Do Innings Limits, Pitch Counts Actually Prevent Serious Injuries in MLB?

Zachary D. Rymer@zachrymerMLB Lead WriterApril 29, 2013

Starting pitchers in Major League Baseball were expected to be indestructible back in the day. Then, seemingly overnight, the league became aware of the fragility of starters and started to pamper them.

The tradition is ongoing. Starters don't throw as many innings these days, and every starter is on some sort of pitch count or another. But the reality is that preventing major injuries is not so simple. For all teams have done to protect their starters, major injuries are still very much a fact of life.

How did I arrive at this conclusion?

It's kind of a long story, one that consists of both my own digging around and of the digging around done by others.

Workloads Have Decreased, Major Injuries Are Still Happening

The first question I wanted to answer—as much to satisfy my own curiosity as anything else, really—was whether or not starting pitchers really have seen their workloads decrease that much.

Yeah. They have. Quite a bit, in fact.

Starting pitchers are covering a smaller percentage of innings than they did even as recently as 25 years ago. With an assist from FanGraphs' league pitching data, here's a look at the progression of the percentage of the league's total innings covered by starters since 1988.

You can see that we're not talking about a straight drop that's still progressing toward rock bottom, but starters aren't covering as many innings as they did in the late 1980s and early 1990s. 

So there's that, and we're also seeing fewer 110-pitch starts. With some help from Baseball-Reference.com, here's a look at the percentages of 110-pitch starts since 1988.

Once again, we don't have a straight line making a beeline for the bottom, but we do have a clear downward trend. Pitchers aren't crossing the 110-pitch plateau as often, as I'm sure you've noticed and/or been told by ESPN or whoever.

OK, so we've established that today's starting pitchers are a bunch of noodle-armed choir boys compared to pitchers of previous eras, but what about major injuries? 

There's a significant hurdle here, as disabled list data isn't so easy to come across. In fact, Jeff Zimmerman of FanGraphs noted in a 2011 article about starting pitcher injuries (one that we'll get back to in a second) that DL data from before 2002 basically doesn't exist.

If so, then comparing eras in terms of major injuries is either impossible or would require much more than a weekend's worth of work. Either way, a bummer.

However, one thing I did come across was a (supposedly) complete list of players who have had Tommy John surgery on BaseballHeatMaps.com. While pitcher workloads have been getting smaller, the number of Tommy John procedures has gone way up:

To clarify, we're talking about Tommy John surgeries that have been performed on all pitchers, not just starters. That word of warning aside, the trend here is still the opposite of what you'd expect given how much starters' workloads have decreased.

That there are so many Tommy Johns nowadays speaks to two realities. One, obviously, is that major elbow injuries are still occurring. But the other is that teams are more open to the surgery than ever before. For lack of a better word, MLB has embraced it.

ESPN's Tim Kurkjian noted back in 2009 that more pitchers were on the disabled list than ever before. He also noted the paradox at work: "The less they throw, the more often they get hurt."

When Zimmerman went sifting through disabled list data from 2002 to 2010, what he found was that:

The key numbers here is that 39% of all starting pitchers will end up on the DL the following season after being a starter in the league the year before. Those injuries will result in an average of 66.3 days lost per trip...

For an age with such an enlightened attitude toward starting pitchers, these are some pretty high numbers. The average days lost is particularly scary, as it goes to show that pitcher injuries tend to be major injuries.

That reality is also apparent just from comparing pitcher injury data from the past three seasons to non-pitcher injuries (Mr. Zimmerman was kind enough to put some helpful spreadsheets together).

Year Position DL Trips Avg. DL Days Surgeries
2010 Non-Pitchers 209 41.5 6
Pitchers 237 61.0 18
2011 Non-Pitchers 252 40.0 7
Pitchers 251 58.6 17
2012 Non-Pitchers 246 48.5 12
Pitchers 239 73.7 20

Again, we're not talking only starting pitchers here, but you can see that when pitchers are getting hurt, they're getting really hurt. That's really always been the case, and it's still the case in modern times even when teams are so cautious with their arms.

But when we talk about things like pitch counts and innings limits, we tend to think about them being applied to a specific group of pitchers rather than the league as a whole. These things are for youngsters more than veterans. Is the extra caution sparing them from major injuries?

Kinda. Sorta. Not really.

