A piece of ligament made its way from Stephen Strasburg’s left leg to his right elbow on an operating table in Inglewood, California last month, putting a premature end to the pitcher’s exciting debut season. The impact of that operation on the intertwined futures of Strasburg, the Nationals, and the game itself have been discussed and dissected ever since his diagnosis came down, so his role in this article is nearly at an end; we won’t know much more about his prospects until continued healing and rehab hasten his return to a major-league mound.

Although Strasburg has temporarily exited the stage, a bit player in the Strasburg saga deserves another scene. Two days after Strasburg was scratched from his scheduled July 27 start with shoulder stiffness, White Sox pitching coach Don Cooper appeared on Sirius/XM’s MLB Network Radio to discuss the injury’s significance, and wasn’t coy about his feelings.

“The real concern is what I call an upside-down arm action,” Cooper said. “I am not wishing this guy bad, but for him to be having problems right now when they are really, really watching him, what are they going to see when they are trying to get 220 innings from him? He does something with his arm action that is difficult, in my mind, to pitch a whole lot of innings on.”

“It reminds me a little bit of Kerry Wood, a little bit of Mark Prior,” Cooper continued. “I hope I’m wrong about this. When you throw with the kind of talent and force that he can throw, you can break easier than let’s say a Mark Buehrle type."

Cooper added, “We watch their workloads, we have a great training staff and a great conditioning staff. Now, that Strasburg thing would really be concerning me right now. You are talking about a guy coming out of college, probably pitching on Friday nights, and now he has a major-league workload… I guarantee you throwing pitches in the major leagues is a whole lot different than throwing pitches in college. There’s physical and mental stress that goes along with every major-league pitch.”

Maybe those words shouldn’t come as a shock. As exciting as he was to watch, Strasburg had an air of “too good to be true” about him from the start; watching him mow down major-league hitters before turning 22 brought to mind Icarus’ abbreviated flight, if not Faust’s bargain, perhaps preparing us on some level for the revelation that his ligaments, at least, were mortal. Ill-fated literary figures aside, one needn’t be a savant to know that an arm injury of any sort doesn’t bode well for a young pitcher’s future, so it’s no surprise that a pitching coach would utter an on-air “uh-oh” after hearing about Strasburg’s first trip to the DL.

However, Cooper’s comments after Strasburg’s troubles were revealed to be both serious and UCL-related provided a good deal more fodder for discussion. A few days before Strasburg went under the knife, published a story entitled “Did mechanics cause Strasburg’s injury?” Most of the included quotes followed a well-established script.

“Happens,” said Rays manager Joe Maddon, one of the game’s most progressive on-field thinkers. “That’s one part of the game, regardless of how much care you take.”

“You could say you could see it coming, but you never know with arms,” said Phillies pitching coach Rich Dubee.

Orioles pitching coach Rick Kranitz took a similar tack, declaring, “All I know is this: If people say that, ‘I saw this coming,’ I think they're speaking out of turn. Because there’s just no way that that's the case.”

Dodgers head trainer Stan Conte, a man who’s devoted considerable time and energy to injury prognostication, allowed, “There are a lot of theories on mechanics, nothing proven… has anybody spotted a common thread to head it off? No. It's all to be discovered.”

Even Nolan Ryan—the picture of durability during his own playing career—helplessly conceded, “It’s just one of those unfortunate things that happen to pitchers.”

And then there was Don Cooper.

“We have a decent idea of the better-working deliveries,” Cooper claimed. “Our pitching coaches and our trainers and our conditioning guys take good care of them. We are able to make adjustments to deliveries we feel might be threatening to health. Everybody says you can't prevent (injuries). Listen, I differ with a lot of people with what they are saying. I'm not going to go into the Strasburg thing, but there are things you can do. I'm not going to say what they are. I believe we have a pretty good handle on them."

Considering that most of the game’s finest minds regard injury prevention as mostly uncharted territory, experimenting with biomechanical analysis or reevaluating their training techniques in an attempt to harness hitherto untapped potential, Cooper’s self-assuredness strikes a discordant tone. Unlike other baseball luminaries who chose the occasion to weigh in via satellite radio, Cooper might possess the pedigree to form an informed opinion. But do Cooper and his cohorts really hold the secret (or some of the secrets) to preventing pitcher injuries? The proof is in the pitching—or, at least, it should be. If Cooper and his support staff truly “have a pretty good handle” on injury prevention, their success should show up in the medical record.

Fortunately, we have one such medical record lying around. As Colin Wyers revealed recently, we’ve been working on optimizing a comprehensive injury database for incorporation into PECOTA. That database’s records extend back through 2002, which conveniently happens to have been Cooper’s first season with the White Sox. So what do the data tell us about Cooper’s moundside manner? The following images reveal how the White Sox have stacked up against the other MLB teams in the pitcher injury department over the past nine seasons. A couple quick notes—if a player didn’t appear during a given season as a result of injury, he won’t show up in this accounting; secondly, since these displays don’t account for the quality of the fallen players, they don’t present a completely accurate picture of lost value.

Well, that’s a dramatic difference. The White Sox have more or less lapped the field when it comes to pitching injuries, suffering by far the fewest DL trips taken and DL days lost over the past almost-decade. Sustained health confers enormous benefits upon a baseball team’s fortunes, both on off and on the field: by keeping their first-string pitchers healthy, the White Sox have managed to save millions, while steering clear of the subpar second- and third-stringers who can so often derail a team’s playoff hopes. Eschewing the need for replacements is the surest way to avoid replacement-level (or sub-replacement) performance; just ask—rhetorically—the 2005 edition of the team, which used only six starting pitchers over the course of its World Series-winning campaign.

