Colorado had designated him for assignment. Jason Grilli wasn't terrible the past couple of years with the Rockies but was so far this year. Will be interesting to see how this plays out with the other pitching machinations.
Update: The accomanying moves are that Kris Benson has been outrighted to OKC, so that is a straight swap, both 25 and 40. Brandon McCarthy is officially DLed, and Guillermo Moscoso has been called up to replace him on the 25 man roster.