Ever since it became clear a few months into the 2011 season that Vance Worley was going to be sticking around for a while, the more sabermetrically inclined sectors of Phillies fandom have gone to great lengths to explain who Worley is not -- namely, he is not the next edition of 2007 Kyle Kendrick or 2009 J.A. Happ. Even though Worley's rookie-year ERA certainly benefited from a low-ish .283 BABIP and 7.2% HR/FB, his peripherals were much better than those of his predecessors and so, his chances of maintaining his success going forward are much greater than theirs were. The numbers clearly back this up:
But enough about who Worley isn't. What we really want to know is who Worley is. And that's a really tough question to answer, as Worley is one of the most difficult guys on the whole team to project.
A brief history: Because 2007 third-round pick Brandon Workman had elected not to sign and because Aaron Rowand had left in free agency over the following winter, the Phillies found themselves in June 2008 with two first-round picks, two second-round picks, and two third-round picks. They responded by implementing a high-risk/high-reward draft strategy, going (almost) all-in on a number of very raw, talented high school players: Anthony Hewitt, Zach Collier, Jason Knapp, Anthony Gose, and Jonathan Pettibone (though Collier and Pettibone were considered to be a bit less raw). They also picked current top prospect Trevor May in the fourth round.
The only exception to that strategy was Worley, a 20-year-old from Long Beach State University. I have a vague recollection that most people were disappointed with the pick at the time, feeling that it was an overcorrection to the ultra-risky picks that had preceded it. Worley was too far in the other direction -- he wasn't risky, but his ceiling was just too low, not unlike his former college teammate, Drew Carpenter, whom the Phillies had drafted two years earlier.
Worley signed quickly, was promoted to Lakewood almost immediately, and performed well for the rest of the year. Still, he barely made a dent in any of the Phillies' prospect rankings that offseason. The Phillies surprisingly double-jumped him out of the following spring to Reading, where he got off to good start, then hit a wall over the summer, and limped to a 5.34 ERA (4.39 FIP). But he rebounded well in 2010, posting very strong if unspectacular numbers, which earned him a promotion to Lehigh Valley in August and a cup of coffee with the big club in September. He opened 2011 in seventh place on the Phillies' SP depth chart.
By this time, his standing with prospect experts had improved. But still, nobody thought he had a chance to be anything really special. SBN's own John Sickels wrote on January 1, 2011:
9) Vance Worley, RHP, Grade C+: Should be a competent fourth starter. Doesn't have the ceiling of some of the guys below, but a much safer bet to make it.
And then last year happened. In sum, he was a whole lot better than a "competent fourth starter" in 2011. He was plugged into the rotation after injuries felled Joe Blanton and Roy Oswalt, and posted a great ERA from day one. His peripherals were relatively unimpressive at first, but as the season wore on, it was his peripherals, not his ERA, that changed. His xFIP over the last three months of 2011 was in the 3.3s, and his end-of-year xFIP of 3.66 ranked him 26th out of the 75 NL pitchers who pitched at least 100 innings. Meaning that mathematically, he performed at the level of a #2 starter.
And that was at age 23. Most 23-year-olds have room for improvement. If Worley was a 3.66 pitcher at that age, how good will he be at age 24, or 26, or 28? Could he be a future ace?
Maybe, but there are good reasons to hold our horses. If Worley is really this good, how come he never showed it in the minors? His MLB K rate is better than his AAA, AA, or A-Ball K rates! Isn't the likeliest explanation that he just got hot and pitched over his head for three months? Even though Worley's 2011 peripherals were superior to 2007 Kendrick's or 2009 Happ's, those two precedents should still give us pause. Those two guys didn't just regress to their rookie-year DIPS in later seasons. Their DIPS also got worse. Happ's rookie-year ERA, for instance, may have been luck-inflated, but his luck-neutral performance was still perfectly competent: a 106 xFIP- is nothing to sneeze at, especially for a cost-controlled pitcher. His problems since then haven't so much resulted from a regression to the mean as from a downward spiral of the mean.
But on the other hand, what if Worley's 2011 was legit? What if the explanation for his unexpected performance level was that he just got better? It's not as if he'd be the first late(-ish) bloomer in MLB history. Anecdotally, it was said that his performance took off in the second half after a bullpen session in which Brian Schneider noticed good movement on Worley's two-seam fastball. Worley, the theory goes, then started throwing the two-seamer a lot more and got tons of called third strikes with it. Certain aspects of that theory are difficult to verify since we can't really look up Worley's pitch selection in the minors. But there's no doubt that as a rookie in MLB, Worley threw a heckuva lot of two-seamers and got a heckuva lot of called third strikes. (In fact, his backward-K rate in 2011 was historically high.)
Kendrick's example is kind of a double-edged sword in this regard. As I wrote in my article on Kendrick last October, every once in a blue moon a pitcher will alter his pitch repertoire to such a degree that it destroys the predictive value of his past statistics. There is a possibility that Kendrick, by mastering the cut fastball, turned himself into an entirely new man, one with little resemblance to the guy who wore "38" on his back from 2007 until last August. Maybe the same kind of thing happened with Worley and his two-seam fastball.
So, which theory is the right one? Was Worley's rookie season flukish (albeit less flukish than Kendrick's or Happ's)? Or is he on a meteoric trajectory? Your guess is as good as mine. All I can say is that for 2012, I'll be satisfied with any performance level from him that's within spitting distance of the league average. And I feel pretty confident that we'll get that at the very least.