“It's like training for a marathon. You need to build stamina incrementally. The unofficial industry standard is that no young pitcher should throw more than 30 more innings than he did the previous season. It's a general rule of thumb, and one I've been tracking for about a decade. When teams violate the incremental safeguard, it's amazing how often they pay for it.”

So wrote Tom Verducci last February, illustrating what he called the “Year After Effect,” but has since gained popularity as the “Verducci Effect.” Let’s start by looking at the seven players that Verducci identified as being particularly risky for the 2008 season, and then let’s try to identify some risky players for 2009.

Here are the pitchers that Tom Verducci listed as being possible victims of the so-called Verducci Effect in 2008:

Ian Kennedy
Fausto Carmona
Ubaldo Jimenez
Tom Gorzelanny
Dustin McGowan
Chad Gaudin
Yovani Gallardo

Wow – pretty convincing evidence for this theory. Kennedy was awful at the major league level; Carmona was hurt for much of the year and ineffective when healthy; Gorzelanny’s ERA went up nearly three full runs; Gallardo got hurt and missed most of the season (although this is unfair, as his injury was a fluke unrelated to his shoulder or arm).

Jimenez defied the Verducci Effect, pitching nearly 200 innings and showing tremendous improvement. Gaudin pitched primarily out of the bullpen and maintained his production. However, five of the seven players that Verducci identified as being particularly risky were either hurt or very ineffective in 2008.

Of course, caveats abound: there is no control study, and we know that pitchers – especially those under 25 – are inherently risky, not just pitchers who have had big innings increases. Furthermore, this is a very selective sample: in order to accumulate a large increase in innings, you have to be pretty effective – perhaps even more effective than your “true ability,” thus making regression more likely. Still, the results are convincing, and Verducci writes of similar results from past seasons as well.

So what about 2009? Well, we can identify seven pitchers once again who may be at increased risk due to the so-called Verducci Effect.

Jon Lester (162 IP last year, 237 this year – 76 inning increase). Lester’s situation is certainly unique: he has progressed nicely in his recovery from cancer, and seemed to gain strength as the season progressed. I’d subjectively guess that Lester is less likely to be effected by the innings increase than another pitcher, simply due to Lester’s conditioning program that allowed him to re-gain his strength (and then some) after cancer. I have also full faith in the Red Sox’s ability to handle him appropriately. Still, a 76 inning increase is enormous, and probably makes Lester a risk.

Cole Hamels (190 IP last year, 262 this year – 72 inning increase). Hamels pitched 35 innings in the postseason this year after 227 regular season innings. Hamels had shed his tag of being injury prone, but he’s still only 24 years old, and a 72 inning increase is huge.

Chad Billingsley (147 IP last year, 212 this year – 65 inning increase). Billingsley’s innings have been steadily increased for several years now, but a 65 inning increase is enormous. Billingsley is big and athletic and has no history of injury, but it still a risk for 2009.

John Danks (139 IP last year, 195 this year -56 inning increase) – Danks was very effective in 2008, thanks in no small part to the introduction of the patented Cooper Cutter. However, he also saw a huge jump in his innings pitched, leading him to be pretty risky for next season.

Mike Pelfrey (146 IP last year, 200 this year – 54 inning increase). Pelfrey is a prime candidate to be a victim of the Verducci Effect. I can’t fault the Mets for the way they used him in 2008, since they were in a heated playoff race and Pelfrey was very effective. However, he threw many more innings than he ever had, making it fairly likely that Pelfrey will experience an injury and/or ineffectiveness in 2009. It’s far from a certainty, but if I was a Mets fan, I’d be very worried.

Tim Lincecum (177 IP last year, 226 this year – 49 inning increase). Yes, we all understand that Lincecum is a freak of nature – even by major league pitchers’ standards. Still, a 49 inning increase is nothing to sneeze at, especially in a young pitcher. I personally think he’s likely to be effective once again in 2009, but the innings increase is noteworthy nonetheless.

Jair Jurrjens (142 IP last year, 188 this year – 46 inning increase). Jurrjens’s innings increase isn’t quite as large as some of the other players on this list, but it still well exceeds the 30-IP threshold. Although he was a pleasant surprise for the Braves in 2008, Jurrjens may experience injury and/or regression in 2009.