The Diamondbacks outrighted Weems to Triple-A Reno on Thursday.
Weems will stay in the organization after none of MLB's other 29 teams put in a claim for the right-handed reliever when he was exposed to waivers earlier in the week. The 28-year-old has appeared in seven games between Oakland and Arizona this season, giving up 10 earned runs on six hits and six walks across 5.2 innings.