The Pirates have designated Vin Mazzaro for assignment. This is no huge surprise -- Mazzaro pitched well last season and deserves to be on a big-league roster somewhere, but with him, Jeanmar Gomez, Bryan Morris and Stolmy Pimentel all out of options, something had to give. The Pirates probably preferred Gomez's ability to start and Morris and Pimentel's upside, and so Mazzaro, being a competent middle reliever but little else, was the odd man out. He'll likely be traded or claimed, and the Pirates won't get much in either case.
The Pirates also outrighted Andy Oliver, who had also been out of options but had no shot at making the team due to his control problems, to Indianapolis. So he'll stay in the organization. Mazzaro's roster spot will be occupied by Travis Ishikawa. Jeff Locke and Chris Stewart will open the season on the disabled list.
Barring another move, that should set the Pirates' roster, which now looks like this: