Justin Nicolino will start Wednesday night against the Dodgers, the Marlins announced Tuesday night.
Miami optioned Jarred Cosart to Triple-A New Orleans Tuesday afternoon.
Nicolino joined Adam Conely as options to join the Marlins' rotation with a solid spring performance. However, Conley ultimately won the competition while Nicolino opened the season in Triple-A.
Cosart struggled over his first three starts with the Marlins, but Nicolino's success in the minors also likely factored into Miami's decision.
Over 25.0 innings, Nicolino pitched to a 3.60 ERA and 4.35 FIP. He made four starts in New Orleans.
Nicolino received starting time with the Marlins last season, pitching to a 4.01 ERA and 4.85 FIP over 74.0 innings.
The Marlins now have three lefties in the rotation, with Nicolino joining Conley and Wei-Yin Chen.
It's unclear how long Cosart will remain in Triple-A, but if Nicolino thrives, he might give the club necessary depth moving forward.