Young Pitchers Are a Mixed Bag

When I use the phrases "young pitchers," "pitch count" and/or "innings limit" in conjunction with one another, your mind presumably conjures memories of some notable cautionary tales.

For example, the Washington Nationals weren't able to keep Stephen Strasburg from having to go in for Tommy John surgery in 2010 even though they handled him with the utmost care. He didn't cross the 100-pitch plateau in any of his 12 major league starts that season, and he only pitched seven innings twice.

In 2011, the Seattle Mariners scaled down Michael Pineda's workload toward the end of the season. He threw his final pitch on Sept. 21 of that year, and he hasn't thrown one since.

Also in 2011, the Kansas City Royals ended Danny Duffy's season early on Sept. 6 after he had compiled just over 105 innings. After making only six starts last year, he went in for Tommy John surgery.

Then there's Joba Chamberlain. The New York Yankees' "Joba Rules" kept him from overexerting himself as a reliever in 2007, and he averaged well under 100 pitches per start in '08 and '09. The result was a pitcher who failed to live up to his talent, and Chamberlain had to go in for Tommy John surgery in 2011.

It's largely because of these cautionary tales that there's a general distrust for the notion that young pitchers should operate under pitch and/or innings limitations. The efforts all too often seem futile, so what's the point?

But I wanted to look beyond the narratives, specifically at whether low or high pitch counts for young pitchers have a tendency to lead to major injuries.

Using Baseball-Reference.com, I drew up a list of pitchers from 2000 through 2011 who A) were 25 years old or younger, B) made at least 25 starts in a season, and C) averaged 99 pitches or fewer per start in that season. One-hundred-fifty results popped up.

Once I had those 150 results, I used Baseball Prospectus' injury records and went looking for cautionary tales: pitchers who either went on the 60-day DL with a major arm or shoulder injury the next season, or who struggled with an arm/shoulder injury for a significant amount of time.

Out of 150 special cases, I counted 26 cautionary tales. Not so bad, right? But just to make sure I was being completely thorough, I went and looked for young pitchers who made 25 starts in a season while averaging at least 100 pitches per start.

Of the 145 cases that turned up, I counted 13 cautionary tales. That's half as many cautionary tales than the workload crowd provided from a sample size basically just as big.

But I don't want to suggest that keeping young pitchers on a short leash is actually more reckless than turning them loose. Simple chance could be the real explanation for the major injuries among the sub-100 crowd, and there are some notable cautionary tales that didn't make the cut for the over-100 crowd.

I didn't count Rick Ankiel, who spent much of 2001 in the minors after averaging 101 pitches per start in 2000 with the St. Louis Cardinals. But he eventually dealt with injuries in 2002 (forearm strain) and 2003 (Tommy John) and had to put his pitching career aside.

I also didn't count Mark Prior because the injury that sidelined him for much of the 2004 season was an Achilles issue, not an arm or shoulder issue. But he averaged an absurd 113 pitches per start in '03, and we all know he was never the same after that.

Then you have guys like Neftali Feliz. As reported by Jim Bowden of ESPN and SiriusXM radio, the Texas Rangers' plan was to limit Feliz to 140 to 160 innings in his first season as a starter. What they didn't do was limit his pitches, as Feliz averaged 103 pitches per start in his eight outings, topping out at 119. He eventually needed Tommy John surgery.

Feliz's arm was wrecked just last year. The 2011 season, meanwhile, produced five cautionary tales (Brandon Beachy, Zach Britton, Jaime Garcia, Dillon Gee and Michael Pineda) from the sub-100 crowd and two cautionary tales (Jhoulys Chacin and Daniel Hudson) from the over-100 crowd.

Which is distressing. This is recent history we're talking about. Given how long teams have been pampering starters, you'd expect less wreckage in recent history. This is a sign that teams haven't found the right balance yet, and that's a department where I'll turn the floor over to other voices.

What Do the Experts Have to Say on This Matter?

Way back in 1998, Rany Jazayerli of Baseball Prospectus introduced the "Pitcher Abuse Points" system—essentially based on the number of pitches thrown per start.

It was a revolutionary idea, and it happened to coincide with another revolution in MLB. Jazayerli recalled in a 2012 piece about Stephen Strasburg for Grantland that teams began to see the light in the late '90s, and the PAP system eventually became obsolete.

