The Pirates announced that they have placed Jason Grilli on the 15-day disabled list (retroactive to April 21) with a left oblique strain. The club has recalled Jared Hughes and he will be on the active roster for tonight's game.
Grill has had a rocky start to the season, blowing three saves, including back-to-back save opportunities against the Brewers on April 19 and 20. Although his fastball velocity has been down about 0.8 MPH from last season, there was no real indication of a problem in his last outing, when his fastball averaged 93.3 MPH. This development is a little bit surprising, since there has not been any talk of an injury issue involving the Pirates' closer.
For the season, Grilli has appeared in eight games, gained four saves, and posted a 4.50 ERA with an .801 OPS against.
UPDATE by Charlie: Actually, the Pirates haven't placed Grilli on the DL yet. The reason is that Hughes was on the active roster during part of Grilli's retroactive period (that is, between April 21 and now). Therefore, Hughes isn't on the active roster right now, and the Pirates' bullpen is a man short.