The Reds optioned right-hander Michael Lorenzen to Triple-A Louisville on Thursday. The young hurler got roughed up in his outing against the Padres on Tuesday, allowing seven runs in just 1 1/3 innings.
Though the team hasn't specified how long Lorenzen will be down for, he could realistically be called back up when the rosters expand on September 1.
His demotion clears a spot for fellow rookie John Lamb, who will start and make his Major League debut on Friday.