The Diamondbacks optioned Del Castillo to Triple-A Reno on Saturday.
Del Castillo was summoned from Reno last weekend but will head back in favor of Pavin Smith, whose contract was selected in a corresponding move. Del Castillo has slashed .196/.249/.313 with five home runs, 24 RBI, 18 runs scored, one stolen base and a 13:55 BB:K across 195 trips to the plate at the big-league level this season.