The Marlins optioned Munoz to Triple-A Jacksonville on Tuesday.
Munoz will head back to the minors after giving up six earned runs in 4.2 innings during Monday's loss to the Dodgers. George Soriano was recalled from Jacksonville to fill Munoz's roster spot, though Jesus Luzardo (elbow) and Braxton Garrett (shoulder) could return from their rehab assignments within the next several days to help fill the open spot in Miami's rotation.