The Diamondbacks recalled Morillo from Triple-A Reno on Monday.
Morillo has made 31 appearances out of the Diamondbacks bullpen this season, posting a 4.94 ERA and 28:16 K:BB over 27.1 innings. The 26-year-old could work his way into high-leverage appearances as part of an unsettled bullpen, although he's unlikely to be in the mix for save chances right away.