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By Tom Verducci
February 03, 2015

Sixteen years ago, I watched 24-year-old Kevin Millwood of the Atlanta Braves get knocked out in the third inning of Game 2 of the 1999 World Series. Millwood had nothing left. His tank was empty, having thrown 79 1/3 more innings that year than ever before. The next year, he was healthy, but he was not the same pitcher who posted a 2.68 ERA in '99. His ERA swelled by nearly two full runs, to 4.66.

It was around that time I began asking Rick Peterson, then the pitching coach of the Oakland Athletics, about the pressure he faced to keep healthy his three young aces: Tim Hudson, Mark Mulder and Barry Zito. Peterson believed that as in most training disciplines, you increase workload gradually. He preferred not to increase a young pitcher's innings by more than 25 or 30 per year.

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The idea is built on a principle of exercise physiology known as SAID: Specific Adaption to Imposed Demands. The general idea is that your body will adapt to the stressors applied to it, as long as you don't overdo it. The trick is finding the sweet spot of stressors. Too little and the body doesn't reach its peak; too much and the body breaks down. Sometimes, when the stressors on a pitcher become too much, he suffers a regression the next season, which I call the Year After Effect.

Over the past decade, virtually every team has used this principle to place innings limits on young pitchers. Every year we see young, healthy pitchers shut down late in the season because they have reached their club-mandated innings limit. The most famous example involved the Nationals' Stephen Strasburg in 2012, but others in recent years also include Jordan Zimmermann, also of the Nationals (2011); Jose Fernandez of the Marlins, Jarred Cosart of the Astros and Taijuan Walker of the Mariners (2013); and Drew Smyly of the Rays, Jacob deGrom of the Mets and Jesse Hahn of the Padres (2014).

Some teams, in the wake of the notoriety Washington endured with Strasburg, have learned to build in extended periods of rest during the season for young pitchers as a way to limit their innings. The Marlins, for instance, did so with Andrew Heaney last year, a switch from the hard stop they gave Fernandez the previous year. Miami wanted to cap Heaney at about 170 innings, so they temporarily shut him down in June. He finished the year at 166 2/3, a modest 21 1/3-innings increase from his career high in 2012, including his work at Oklahoma State.

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Overall — and this caught me by surprise — pitchers in their age-25 season or younger are throwing fewer major league innings than at any time in the past nine years. The decline has been fairly steady, from 30.1 percent of all innings in 2005 to 25 percent last year. That amounts to 2,138 fewer innings by young pitchers, or the equivalent of one and a half seasons for one team.

I might have guessed that young pitchers were accounting for a greater percentage of innings, what with the bans on greenies and PEDs working against older pitchers, the usual drumbeat of complaints that pitchers are "rushed" into the majors without "paying their dues" in the minors and the call for more relievers opening doors for pitchers who need only to throw hard without developing a second or third pitch.

Instead, the 25-and-under crowd is getting less work. Why? Two related trends come to mind: the increase in Tommy John surgeries and the industry acceptance of innings limits for young pitchers.

Each year, I track the young pitchers who accumulated the greatest innings increase. This applies only to 25-and-under pitchers who appeared in the majors. The increase is measured against the pitcher's career high (in most cases, that means the previous season) and considers all innings in a calendar year (majors, minors, Arizona Fall League, college if applicable, etc.). Here are the 14 young pitchers who last year exceeded their previous high workload by at least 30 innings:

player age innings increase
Yordano Ventura 23 208 1/3 58 1/3
Rubby De La Rosa 25 161 2/3 51 1/3
Madison Bumgarner 24 270 46 2/3*
Nathan Eovaldi 24 199 2/3 45 1/3*
Marcus Stroman 23 166 1/3 43
Jesse Hahn 24 115 2/3 42 2/3
Daniel Norris 21 131 40 1/3
Stephen Strasburg 25 220 37
Anthony Ranaudo 24 177 1/3 37
Trevor Bauer 23 199 36 2/3*
Allen Webster 24 181 36*
Drew Hutchison 23 184 2/3 35 1/3*
Julio Teheran 23 221 32 2/3
Tyler Matzek 23 184 2/3 30 1/3

* Previous career high occurred prior to 2013

That's a big group. But hold on: Remember that teams use their own metrics to determine innings limits. Tampa Bay, for instance, likes to limit its young pitchers to about a 20-percent annual increase. Toronto prefers a cap of about a 30-percent increase. Percentage makes more sense to me.

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For instance, it appears at first look that Bumgarner (46 2/3 innings over his 2012 total) added more stressors than Norris (40 1/3). But when their increased load is viewed as a percentage, Bumgarner (20.1 percent) was pushed less than half as much as was Norris (44.5), to say nothing of the four-year difference in age.

So now let's look at the same group again, only re-ordering the pitchers based on their innings increase as a percentage. And using 30 percent as the redline, we get only five pitchers who went beyond most industry standards, with the rest falling out of any additional risk.

player 2014 increase
Jesse Hahn 58.4 percent
Rubby De La Rosa 46.5 percent
Daniel Norris 44.5 percent
Yordano Ventura 38.9 percent
Marcus Stroman 34.8 percent


player 2014 increase
Nathan Eovaldi 29.6 percent
Anthony Ranaudo 26.4 percent
Allen Webster 24.8 percent
Drew Hutchison 23.7 percent
Trevor Bauer 22.6 percent
Stephen Strasburg 20.2 percent
Madison Bumgarner 20.1 percent
Tyler Matzek 19.7 percent
Julio Teheran 17.3 percent


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Bumgarner told me that last December, four years after I put him on the Year After Effect watch list coming off a 2010 season in which his innings increased by 73 at age 21. Bumgarner didn't get hurt, nor did I say he would. Teams use innings limits not to predict injuries but to limit the risk of injury or regression. (Bumgarner's ERA, ERA+, WHIP and FIP all regressed slightly in 2011). Let's face it: Pitchers get hurt often. Half of all starting pitchers in the big leagues go on the disabled list every year. The innings limits are designed by clubs to avoid increasing that risk.

