Per the team's site, the Pirates have activated closer Jason Grilli from the disabled list and recalled catcher Tony Sanchez, outfielder Andrew Lambo, and pitchers Jeff Locke and Jared Hughes.
Grilli's activation is arguably a mild surprise. He struck out the side in his last one-inning rehab stint, but by his own estimation, he was throwing at 85%. His velocity was in the low 90s, which is well below his norm. Logically, the Pirates might want to try him in a couple lower leverage situations before moving him back to the closer role. The closer designation, though, carries roughly the same weight as being made Pope, so we'll see.
(UPDATE by Charlie: The Pirates will "transition" Grilli back into closing, which means he won't close right away.)
I wouldn't hesitate to bet that Locke will return to the rotation. Kris Johnson probably isn't hugely popular right now, but he's eaten up LH hitters in the minors the last two years, so he could be useful as a LOOGY. Oh, wait . . . .
Anyway, these moves bring the Pirates closer to every manager's ultimate goal of a 25-man bullpen and provide Clint Hurdle with plenty of pinch hitters to boot. And Twitter will be the better for it, too.