Arizona designated Vieira for assignment Saturday.
The Diamondbacks traded for reliever A.J. Puk on Thursday and now that Puk has reported to the team, Vieira will lose his spot on the 26-man and 40-man rosters. Saturday's move marks the third time Vieira has been designated for assignment this season, and he's fallen to a 5.21 ERA in 38 innings split between Milwaukee, Baltimore and Arizona.