By the Numbers: Verducci Effect

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Many human decision-making flaws are being exposed by the strict adherence to the "Verducci Effect," which says that young pitchers who throw 30 more innings than in the prior year are very likely to get injured or suffer performance declines.

Major league teams are buying in, generally. Reporters are following in lock step. And even the more scientifically inclined Baseball Prospectus seems fully on board through their injury maven Will Carroll.

And why not? It sure feels like it should be true. But so did Pitcher Abuse Points (based on the number of times a pitcher exceeded a pitch-count threshold). But like PAP has proven to be after it was very unscientifically foisted upon, the Verducci Effect (named for its founder, Sports Illustrated's Tom Verducci) is likely hokum.

The main problem is that proponents have never studied it. David Gassko of the Hardball Times has done the best research to date and showed that it very definitely was not true in 2006.

Carroll says he's working on another study now. But you're supposed to test a theory before you report it, not after. To date, VE proponents are suffering from Confirmation Bias, our tendency to seek evidence for what we already believe and ignore everything else.

The parameters are currently very poorly defined. Verducci says that minor league innings count. But Carroll wrote last year that only major league innings count and this year that the VE "is about fatigue, which doesn't necessarily show up as arm problems." Carroll suggests that a decline in performance or even a loss of just one MPH on a fastball could offer proof. Also, it's not just arm troubles that prove the Verducci Effect, but the full gamut of injuries.

Shouldn't you have to hit the bullseye with a theory like this or at least the dartboard and not just the wall?

Carroll also said during an e-mail exchange with me that last year's list of pitchers is further proof of the validity of the theory. I don't see it. Not when you consider that 450 guys of all stripes were placed on the DL just last year. And not when you factor in the great research Todd Zola did as referenced in Ron Shandler's Baseball Forecaster years ago.

Zola focused on hitters, but everyone accepts that they are far more consistent from year to year than pitchers of all stripes. However, from 1996-through-2003, of all hitters who earned positive fantasy value in any year, 68 percent earned less the following year.

This is simple regression to the mean. And likely accounts for most of the VE. All pitchers being prone to injury can explain the rest.

So if you isolate any group and look for trends relating to performance decline and injury, you will find them. Remember, pitchers who pitched 30 more innings are likely pitching better and thus are more likely to regress.

Let's project the pitchers who are on the VE watch list because of their innings increase in 2008. All projections are based on market value as reflected by average draft position on


Jair Jurrjens, Braves: He's also being discounted for a regression in the second half last year. But his best K game of the year was in September and thus runs contrary to the theory that he was showing early signs of crippling strain.

Mike Pelfrey, Mets: He throws 80 percent fastballs and is so powerfully built that it's very doubtful he'll wilt after the increased 2008 workload even in the unlikely event the VE is true.

Clayton Kershaw, Dodgers: He's going cheap considering his ability because he didn't pitch well in the majors. On the 20-year-old scale, though, he pitched great. The sky is the limit.

Manny Parra, Brewers: Does the age 25 cut-off count for the prior year or the next year? Parra throwing 29 extra innings gives him the "all clear," but 33 is "Danger, Will Robinson!" Weak.

Ricky Nolasco, Marlins: The VE guys will decide if he counts later based on how he pitches. Carroll paid full value for him recently in the Tout Wars league he's in with me.


Chad Billingsley, Dodgers: He was on the list last year for 2007 and it didn't matter, so why should it now?

Zack Greinke, Royals: Actually became stronger and better as the season wore on in 2008 based on K:BB ratio. I'm ignoring the bad spring.

John Danks, White Sox: This lefty transformed into more of a ground-ball guy and also improved his K-rate as the season wore on. Thus, his chances for improving are better than average.


Jon Lester, Red Sox: There's some point where the VE would be true and maybe Lester's 70-inning increase is pushing it. Either way, he's overvalued by the experts, for sure (Shandler being the most notable exception).

Zach Duke, Pirates: Just because you walk hardly anyone doesn't mean you have great control. It could mean that you just throw a lot of fat strikes.

Cole Hamels, Phillies: VE or not, he's already having an elbow problem that's being ignored by the market. Last week his rehab fastball was in the 82-to-86 MPH range.

Michael Salfino's work has appeared in USA Today's Sports Weekly, RotoWire, dozens of newspapers nationwide and most recently throughout Comcast SportsNet, including, for which he also analyzes the Mets and Yankees. He's been writing "Baseball by the Numbers" weekly since 2005.