The Cardinals optioned Liberatore to Triple-A Memphis on Wednesday, John Denton of MLB.com reports.
Liberatore's demotion likely foreshadows Steven Matz's (shoulder) return to the rotation in the Cardinals' final game before the All-Star break Sunday against the Reds. St. Louis may have chosen to delay Matz's activation until the second half if Liberatore fared well in his most recent outing, but the Cardinals' decision to deploy the rookie behind an opener (Jordan Hicks) in Tuesday's 7-6 win over the Dodgers didn't pay dividends. Liberatore took a no-decision after giving up three earned runs in 2.1 innings, inflating his ERA to 5.33 through his first seven outings in the big leagues.