Weiss was sent down to Triple-A Louisville on Saturday, C. Trent Rosecrans of The Athletic reports.
In a corresponding move, the Reds activated Brandon Finnegan (biceps) from the 10-day disabled list. Weiss was previously brought up to the majors earlier this week but only appeared in one game, giving up four earned runs off two home runs and a pair of walks while failing to record an out against St. Louis on Thursday.