Although the Dolphins acquired Rosen from the Arizona Cardinals for a second-round pick during the NFL draft, he wasn't able to beat out Fitzpatrick for the starting job in training camp.
Rosen saw brief action in each of the first two weeks, going 8-for-21 for 102 yards and two interceptions in blowout losses. Fitzpatrick went 25-for-50 for 274 yards with one touchdown and four picks in his starts.
Rosen, the 10th overall pick in the 2018 draft, completed 55.2% of his passes for 2,278 yards with 11 touchdowns and 14 interceptions for Arizona as a rookie.
Miami has registered just 10 points through two losses to begin the season.