Smith was optioned to Triple-A Reno on Friday, Theo Mackie of The Arizona Republic reports.
Smith will head to Triple-A in the midst of a cold spell at the plate, having batted .130 (9-for-69) with two homers, eight RBI, eight runs scored and 16 strikeouts over 69 at-bats in June. He'll head to Reno and look to get right while Kyle Lewis was called up to replace Smith on the major-league roster.