Liberatore was optioned to Triple-A Memphis on Friday.
Liberatore made his third major-league start Thursday against the Cubs and allowed four runs in 3.1 innings to take the loss. The southpaw has had an inconsistent start to his big-league career with a 5.54 ERA and 1.77 WHIP in 13 innings over three outings. However, the 22-year-old remains one of the Cardinals' top prospects, so it wouldn't be surprising to see him rejoin the major-league club at some point. Liberatore's demotion could signal that Steven Matz (shoulder) will be ready to rejoin the rotation next week.