All three just came available in my fantasy league. Who should I pick up?
Tim Wakefield, since he’s the only one out of the three that I’ve heard of. 
And Wake’s the only one who’s both healthy and sane.
Wake’s also likely to pitch a lot more innings, by virtue of being a knuckleballer, and he’s got a very good defense backing him up.
What are your scoring categories? I would lean towards Ben Sheets. Look at Tim Wakefield’s likely contribution this season–an ERA around 4.5, about 5 strikeouts per nine innings, 10-12 wins, WHIP of 1.3-1.4…there are a hundred guys on your waiver wire who can do that. Sheets is still making his way back from arm woes, but at least he has a chance to be something more.
I left the Baseball Prospectus at home, so I don’t have the PECOTA numbers for Sheets or Wakefield, but I know this: don’t pick Dontrelle.
I’m going with Sheets as well. His ceiling is far higher than Wake’s, by a mile. Dontrelle hasn’t been the same since he stepped out of the game. (He wasn’t quite Dontrelle before then, either - but I think he’s done.)
I’d also go with posting fantasy baseball questions in the “Other fantasy baseball” thread to avoid clutter, but that’s just me.
Dontrelle is in the Tiger rotation and pitched well in spring training ,which allowed the Tigers to dump Nate Robertson. The last couple years Willis was a total zero. But he will get his opportunity.
Standard categories: W, K, Saves, ERA, WHIP
Sheets.
Sheets is a no brainer. If Sheets gets 50% back to his previous form he is still far more valuable than Wakefield or Willis. Wakefield probably loses his starting spot once everyone is healthy and Willis still has proven he can throw strikes consistently.
As promised, PECOTAs for Sheets, Willis, and Wakefield:
Sheets: 9-7, 99 Ks, 0 saves, 3.80 ERA, 1.26 WHIP
Willis: 3-6, 42 Ks, 0 saves, 5.93 ERA, 1.69 WHIP
Wakefield: 6-8, 63 Ks, 0 saves, 4.99 ERA, 1.47 WHIP
Sheets is your man if, and it’s a big if, he’s fully recovered. But he is far enough ahead of Wakefield I think it’s worth the gamble.