A Few Starter-Reliever Conversions
.
Cases For and Against
In baseball history, you could find dozens of RP-SP conversions that worked, and dozens that didn't. Run your little "study" :- ) and you're going to wind up concluding this: All you can do is try it, and see how it works for this guy.
(Nate Silver studies 100x of the SP-to-RP, not RP-to-SP, conversions here. He opines, from a statistical viewpoint, that you want "wild" pitchers to walk people in the bullpen, but he isn't asking whether a guy like Wilhelmsen might find a starter's rhythm in longer stints.)
.
Nope
Rick Aguilera was a star closer who tried the rotation, wasn't good at it, and, um... simply moved back to the pen.
Daniel Bard had a shattering psychological experience in the rotation, one that resonated throughout the Sox org. That is a horror scenario for you.
Neftali Feliz started out fine in the rotation, but got hurt. Of course, Feliz might have been headed toward the DL in any case.
Danny Graves is my idea of a perfect case-against. He was a tremendous Scot Shields-type reliever for the Reds, threw 80-100 excellent innings a year ... hit the rotation and was a bug on a windshield, 4-15 with a 5.33 ERA.
You could find plenty more. Braden Looper, maybe? Brian Tallet? I vaguely remember them having issues, but could be wrong.
.
Yep
Alexi Ogando was overpowering in the 'pen, switched to the rotation, and was ... overpowering. He's 17-11, 3.43 lifetime in the rotation; his last start, Friday, he beat Oakland 5-3.
Chris Sale became a big star in the rotation. Imagine if the Sox hadn't had the guts to try it.
Jeff Samardzija has 180 strikeouts in 174 innings for the Cubs this year.
You might not evern remember that C.J. Wilson was a bullpen conversion, so natural is he in the rotation. (Wilson got rocked hard as a starter early in his minors career, and needed some big league time before he finally settled in as a starter. Compare Wilson's arc to Wilhelmsen's.)
In fact, now that you mention it ... Jeff Fassero was like that. Tons of guys were "surprises" who were brought up to the bigs, pitched great, and then "promoted" to the rotation like Fassero was. I'll bet there are any number of SP stars who were "promoted" out of the pen and we wind up forgetting that they came up as relievers.
eeeeYup ... Ryan Dempster had a rocky start as a young rotation guy, was 1-5, 7.08 in his first ML trial there. He established himself for several years as a reliever... he went back to the rotation at the age of 31 and won 17 games, finishing 6th in the Cy Young. A lot of times pitchers fail their first few times in the rotation, and then they get better as pitchers, and then they star in the rotation.
I wasn't even aware that Jonathan Sanchez came up as a reliever.
Justin Duscherer was an okay minors starter, was brought up to relieve, and then at the age of 30 converted to the rotation. He ripped off a 2.54 ERA in his first season there.
Some guys need a few false starts, and then they mature, and they get so good that you forget they ever had problems. Would Wilhelmsen be one of these? Dr. D would certainly be interested to find out. Why would you want to go into spring training next year without half-a-dozen games to go on?