Carlos Villanueva has been something of a swingman his entire career, splitting his time between relief and starting as needed. While he's been a great reliever much of the time, his work as a starter has been a bit below-average. While the ability to have a pitcher who can handle two roles is huge, in fantasy baseball, it can be problematic if they aren't great at both. And Villanueva has not been great at both starting and relieving.
This isn't stopping him from attempting to start, though, as Villanueva reportedly wants to start at least 30 times per season with whoever he signs with. The Blue Jays, who need help in the rotation, are willing to promise him those starts, should that be what gets Villanueva back in their uniform. Should they want him to be a full-time starter, though, and in turn, should his starting matter to you?
Villanueva set a career-high with 16 starts in 2012, throwing 125 innings, another career-best. There were distinct differences in his performance as a starter against those out of the bullpen:
As a reliever, Villanueva had some issues with his control. His strikeouts were higher, though, and as expected with a reliever, his batting average on balls in play was lower. He also didn't give up nearly as many strong hits, as his Isolated Power allowed to opponents as a starter was .215. Historically, this is what he's looked like as a starter: his career line allowed is .273/.328/.476 in 56 starts and 315 innings, and normally, he doesn't even have the impressive K/BB he managed in 2012.
That's a below-average starter in real baseball, making him well below-average in mixed league formats. In AL- or NL-only, he might have a bit more value by virtue of having a job. But that doesn't mean he'd be a significant addition to your squad.
Villanueva would be cheap, as he's not a particularly popular fantasy player. He might get more play in the pre-season than he ever has before, given he would enter the season as a starter, but not enough to drive his price up during auctions, or cause him to be selected early on in drafts. If he falls to the end of your draft, he might be worth picking up just in case he can be an average hurler in his most-defined role of his career. But if the increased workload comes with increased fantasy attention, you're going to be better off focusing your energies elsewhere this spring.