Joe Staley Suffers Knee Injury in Preseason Game vs. Vikings

San Francisco 49ers offensive lineman Joe Staley suffered a knee injury in the first half of Sunday's preseason game against the Minnesota Vikings.

Matt Maiocco of NBC Sports Bay Area reported the news and noted Staley would not return to the contest.

After the game, 49ers head coach Kyle Shanahan said he is optimistic Staley will be okay, noting he wanted to return to the game after the injury , per Tom Pelissero of USA Today.

According to Cam Inman of the Mercury News, John Theus played left tackle after Staley exited. Inman also pointed out it didn't seem like a particularly worrisome setback on the sideline:

While the 49ers haven't enjoyed a winning season since 2013, Staley is one of the steady presences on the roster. He played 13 games last year, which was the first time he failed to play all 16 since the 2010 campaign.

He is also a five-time Pro Bowler, and Sam Monson of Pro Football Focus noted he had the site's best grade last year among all 49ers offensive lineman with an 81.4. San Francisco can ill-afford to miss him for significant time this season if it hopes to surprise in the NFC West, which is why it is a relief for the team it didn't appear to be a serious setback.

If Staley were to miss time, Theus would likely fill in for him until he was ready to return.

Staley and the 49ers open the regular season on Sept. 10 against the Carolina Panthers.