The Astros are “hell-bent” on acquiring a closer, sources tell ESPN’s Jayson Stark. The Astros have made calls on Aroldis Chapman of the Reds, Andrew Miller of the Yankees, and Brad Boxberger of the Rays, as well as potential free agent possibilities. They’ve also spoken with the Phillies about Ken Giles, as had previously been reported.

Adding a closer would move current closer Luke Gregerson back to the setup role in which he excelled with the Padres and Athletics. A dominant ninth-inning type like Chapman or Miller would also give the Astros not only a terrific ninth-inning option but also enviable depth, with a bullpen that would also feature Gregerson, Pat Neshek, Josh Fields and Will Harris. Also, the bullpen’s 5.63 ERA in September and October and its eighth-inning implosion in Game 4 of the ALDS against the Royals are surely fresh in the organization’s mind, particularly after watching a Royals team with a hard-throwing bullpen win the World Series after beating them. It’s easy, then, to see the appeal of adding a shutdown closer.

Still, overall, the Astros’ bullpen was a key element of the team’s success last season, and Gregerson is a perfectly good ninth-inning man in his own right (although Stark notes that Gregerson’s K/9 was relatively low for a closer, at 8.6). Stark notes that the Astros might not want to pay the prospect cost of acquiring Chapman, Miller or Giles, and therefore could ultimately pursue hard-throwing setup-type relievers instead. Given the potential departures of lefties Tony Sipp and Oliver Perez via free agency, a lefty appears likely to be a priority, whether they add a closer or not.