Per The Athletic's Matt Barrows, 49ers head coach Kyle Shanahan said the injury should take fewer than eight weeks to heal and they don't anticipate putting Staley on season-ending injured reserve.
The injury occurred when San Francisco running back Raheem Mostert accidentally clipped Staley's left leg as the offensive lineman was blocking a Bengals defender. The six-time Pro Bowler briefly attempted to walk on the sidelines before being taken to the locker room on a cart.
Staley has anchored San Francisco's offensive line since being a first-round draft pick in 2007. The 35-year-old started all 16 games last season for the first time since 2015.
Until the 49ers get their star left tackle back, they could use Justin Skule to protect Jimmy Garoppolo's blind side. Skule is a rookie who was a sixth-round draft pick out of Vanderbilt.