Eric Hartline - USA TODAY

The Year After Effect is the reason why teams, including the Phillies, limit young pitcher's innings

The Year After Effect is a very basic formula that helps teams determine at what point they should shut down a young pitcher. Many teams employ the theory and the Phillies are being very cautious with how many innings their young pitchers throw.

It's happening not just in the majors, but in the minors, as well. Take August 23rd at Lehigh Valley as an example. Ben Lively is the epitome of dominating. Through six innings, he's allowed division rival Scranton/Wilkes-Barre, who the IronPigs were chasing for first place in the division, just one hit and he hasn't walked a batter. The really impressive part of the outing is that through his six innings, Lively has only thrown 48 pitches, 37 of which were for strikes.

In the bottom of the fifth, Lehigh Valley gets the first run of the game to take a 1-0 lead. 

We head to the top of the sixth, and Elvis Araujo comes out of the Lehigh Valley bullpen to pitch. The first thought is, 'uh-oh, is Lively hurt?' After all, there had been a rash of injuries at the major league level and pitching injuries were on everyone's mind. Turns out that Lively is fine; not happy, but he's fine.

It's the Year After Effect.

"Obviously, he didn't want to come out," said IronPigs manager Dave Brundage. "But the plan is to limit innings on some of these guys and we're going to stick to that."

Lively's next outing wasn't as impressive, but he had allowed just two hits and one walk through six innings, striking out seven and giving up one earned run. After 87 pitches over those six innings, he was again done for the day.

It's the Year After Effect.

Also known as the Verducci Rule, after Tom Verducci, the man who came up with the formula, the Year After Effect is pretty simple. For any pitcher 25 or younger, look at the number of innings he threw in the previous season, including post-season, Arizona Fall League and winter leagues. Add 30 innings to that number and that's when teams will start to worry in the following season.

A few years ago, Baseball Prospectus tested the theory. They looked at pitchers 25 and younger, figured out the average number of injuries for pitchers who weren't under the Year After Effect and then looked at the number of injuries of pitchers 25 and younger who crossed that magical 30 inning workload increase. The results are interesting.

Basically, pitchers under the Year After Effect had an increase of arm injuries roughly 13-percent higher than those who didn't cross the 30 inning limit. Incidents of any injury were 14-percent higher. Shoulder (5-percent) and elbow (3-percent) were the obvious culprits. Somewhat surprisingly, hand injuries rose 4-percent and the highest growth in types of injuries were fingers, which rose by just under 7-percent.

Now, there are some arguments about the formula and other potential contributing factors. It should be noted, that the Baseball Prospectus study also only looked at major league numbers. The end result was that BP found that Verducci was on to something.

Ben Lively is 24-years old, so he falls under the Year After Effect. That means, that since Lively threw 143 2/3 innings in 2015, his magic number for 2016 should be 173 2/3. Between Reading and Lehigh Valley, Lively has thrown 164 2/3 innings this season. Hence, the quick hook.

Here's a look at other Phillies pitchers - majors and minors - who fall under the Year After Effect

Jerad Eickhoff (25) MLB 133 163 155
Vince Velasquez (24) MLB 89 119 129
Aaron Nola (23) MLB 187 217 111
Zach Eflin (22) MLB 132 162 132
Jake Thompson (22) MLB 133 163 149
Ben Lively (24) AAA 144 174 165
Nick Pivetta (23) AAA 130 160 139
Tom Eshelman (22) AA 147 177 115
Mark Leiter (25) AA 143 173 98
Ricardo Pinto (22) AA 145 175 146
John Richy (24) AA 137 167 109
Tyler Viza (21) AA 144 174 139

* Note that innings have been rounded-off and not all pitchers have been included. Generally, the lower the minor league level, the lower the workload, because teams tend to keep an eye on those younger pitchers all season long.

Two names on that list pop out. Aaron Nola and Zach Eflin. Both wound up on the DL this season, Nola with an elbow injury and Eflin with knee issues. Keep in mind that Eflin told reporters he's had trouble with his knees for a while, and the Year After Effect doesn't take things like that into consideration. To figure out if those two may have been bitten by the Year After Effect, let's look back at the 2014 season, compared to the 2015 season workload to see their numbers.

PITCHER 2014 IP 2014 + 30 IP 2015 ACTUAL
Aaron Nola 172 202 187
Zach Eflin 128 158 132

Neither pitcher fell under the Year After Effect. If you go back a little further though, Nola threw a total of 126 innings at LSU in 2013 and then went up to 172 innings between college and the minors in 2014. Technically, the rule only covers the following season, so take that for what it's worth.

Like it or not, numbers and theories like the Year After Effect are a part of baseball and they don't figure to be going anywhere. Like with Nola's early numbers, you can find pitchers who weren't damaged by an increase over 30 innings from one year to the next. 

One potential flaw in the formula - and it takes a better mathematician/statistician than I am to know - is whether the formula should encompass more of a percentage over workload than just a flat innings. Heck, maybe it should use pitches thrown. 

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