The Diamondbacks have designated Wily Mo Pena for assignment, reports Jack Magruder of FOX Sports Arizona (Twitter link). In corresponding moves, the D'Backs also optioned Juan Miranda to Triple-A and called up Brandon Allen and Geoff Blum.
Arizona signed the slugger to a $675K minor league deal in December and called him up last month to serve as a DH during interleague play. Pena hit .196/.196/.522 in 46 plate appearances with the Snakes and hit five homers, two of which were game-winners. Before this year, Pena's last appearance in the Major Leagues came in 2008 with the Nationals.