SANTA CLARA, Calif. -- San Francisco 49ers coach Kyle Shanahan revealed Saturday afternoon that second-year guard Joshua Garnett has suffered a knee injury that will keep him out for an extended period.
"I don't know exactly for sure, but I know there's some stuff in his knee we're probably going to have to clean up," Shanahan said. "I don't think it's anything long term, but it's going to be a little bit of time."
ESPN NFL Insider Adam Schefter reported Saturday night that Garnett's injury will keep him out at least a month, and it will likely take four to six weeks for Garnett to return.
Losing Garnett now might not be the worst thing for the Niners, as he could still be back in time for the start of the regular season (depending on whether he's sidelined for the full six weeks or merely a month). Nevertheless, it's a setback for Garnett, who has spent most of training camp working as the team's starting left guard.
Garnett had his share of ups and downs during training camp as he adjusted to a new scheme, but he seemed to be in line for a starting job in September. That was a bit of a departure from a consistent rotation in the spring that included Garnett and veterans Brandon Fusco and Zane Beadles.
Therein lies the good news. Although the Niners ignored the offensive line in the draft, they did invest in a number of linemen with experience in free agency. They traded for center Jeremy Zuttah, signed Fusco and center Tim Barnes late in the spring and inked restricted free agent tackle Garry Gilliam to a contract the Seattle Seahawks chose not to match.
Beadles stepped in for Garnett in Saturday's practice and figures to continue working in that role for the time being. He started there for much of last season, although he also played just about everywhere else on the line.
Having Fusco and Beadles on call to replace Garnett at guard means the Niners don't have to attempt to get an unproven youngster up to speed.
"They've both played [a lot of] football," Shanahan said. "They're definitely both guys the game's not too big for. You want to see how they do, and they're both doing a new scheme and being asked to use some new techniques that they haven't done before. It's always neat with veterans who have had success in this league, when they're willing to do that. They're OK with being uncomfortable. They've been a little bit, we've gotten them out of their shell a little bit. When you do that it starts off bad, but they're pretty mentally strong, confident people. They've both grinded with what we've asked them to do and now you can see it coming around and them getting better each day."
Should another injury strike, the 49ers also have Barnes and the loser of the center battle between Zuttah and Daniel Kilgore as options at guard. Even before Garnett's injury, the 49ers spent practice time training a handful of players at both the center and guard spots.