Allen was designated for assignment by the Diamondbacks on Sunday, Jeff Sanders of The San Diego Union-Tribune reports.
The 27-year-old surrendered six runs in one inning during Saturday's game against the Padres, and he's now been removed from the 26-man and 40-man rosters. Allen had a 3.67 ERA, 1.30 WHIP and 20:9 K:BB over 27 innings this season prior to Saturday's implosion, so he could generate some interest on the waiver wire.