Wallach was optioned to Triple-A Louisville on Monday.
Wallach is no longer needed as catching depth with Stuart Turner back from the paternity list, so he'll head back to Louisville for the time being. He went 0-for-4 in the only game he appeared in for the Reds, which was also his big-league debut. The 25-year-old will now focus on improving his unimpressive .226/.280/.398 line in 64 games with Louisville this season.