Later on came the kicker: "Major league baseball teams have dramatically altered the way they handle starting pitchers — and in doing so, they have significantly reduced the risk of injury to those pitchers."

There's still support for the idea that higher levels of abuse mean a higher risk of injury. Baseball Prospectus' Russell A. Carleton just penned a piece in February about injury predictors for pitchers, and the short version of it is: "You are more likely to get injured if you threw more pitches last year, and if you had an injury last year."

However, there are differing opinions on whether pitch counts and innings limits are really all that effective in terms of keeping pitchers healthy. We're starting to hear some push-back against the idea.

In 2012, sabermetrician J.C. Bradbury published the findings of a study on the effect of big pitching loads. His conclusion:

Although the belief that overuse can harm pitchers is widespread, there exists little evidence to show that the number of pitches thrown and the days of rest affect future performance and injury among adults. 

Later in 2012, Reuters Health referenced a study carried out by Thomas Karakolis, a doctor from the University of Waterloo in Canada, that concluded that teams' obsession with pitch counts and innings limits is probably misplaced.

"I don't necessarily think that pitch counts or innings pitched are the best way to measure the demands of pitching," Karakolis said.

He's not alone there. Last June, Ben Lindbergh of Baseball Prospectus spoke to Glenn Fleisig of the American Sports Medicine Institute, who is a leading expert on biomechanics. He made the following point:

The other thing is—this is a big concept that people are overlooking—the arm, the elbow, the shoulder of any of these pitchers—these are living people, they’re not pieces of metal or plastic or whatever. So you can’t just count things up. In other words, you’ve heard the analogy: people say ‘You have so many bullets, and you don’t shoot all your bullets,’ you shouldn’t always just blow it on one game or season or this or this or that. That analogy works with bullets, because if you had a case of bullets and you shot them all, you would be out. But an arm, or pitches in an arm, is not a proper analogy, because a pitcher doesn’t have a certain number of throws in his arm. That’s true because pitchers are living, breathing, and their arm is repairing. The arm is breaking down and repairing.

When Lindbergh asked Fleisig if the concept of an innings limit is too restrictive, Fleisig said yes. He said that pitch counts should be used as "guidelines" rather than "rules," and that the emphasis should be on spotting and managing fatigue rather than on counting pitches and innings.

"The rule should be that when a pitcher has arm fatigue, he should come out. So when he has arm fatigue, he should not pitch again until the fatigue is gone," said Fleisig.

When it comes to fatigue, MLB is doing things backward. There's a ton of concern about not overworking pitchers in games and throughout the course of a season, and much less concern about actually preparing pitchers to handle potentially heavy workloads.

That's something Tim Keown of ESPN.com wrote about last year:

But the emphasis on pitch counts and innings limits obscures a central fact: Pitchers are overpitched and undertrained. The reason everybody goes nutty when the White Sox allow Chris Sale to throw 115 pitches on May 28 and 119 on June 3 isn't because there's some magic number that portends weakness or injury or imminent surgery. Instead, it's because most professional pitchers aren't allowed to train their arms to throw 110-plus pitches in a game and be in a position to be strong five days later.

In a nutshell: In this day and age of pitch counts and innings limits, pitchers aren't building up enough arm strength.

Keown noted that many training programs have roots in rehab programs that only allow long toss from a maximum of 120 feet. The problem with this is that healthy arms are being treated like unhealthy arms, theoretically resulting in weaker arms.

"The pitch count became necessary to compensate for the lack of training," said long toss expert Alan Jaeger. "Once the 120 program came into being, guys were undertrained and the pitch count became a necessary evil."

There's also the matter of mechanics, which was tackled last year by Lindsay Berra for ESPN The Magazine. The gist was that MLB teams have yet to truly embrace the notion that there's actual science that can locate flaws in pitchers' mechanics and address them. Instead, many teams are content to be as unscientific about pitching as ever and to just keep counting pitches and innings.

The ideal scenario involves the best of all worlds coming together. That will happen when all pitchers have perfect mechanics and train themselves to handle heavy workloads, yet are monitored closely when they do pitch.

Long story short, there's a lot more to keeping pitchers healthy and productive than just watching pitches and innings. The league has come very far, but not yet far enough.

Note: Stats courtesy of Baseball-Reference.com unless otherwise noted.

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