Joshua Garnett will undergo arthroscopic knee surgery Thursday, coach Kyle Shanahan said Wednesday.
“Timeframe, I haven’t been given one yet,” Shanahan said in a video released by the team. “I’m hoping that he has a chance for Week 1, but I know that’s going to be a battle.”
Garnett started 11 games last season as a rookie after the 49ers made him a first-round choice. He was working as the team’s starting left guard until his injury.
Versatile veteran Zane Beadles, who started all 16 games for the 49ers last season, has stepped in at the spot in Garnett’s absence.
The 49ers released center Jeremy Zuttah on Wednesday after he failed to win the starting job. Starting center Daniel Kilgore has taken some snaps at guard, and Tim Barnes has taken snaps at both guard and center.