Rosen signed with the Buccaneers’ practice squad after being released by the Dolphins in September. The 49ers reportedly lost QBs Nick Mullens (elbow) and Jimmy Garoppolo (ankle) for the season. Rosen will back up starting QB C.J. Beathard in Week 16’s contest against the Cardinals. The No.10 pick in the 2018 NFL Draft owns a career 12:19 TD:INT ratio over 20 games with the Dolphins/Cardinals.