Koch was designated for assignment by the Diamondbacks on Sunday.
Koch was quite poor in 20.2 innings of relief, posting a 9.15 ERA while walking just 9.4 percent of opposing batters. With a career 4.88 ERA in 125.1 innings and a considerably worse 5.99 FIP, it doesn't appear particularly likely that he'll be claimed off waivers. Jon Duplantier was called up to take his spot in the bullpen.