The Athletics optioned Smith to Triple-A Las Vegas on Friday.
With Drew Rucinski (hamstring) returning from the injured list Friday, Smith will serve as the roster casualty for the A's. The 27-year-old reliever holds a 6.30 ERA and 1.60 WHIP through 10 innings this season, and he will likely need to make some adjustments in the minors before he can rejoin the MLB roster.