say coming out of the break he pitches last in turn. That would have fallen on Tuesday, July 17, a full two weeks after his previous start. This could have been done without calling up any spot starters. This would have played almost like skipping Strasburg twice in the rotation without forcing anyone else to start on short rest. A starter will take the mound 32-33 times a season if their turn is never skipped. This move alone would move Strasburg down to 30-31 projected starts. Again, the magic number was apparently 28. That means the Nationals would have only had to find 2 or 3 other spots the entire season to skip Strasburg to make it to the end of the season. This could be done in September easily with September call-ups. Start spots are not a roster-crunch issue.

3. Make Strasburg a reliever after the All-Star break. That would have naturally limited his innings. He could be ramped back up to a starting role in September when rosters expand. His first few starts would be short, but he wouldn't burn the bullpen because they would have extra arms available.

My main point is that there were several ways to stretch out Strasburg's limit so that he could pitch all the way through the end of the season. Some would have taken more planning ahead than others. However, the constraints were known before the season began. Maybe the Nationals  didn't expect to be so good, but even their ability showed itself very early in the season.

It is entirely fair to criticize Washington. This isn't a case of "well if we had known then what we knew now..." The Nationals knew, and this is how they chose to play the situation. It is unconscionable to me that the Nationals did not find a way to limit Strasburg that did not involve benching him for the remainder of the season.

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There is a deeper argument that I'd rather make though. Why, exactly, is limiting Strasburg's innings such a good idea? What follows is my attempt, via the power of the internets (always a dangerous power to use), to understand the rationale.

Stephen Strasburg is coming off of Tommy John surgery. Tommy John surgery, in more official terms, is ulnar collateral ligament (UCL) reconstruction. Essentially, Strasburg snapped the ligament in his pitching elbow, and so a doctor slapped a new one on. Grafted is the more official term for slapped, in case you were wondering.

Therefore, getting back to the inning limit, the justification for shutting down Strasburg has to come back to the injury risk for the UCL. There has to be a good reason that throwing fewer innings decreases the risk of re-injuring the UCL.

So, the next logical thing to investigate is just how the UCL gets injured through pitching.

Ligaments are fibrous tissues that connect bones. Their primary role is to stabilize the skeletal structure. Ligaments are like pieces of scotch tape that keep bones from flying wherever they may please. If you've ever tried to rip pieces of paper apart that are taped, you've probably realized that it is easier to rip it apart by pulling perpendicular to the way the papers fold. This is the same with ligaments, If you watch football, most ACL tears happen when legs (particularly around the knee) bend sideways suddenly; back-and-forth motions like how we walk are generally fine.

The other way to tear tape apart is to simply pull on either side so hard that it gives way. This takes quite a bit more force, but it turns out that this is basically how a UCL frays and/or tears in a pitcher's elbow. I've been reading through a little book called The Physics of Baseball by Robert K. Adair, and he says the following about throwing a baseball hard:
In this estimate, we consider a pitcher throwing a major league fast ball so that it leaves his hand with an initial velocity of 97 mph to cross the play 0.4 seconds later with a velocity of 90 mph...With these numbers, we find that the average power the pitcher transmits to the ball in the course of the pitch is about 1.5 horsepower! Since the pitcher's body is also put into motion by the contraction of his muscles (in fact, his hand and wrist are moving nearly as fast as the ball when it is released), we conclude that his musculature must have generated energy at a rate exceeding 3 horsepower during the action of throwing. Such power can only be generated by the large muscles of the thighs and thorax. (Adair, 1990, pg. 39-40)
The implication is clear: the thighs and thorax (a.k.a. "the core") is responsible for most of a pitcher's velocity, not the arm. Therefore, the energy created in the core must be transfered to the ball through the shoulder and arm. Much of the 3+ horsepower generated travels through the UCL pretty much all at once, a significant force for a bundle of fibers to take on. Obviously, forces are even greater for pitchers who throw harder, and Strasburg certainly falls in the "throws harder" group.

Ultimately, thinking about what happens in slow motion,* the UCL first compresses when the energy hits it, then releases the energy up the arm, and then stretches as the whole forearm lurches forward, and ultimately pulls the forearm back in place. The UCL acts like a spring - contracting, expanding, and then contracting back to normal. The UCL does not provide any power itself. Its job is to transfer energy, and its ability to do that successfully over and over is tied directly to its ability to expand and then contract back to its original shape. The official word for this ability is elasticity.

*Disclaimer: I am no expert on how the body works. If somebody who reads this blog is an expert, please comment if I am wrong. I don't think I'm too far off, but maybe I don't know enough to know what I don't know, if you know what I'm trying to say.

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A pitcher's UCL has to be strong, no doubt, but not strong in the way that the term usually implies. Really, a UCL needs to be highly elastic. A weak UCL will gradually warp as pitches are thrown. It won't fully contract back to its original shape, and the stretching makes it more prone to tears.

