So I guess the Pirates carry 12 pitchers, including one closer and five starters, with two left-handed setup guys, two right-handed setup guys, and two swingmen and/or mop-up guys in the bullpen. They may not need a fifth starter until mid-April, so they could start the season with an extra mop-up guy or a three-man right-handed setup team.
On the left-handed side, I expect Grabow and Marte, and Burnett (or Fossum) as a swingman.
On the right-handed side, I count eight guys for, at most, four jobs: Carrasco, Dessens, Kim, Kuwata, Meek, Osoria, and Wright. I have no idea how this will turn out. Osoria and Meek have achieved good results this spring, and they are young; Carrasco has pitched better than I expected, but he is an old man at 37. Dessens got a late start, and he looks more like a swingman or spot starter than a setup person. With Burnett doing well, it does not seem urgent to have him on the roster in early April. Kim and Kuwata have not pitched so well, and they seem to be competing for "guy with funky style" job -- if there is one of those. Jaret Wright has pitched five spring innings without a strikeout, and like Fossum, he does not look like someone to press into a setup job. Kim may also be someone to steer toward a AAA starting job or a swingman role. The Pirates have no shortage of these swingman/mop-up/seventh starter guys.
Did I forget anybody?
It looks to me, after half an hour's thought, that some two of Meek, Osoria, and Carrasco will get right-handed setup jobs. It also looks possible that all three could make the roster for Opening Day.
And all three have been pitching every third day, so maybe we'll see Osoria and Meek as the second and third pitchers in the next game.