The Pirates have designated Jose Tabata, and Chris Volstad also appears to be on his way out, Rob Biertempfel tweets. Gorkys Hernandez and Steve Lombardozzi will join the Pirates.
As we've seen in the past, the Pirates couldn't really get rid of Tabata even if they wanted to. When he's designated for assignment, that doesn't mean the same thing as it would with most players. Since no one will want to pick up his contract, and since he won't want to give up the guaranteed money on that contract, he'll likely end up back at Indianapolis. We'll see what happens with Volstad.
Replacing Tabata with Hernandez mostly seems like replacing one underwhelming player with the next one on the list, but Hernandez has hit well at Indianapolis (.275/.359/.415 with five home runs, after he hit none last season) and is a plus defensive center fielder. He has the potential to be a useful bench player, since his defense can help in the late innings. Lombardozzi was hitting .316/.375/.368 at Indy. As before, he isn't likely to hit a whole lot at the big-league level, but he's versatile.
UPDATE: Volstad has also been designated for assignment. He's unlikely to be claimed, but he should have the right to refuse an outright assignment, so it's possible he'll leave for another organization. That's not a big deal, fortunately.