With the offseason now mostly over, here's a guess at how the 25-man roster might look when camp breaks in a couple months.
C Chris Snyder
1B Lyle Overbay
2B Neil Walker
SS Ronny Cedeno
3B Pedro Alvarez
OF Jose Tabata
OF Andrew McCutchen
OF Garrett Jones/Matt Diaz
This all looks pretty clear at this point, and I don't see the Pirates doing a whole lot between now and April to change the starting offense. I had hoped that they would find a new starting infielder somewhere, but that didn't happen, unless you count Overbay, which I don't.
C/OF Ryan Doumit
UT Josh Rodriguez
OF Garrett Jones/Matt Diaz
1B/OF Steve Pearce
OF John Bowker
I'm not sure this is how the bench will actually look, because it's light on guys who can field. Right now, however, the Pirates are clearly trying to trade Doumit but haven't managed to do so, so if he's still here he definitely has a spot. I could see the Pirates using Jason Jaramillo as their backup catcher, but since they were willing to use Doumit as a catcher last year after Chris Snyder was acquired, I imagine that's what they'll continue to do.
Rodriguez makes the team because he's a Rule 5 guy and because, well, he's probably just better than the rest of their utility infield options, like Pedro Ciriaco. I could see both Rodriguez and Ciriaco making the team, but I think that's probably less likely than just taking one of them.
The Pirates seem set with the Jones/Diaz outfield platoon, so one of those guys will be on the bench most days. That leaves two spots, and I see them taking Pearce and Bowker as a left/right corner tandem, although substituting someone like Garrett Atkins, Andy Marte or Josh Fields for Pearce is, I guess, a possibility. Bowker makes the team because he's out of options and there isn't anyone else who's obviously more useful. Pearce makes it because Jones and Overbay are lefties and Pearce is a righty. Pearce probably isn't high on the Bucs' list of priorities, though, and Atkins used to play for Clint Hurdle in Colorado.
UPDATE: Some of you in the comments are probably right that another infielder, probably Ciriaco or Corey Wimberly, will replace one of Pearce or Bowker on the roster. Wimberly might be the more likely of the two since he can also play center. Both he and Ciriaco are pretty dismal at the plate, though, so maybe I was just wishing the Pirates would decide to go with one utility guy and fill the rest of the bench with decent hitters. I think Pearce is a better bit than Bowker since he's a righty, but since he has an option left, he'll probably be the one who doesn't make it.
McDonald, Maholm and Ohlendorf are locks, and Correia, who's on a two-year contract, is probably pretty close. That leaves one more spot for Morton, Brad Lincoln or Scott Olsen, although if Rudy Owens pitches well in Spring Training, I wouldn't completely rule out the possibility that he gets it. My best guess is that Morton wins the job - the Pirates clearly like him a lot, and he's out of options. Lincoln has an option, and the structure of Olsen's contract is such that it appears the Pirates will mostly want to use him as a reliever, and probably won't start him except as a contingency plan.
Hanrahan, Meek, and Resop are locks, and I think Veras, despite his non-roster status, is pretty close. Olsen should stick because he's on a major-league deal and throws with his left hand, while Jeff Karstens sticks because he's on a major-league deal and is versatile (in that he's mediocre as a reliever and as a starter).
As for the seventh spot, your guess is as good as mine. I do think the Pirates will use seven relievers because, well, they pretty much always do. A lefty like Tony Watson is a possibility, but I think Ascanio is the most likely choice, because he's out of options and plainly has a bunch of upside. One of the few nice things about having someone like Karstens in the bullpen is that his rubber arm gives the Pirates the flexibility to carry Ascanio, who is recovering from injuries and is essentially a Rule 5 guy at this point. Kevin Hart is also out of options, but I think the Pirates would be more likely to be able to sneak him through waivers - he hasn't pitched since last April and wasn't particularly good for quite a while before that, whereas Ascanio at least had a successful rehab stint last year and held up well in winter ball in Venezuela.