Oviedo was optioned to Triple-A Memphis on Friday, Derrick Goold of the St. Louis Post-Dispatch reports.
The young right-hander made his final start before the All-Star break in Wednesday's loss to the Giants, so he'll head to Triple-A so he can continue receiving work in the minors. Oviedo is a strong bet to rejoin the rotation when the Cardinals require additional starters during the July 19-22 series versus the Cubs.