Smeltzer was designated for assignment by the Marlins on Friday, Jordan McPherson of the Miami Herald reports.
Johan Quezada will join the club in a corresponding move. Smeltzer, 27, had struggled to a 6.75 ERA, 1.83 WHIP and 8:4 K:BB through 12 innings this season with Miami after performing pretty well in a swingman role last year with the Twins. He could draw interest on waivers.