The 49ers placed running back Isaac Guerendo on the reserve/physically unable to perform list, Jeremy Fowler of ESPN reports.
Guerendo will miss the first four games of the season, but he can return to practice as early as Week 3.
He missed all of training camp after injuring a pectoral muscle in late May.
The 49ers have Christian McCaffrey, Kaelon Black and Jordan James as their top three backs.
Guerendo, 26, is entering his third season.
He totaled 84 carries for 420 yards and four touchdowns as a rookie in 2024 but did not play an offensive snap in 2025. In 14 games last season, Guerendo played 173 special teams snaps.
