Wallach was optioned to Triple-A Jacksonville on Monday, Jordan McPherson of the Miami Herald reports.
Wallach had lost out on playing time recently, and he'll head to the minors after Jorge Alfaro (hamstring) was reinstated from the 10-day injured list in a corresponding move. Wallach slashed .203/.246/.271 with three extra-base hits, six RBI and two runs to begin the season.