Richardson was optioned to Triple-A Louisville on Monday.
Richardson was called up from Louisville to make his big-league debut Sunday, but he was dealt the loss after giving up four earned runs on four hits and three walks over three innings. The performance wasn't enough for him to stake a claim to a permanent spot in the Cincinnati rotation, but he could, however, return to the majors before the season comes to a close. Cincinnati called up right-hander Brett Kennedy from Louisville in a corresponding move.