Edit: I bolded what I consider to be the primary reason NOT to put Worley in the 'pen - at least for now. As PhillyFriar notes, come late August/early September, it's a different story.
On the heels of another excellent Vance Worley start tonight, there will no doubt be calls for Vance Gogh to stay with the big club and move into the bullpen when Joe Blanton returns from the DL. While there is no doubt Vance could be effective out of the bullpen, and would probably be ready for a high-leverage role immediately, I posit that he should go back to Lehigh Valley until the need for a 6th starter arises again. More on why, and my thoughts on bullpen composition, after the jump:
Worley has proven himself ready to be a major-league pitcher (SSS alert) over the last two seasons, putting up a 24/9 K/BB ratio in 25 MLB innings and a 61/16 in 68 AAA innings. Projecting him out as nearly a strikeout-per-inning major leaguer would be generous considering a 4.9% swinging strike rate coming into tonight's start, but his excellent control, and strong offerings across the board (all of his pitches have positive values according to fangraphs) mean he is clearly going to be a successful big-league pitcher.
Given the mildly disheveled state of the Phillies 'pen (though stabilized with the emergence of Stutes and OFB) and the win-now nature of this team, Worley could be of some assistance in relief once his services are no longer needed in the rotation for much the same reason he is preferable to Kyle Kendrick as a starter.
However, the Phils currently have three-and-a-half relievers who are capable of getting the job done (counting JC Romero against left-handers), which is enough to get the job done most nights with our Ace Overlords starting 80% of the time. Once Jose Contreras returns from the DL, there will be ample good relief available in the bullpen despite the continued presence of Kendrick and Danys Baez. Worley would be somewhat of an unnecessary luxury at that point.
Hand-in-hand with the fact that Worley would be a luxury in the 'pen are the roster management issues associated with the Vanimal. To wit:
Assuming the Phillies do the right thing and send Vance Worley (with a firm handshake and thanks for a job well done) back to AAA when Blanton returns, what then of the bullpen?
David Herndon is back in AAA. I suspect we will not see him until September 1st. He needs the time to get some consistent innings, hone his secondary offerings and gain better control of the sinker.
Another bullpen spot should open in the next few days, as Carlos Ruiz will either return from injury (and Sardinha returned to Allentown) or be placed on the DL. Zagurski is not necessary given the return of Romero.
At AAA, prospects Scott Mathieson and Michael Schwimer are possibilities, but both have struggled with control in the early going. Lightly-regarded Chance Chapman is also in the bullpen in Allentown, with nice peripherals to boot.
At AA, winter hype favorite Justin De Fratus is struggling with control as well (though, it should be noted, for the first time in his minor-league career). However, teammates BJ Rosenberg and Phillippe Aumont (remember him?) have both rediscovered their prospect status after disastrous 2010s for each. Rosenberg currently sports a 16/3 ratio in 12.1 innings, with Aumont posting a similar 16/4 ratio in 12 innings.
Of course, veterans Drew Carpenter and Jason Grilli could find themselves in the mix as well, with Juan Perez as a good bet to see a call-up if the need for a southpaw arises.
Of the 9 listed options for the 'pen, only Mathieson and De Fratus are on the 40-man roster, which will give them preferred status if they are pitching well. My guess would be one of those two. Both have had better control in their most recent outings, and for Mathieson it's essentially now-or-never. If those two are passed over, and Schwimer hasn't cut down on the walks yet either, I think Rosenberg could get the call, as he is 25 himself and seemed a big favorite of the front office until he struggled so much last year. Aumont's probably a better option, but I could see LaMaro wanting to shield him from the bright lights of the city until he's had some time to consolidate his gains.
Assuming whoever is promoted in the coming days is sent back to the minors when the Big Truck returns (late May, early June), there will be an interesting decision if/when Brad Lidge returns: Baez or Michael Stutes?
The Phillies have shown themselves willing to cut ties with a sunk cost in the past if a better option presents itself, and Stutes is in the process of presenting himself as a big-league ready reliever right now. And it's pretty well-accepted in these parts that Danys, despite being a nice guy, blows at baseball. For that matter, so does Kendrick, but my belief is that the Phillies value his ability eat innings (NOM NOM NOM) enough to keep him around.