Vespi was optioned to Triple-A Norfolk on Wednesday.
Vespi picked up a save in late June since a game was called after six complete innings, but he served mainly as a middle reliever during his time in the Orioles' bullpen. The southpaw made 11 relief appearances during his month with the major-league club and posted a 6.35 ERA and 1.32 WHIP in 11.1 innings. Right-hander Beau Sulser was called up to take his place in the bullpen.