Joshua Garnett is bound for the operating room.
The 49ers offensive lineman will get his knee cleaned out on Thursday, 49ers head coach Kyle Shanahan announced on Wednesday.
"Timeframe, I haven’t been given one yet," Shanahan told the media. "I know I’m hoping that he has a chance for Week 1, but I know that’s going to be a battle.”
The season opener is on Sept. 10 against the Panthers.
Garnett started 11 games at right guard last season.
The 49ers traded up into the first round to select the Stanford product with the 26th overall pick in 2016.
On Tuesday, Daniel Kilgore -- the 49ers' projected starting center -- took some snaps at guard.
“Just trying to go through all possibilities. Knowing Garnett is going to be out a little bit, just seeing what can be our best three out there for Week 1," Shanahan said on Wednesday. "You want to try all possibilities.
"We know Kilgore has done a good job at center. We wanted to see him a little bit more at guard. We’ve got to shuffle all that stuff because we’re still a ways away too. You know, you’ve got to be prepared for any other type of injuries. You’ve got to be prepared on game day. Depending on how many guys you dress, what are you going to do when you lose guys.
"I mean, you have to move guys around, so that’s something that we did yesterday and we’ll continue to do throughout camp.”
The 49ers released Jeremy Zuttah on Wednesday morning.