The Diamondbacks designated Hoffmann (undisclosed) for assignment Monday.
He'll give up his spot on the 40-man roster to right-hander Justin Martinez (elbow), who was reinstated from the 60-day injured list in a corresponding move. After winning a spot in Arizona's Opening Day bullpen coming out of spring training, Hoffmann was demoted to Triple-A Reno after submitting a 7.71 ERA and 2.06 WHIP in 11.2 innings out of the bullpen. He hasn't made an appearance for Reno since June 5 due to an unspecified injury and moved to the Triple-A club's 60-day IL over the All-Star break.