Of course, it’s difficult to apportion credit here. We can’t say, with any degree of certainty, that the White Sox have learned how to prevent pitching injuries; perhaps they’ve simply learned to avert them, by identifying the pitchers most likely to suffer them and then avoiding those marked men like the plague. Still, either achievement would represent a significant addition to the sum of baseball knowledge, and could help to explain why the White Sox have occasionally constituted a blind spot for PECOTA.

However, even if the White Sox have cracked a crucial sequence of the pitching injury code, we might not want to christen Cooper the league’s Most Valuable Pitching Coach just yet. Check out how the team’s non-pitchers have done in the injury department:

It would seem that White Sox pitchers aren’t the only South Siders with adamantium-laced skeletal structures—Chicago’s position players have also managed to avoid the DL with impressive regularity, though not to quite the same uncanny degree. Since Cooper likely has little to do with keeping position players active, someone else might be responsible for the effect we’re seeing here. Should we credit Kenny Williams with acquiring low-risk talent? Or Ozzie Guillen for not pushing his players beyond their breaking points? And how about 2006 Dick Martin Award winner Herm Schneider and his support staff?

If Schneider has the magic touch, he must be among the most valuable non-players in the game; the head trainer has served the Sox in that capacity since 1979, but since our records go no further than 2002, we can’t check to see whether the long-tenured Schneider’s success predates Cooper’s arrival. For what it’s worth, pitcher DL days and position player DL days were weakly correlated at the team level during the 2002-10 period, with an r of .32, though that could reflect common approaches to injury treatment more so than similar incidences of injury occurrence.

Cooper clearly isn’t about to divulge any specifics, thereby surrendering what appears to be a commanding competitive advantage (though Schneider has divulged aspects of his training program in the past), so we’re left to mine his words for hidden meaning. The pitching coach did claim to be able to “make adjustments to deliveries” in order to promote healthy pitching, but he also alluded to “Mark Buehrle types” who allegedly derive health benefits from throwing with less force. It’s unclear what Cooper meant by “Mark Buehrle types,” since any number of traits could characterize Mark Buehrle, including his impressive durability itself (the lefty has strung together 10 consecutive seasons of 200+ innings pitched). If he meant that pitchers who throw harder are more susceptible to injuries—well, that’s something we can check. If he was referring not to Buehrle’s velocity, but to the pitcher’s clean-looking delivery, his contention would be more difficult to verify.

Limiting oneself to lower-ceilinged pitchers has the potential to place a similar ceiling on one’s on-field results, but if those pitchers can keep themselves on the field, saving their teams the trouble of employing underachieving also-rans through the season, they could prove to be the more valuable bunch: League-Average Innings Munchers have value (and above-average innings munchers like Buehrle have even more). It’s worth noting that the Sox haven’t been staffed by a notable number of soft throwers or pitchers reliant on less stressful straight stuff in recent years. Nor have they challenged any child labor laws; in fact, on both sides of the ball, recent White Sox squads have tended to skew toward older players, whom we generally classify as more susceptible to injury.

 Assuming that the organization hasn’t simply been the beneficiary of a run of good luck, there could be significant value in mimicking the White Sox Way when it comes to handling players, especially the fragile ones who make their living on the mound. We’ve seen the results—they’re real, and they’re spectacular. Now we just have to figure out where they came from. Until we—or their MLB competitors—succeed in catching onto their methods completely, it might be wise to continue the investigation into how the White Sox have gotten the most out of their rosters, simply by keeping them intact.  

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Very interesting article. If Cooper really does have a key to prevent pitching injuries, he's worth his weight in gold.
This kind of touches on another issue, how knowledge in baseball is spread, and how quantitative methods can improve that. when people can actually be shown results of distinct approaches in numbers and actually identify who's doing it better with more clarity, they'll be motivated to do something and learn from the best.
Ben - Let me know if BP would be interested in the 2001 DL numbers. I will hopefully have them available later this winter.
Incredible how the Rangers appear to have lapped the field in the other direction. Any hypothesis there?
It would be really interesting to take this one step further. If we could "throw out" the non-pitching arm injuries and then reconsider, we might get an even better picture. For example, if a pitcher gets beaned in the head by a comebacker and misses two months, that has nothing to do with his arm or mechanics (except for perhaps finishing in a position where he's less likely to be able to field said comebacker). This type of injury should be excluded. Similarly, to the extent that we could say things like oblique strains and hamstring problems don't have to do with pitching arm mechanics (perhaps a slippery slope...where do we draw the line?), those types of injuries can be removed also. Once we isolate pitching arm injuries, I wonder how the results would look. Obviously, this would require much more extensive research.
Well, if we 'can check whether harder-throwing pitchers have more arm injuries', what do results show?
It may not be actual injury, but Sox pitchers wear down. Take a look at the performance in the last 6 weeks of a season.
You might have to separate those tallies to account for pitchers developed by their respective systems and those that were signed as free agents and presumably finished products as far as mechanics go. Players acquired by trade might fall into either bin depending on their career status.

Dividing the player pool up in this manner might separate organizational ability (teaching good mechanics to young pitchers) from trainer skill (keeping pitchers taught under different systems healthy). A third possibility is none of the above, the capacity of management and scouting to correctly identify those pitchers who are inherently low-risk and largely immune to developmental or training factors.

To be really comprehensive, prospects lost to injury by an organization may have to be added to the pool in order to avoid survivor effects.