Both Rosen and Walter were in line to be exclusive rights free agents in the coming months.
Rosen, 23, is a former first-round pick of the Cardinals back in 2018. Arizona traded him to the Dolphins for a second-round pick after just a year during the 2019 NFL Draft.
Rosen was entering the third year of his four-year, $17,664,284 contract and stands to make base salaries of $660,000 and $750,000 over the next two years of the agreement. The contract included a fifth-year option for the Dolphins to pick up in 2021.
Miami waived Rosen coming out of camp and he went unclaimed on waivers. He later signed on to the Buccaneers’ practice squad. San Francisco signed him off Tampa Bay’s practice squad late in the season.
In 2019, Rosen appeared in six games for the Dolphins and completed 53.2 percent of his passes for 567 yards, one touchdown and five interceptions.