Therefore, as we continue to dig deeper into this question of shutting Stephen Strasburg down, our new question is really what impacts UCL elasticity. It is rather clear that pitching stresses the UCL and opens it up to more injuries than, say, writing a letter or typing an e-mail. Therein lies the rationale for shutting Strasburg down. Pitching by nature stresses the UCL, and fewer pitches means fewer chances for the UCL to stretch and tear.

However, as I scanned the internets for elasticity-building exercises, I found several interesting tidbits. Muscle tone plays a surprising role in elasticity, because stronger muscles naturally contract more. This forces ligaments to naturally stretch more, which actually makes ligaments easier to injure. Elasticity also naturally wears down with age, regardless of use. Elasticity deteriorates if it isn't used much either - in other words, someone (like a pitcher) must use the elasticity they have built up (by doing something like pitching) to maintain it. Otherwise, it withers away, much like muscle mass goes away from arms and legs when they are immobilized for extended periods of time.

Pitching is an elastic paradox. Arm strength is theoretically important, but stronger arms are more susceptible to ligament injuries. Pitching also looks like the kind of exercise that would naturally build elasticity, yet at the same time it exerts the kind of force that can destroy it.

Hidden underneath all these issues are genetics, which appear to play a role. It seems likely that some people have ligaments more predisposed to elasticity than others. This might be one reason that Nolan Ryan maintained his velocity so late into his 40s, and that Roger Clemens topped out at 88 mph in his most recent Skeeters start.

Now, I am far from a biomechanics expert, so maybe I am missing some very important details. Tommy John surgery looks to me like a simple procedure to understand, but it has a very complex recovery. There are a myriad of factors that impact a pitcher's ability to bounce back from the operation. Furthermore, some factors seem to diametrically oppose each other. Benching Strasburg could be better for his health. Pitching Strasburg could be better for his health. I don't see how anyone could really know.

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I will say this though: if limiting workloads is a good idea, we should see some sort of evidence across the league that it is preventing injuries. We live in the most specialized pitching era in MLB history. Set-up men are making All-Star teams these days, which says something about just how important bullpens have become. We haven't seen the volume of pitchers with smaller workloads like this ever before in baseball. Wouldn't it follow then that we should live in an era where pitching injuries have dropped if innings really are an issue?

However, as Tom Verducci wrote about at the start of this season, the evidence simply isn't there. If anything pitchers are getting injure more often than they used to, despite all the modern advancements in medicine, training, and nutrition (not to mention the explosion of player salaries that gives pros the access to any sort of training they desire). There might be strategic reasons to keep micro-managing pitching staffs, but there is no reason to think it helps pitchers stay healthy.

I'm not entirely sure what all this rambling rant of mine says, other than I am dead certain that MLB teams are thinking about pitching methods in largely horrible ways. The Nationals have not been forthright with the medical evidence that Strasburg should be shut down because there isn't any. There are arguments that can be made, but nothing that's so compelling that the Nats decision can't be questioned.

This isn't a problem limited to Stephen Strasburg. Teams across baseball limit their pitchers in the name of saving their arms. Ironically, Tom Verducci did a study of pitcher workloads a few years ago that gave rise to the "Verducci Effect," an idea that great increased workloads from one year to the next opens up young pitchers to ineffectiveness and injury. However, it should be noted that some sabermetricians have taken a closer look at the Verducci Effect and can't find evidence that suggests it exists.

I see medical research that suggests pitching could both help and hurt ligament health. Disabled list data suggests that limiting innings does nothing to change pitcher injury rates. Increased workloads don't seem to say much about future pitching performances either.

What does this all have to say about Stephen Strasburg and the Nats decision to shut him down? Not much - and that's my point. The data and evidence we have at our fingertips suggests that nobody really understands what increases injury risks for pitchers.** All we know is that lots of pitchers get hurt, and they hurt their arms more frequently and severely than the general population.

** I'll admit this is a bit of an overstatement. There is probably something to pitch counts, as this longform article on Grantland about Strasburg suggests. I'm not sold on the strict pitch counts many teams use these days though.

What exactly are the Nationals accomplishing by shutting Strasburg down? Nobody can argue that his injury risk went down, but I would argue that pitching in general is risky. I am not convinced that the next few months were going to tack on much, if any, additional risk above what simply exists when a person decides to pitch competitively.

There will be a day where the human body is understood much better and teams will understand injury risks with much more precision than we do now. That's just the trajectory of medical knowledge. It would not surprise me if the Nats decision to shut down Strasburg becomes a symbol for the ignorance of this time. It might feel good to "play it safe" with Strasburg in today's baseball culture, but I would want some sound reasoning before I shut down my star pitcher in the heart of a pennant chase. There is none to be found.