Should Alfredo Aceves Start for the Boston Red Sox in 2012?

If it weren't for Tommy John surgery, the Boston Red Sox would already have their rotation set. With Jon Lester, Josh Becket, Clay Buchholz, Daisuke Matsuzaka and John Lackey, the Sox would have four very good pitchers, and a John Lackey.

Unfortunately (or not, as the case may be), surgery has sidelined Dice-K at least until the All-Star break, and Lackey will miss the entire season. This has provided former setup man Daniel Bard the perfect opportunity to move from the bullpen to the rotation, where he pitched in the minors. But it has left a question mark over who should be the fifth starter behind him.

The primary candidates are Alfredo Aceves and the newly-signed Vicente Padilla, with the former the preseason favourite to get the job. Felix Doubront, Aaron Cook and Andrew Miller have an outside chance.

The argument for Aceves is the most convincing, as he is the only one of the five to be coming off a good and injury-free 2011. However, even he has serious drawbacks.

His great performance last year might be his best argument for a place in the rotation, but it is also the main reason he should stay in the bullpen. Aceves pitched to a 2.61 ERA, but his numbers as a starter were much worse than those out of the bullpen. In relief, his ERA was a brilliant 2.03, but in starts that grew to 5.14.

However, he switched between starting and relieving often during the season, so perhaps a longer stint in the rotation would allow him to settle into a groove. His versatility was his greatest strength, but manager Terry Francona was loathe to move him into a starting role when he could avoid it, valuing more his contributions as a reliever.

Of course, this was in large part due to the fact that the likes of Lackey, Eric Bedard and Kyle Weiland would often be done by the fourth inning, and Boston needed a long innings man. That raises another issue, though.

In recent years, veteran knuckleballer Tim Wakefield had been used increasingly as the mop-up guy. He retired this offseason. Moving Aceves to the rotation leaves that role vacant, although the Red Sox will hope that they have enough arms in the bullpen to fashion something together.

Another worrying statistic is the difference between his ERA and xFIP. Basically, the greater the difference, the more likely it is that a pitcher was not performing as well as his stats suggested. Aceves' ERA of 2.61 is great, but his xFIP of 4.77 suggests that he will likely regress.

Aceves is not an ideal solution to the fifth starter problem. Then again, no one is. Miller was shellacked at times last year, and Doubront, Cook and Padilla have battled serious injuries in the last few years. Boston had better hope Beckett and Buchholz have good years because the back end of the rotation is worrying at best.