How did the Year After Effect play out last year? Entering the 2014 season, I red-flagged 10 young pitchers because of their innings increase in '13. Seven of the 10 regressed, throwing significantly fewer innings in the year after. Seven of those pitchers experienced health problems. Overall, the class of '14 threw an average of 39 1/3 fewer innings than they did in 2013.

Here are the 10 red-flagged pitchers from last year (it would have been eight if I used the 30 percent rule of thumb), as ranked by the greatest percentage of added innings, and what happened in their Year After:

player 2013 increase 2014 iP 2014 health
Erik Johnson 58.6 percent -40 1/3 Shoulder fatigue
Taylor Jordan 50.5 percent -85 1/3 Elbow surgery
Gerrit Cole 48.7 percent -36 Shoulder fatigue
James Paxton 42.6 percent -82 2/3 Shoulder fatigue
Danny Salazar 38.8 percent +21 2/3 Elbow inflammation
Yordano Ventura 37.2 percent +58 1/3 Healthy
Michael Wacha 34.1 percent -73 Shoulder stress fracture
Andre Rienzo 32 percent -57 2/3 Healthy
Jose Fernandez 28.9 percent -121 Tommy John surgery
Sonny Gray 28.5 percent +23 1/3 Healthy

Yes, there again is Yordano Ventura, who at the ages of 22 and 23 has packed on innings increases of 39.9 percent and 37.2 percent, respectively. The Royals tend to be one of the more liberal organizations when it comes to innings limits, and manager Ned Yost said last spring that Ventura could add 30 to 50 innings (or 20 to 33 percent) to the 150 he threw in 2013. Ventura added 58 1/3 thanks to Kansas City's playoff run. For a 6-foot righthander who throws 98 mph, he bears watching.

Here's a look at the other four pitchers who get the red flag this year, ranked in the order presented in the table above:

Jesse Hahn, RHP, Oakland Athletics

Here is your prototypical modern young pitcher and the reason why the under-25 crowd is throwing fewer innings. Hahn has already had Tommy John surgery and lived with innings limits ever since.

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After playing on the same Connecticut high school team as Matt Harvey, Hahn had that operation in 2010, the year he was drafted by Tampa Bay in the sixth round out of Virginia Tech. The elbow rehab, plus foot surgery, held him to just 121 total pro innings from 2010 to '13.

Last year, after being acquired by San Diego, the Padres placed an innings limit on him of about 110. The team worked hard to keep him in that range, first limiting his early season starts in Double A to three or four innings and then, after his promotion to the big leagues, twice sending him back to Double A to rest (with an occasional relief appearance). San Diego shut him down for good on Sept. 6; Hahn finished with 115 2/3 innings.

Hahn, who pitched very well in his 14 games for the Padres (7-4, 3.07 ERA), was traded to the A's in December and is a candidate to make Oakland's Opening Day rotation. But I wouldn't count on him making 32 starts and throwing 200 innings. He should top out at about 150 innings this year. The good news for Hahn after his 58.4 percent jump last year is that his size (6-5) and age (he turned 25 last July) leave him less susceptible to risk.

Rubby De La Rosa, RHP, Arizona Diamondbacks

Three of the 12 biggest innings jumps belong to pitchers who worked for an out-of-contention Red Sox team last year, and Boston since has traded all of them. Based on the percentage increases, though, only De La Rosa falls in the danger zone because — here we go again — he has already had Tommy John surgery. De La Rosa underwent the procedure after reaching the big leagues in 2011 at age 22. He turns 26 next month, so his new club, Arizona, should be confident that he is old enough to avoid needing any restrictions this year.

Daniel Norris, LHP, Toronto Blue Jays

Noted outdoorsman, surfer, hiker and proud owner of a 1978 Volkswagen van that sometimes doubles as his abode, Norris is, as you might have guessed, lefthanded. He's not just any southpaw, though; Norris was one of the best high school pitchers in the country when Toronto took him in the second round of the 2011 draft and convinced him to sign rather than attend Clemson.

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But here's how much baseball has changed: In his first two years of pro ball, Norris averaged only 3 2/3 innings per start. Thirty years ago, Greg Maddux, another high-school-drafted pitcher, averaged nearly seven innings per start in his first two seasons as a pro. Teams just don't let high school draftees throw very much any more.

Norris made it to the big leagues last September even though he had never thrown seven innings in any of his 60 professional starts, and in 52 of those 60 starts, he was allowed to go no more than five innings. Curt Schilling once told me pitchers are like good dogs: They will do what you train them to do. Baseball trains its pitchers to throw less.

Even in limited starts, Norris rocketed through the Toronto system. He began last season in high-A ball, reached Double A in June and Triple A in August before his promotion to the big leagues with an out-of-contention Toronto team in September. Norris and the Blue Jays soon noticed his velocity was down. One week after a season with a 44.5-percent workload increase, Norris underwent arthroscopic surgery to remove bone chips and loose bodies in his elbow.

Marcus Stroman, RHP, Toronto Blue Jays

Yes, another Blue Jay, this one a hard-throwing 5-9 righthander. He conserved some innings by spending much of May in Toronto's bullpen, but Stroman did continue to pitch through September (and well, with a 2.61 ERA in 31 innings), leading to a jump of 43 innings.

Eagle (-2)
Birdie (-1)
Bogey (+1)
Double Bogey (+2)