He played only seven snaps in the loss to the Raiders, and Rivers took a beating with right tackle Sam Tevi also out.
Okung underwent an MRI on his injured groin Friday, and results revealed a strain, coach Anthony Lynn said, via Daniel Popper of TheAthletic.com.
Lynn characterized Okung as “questionable” for next week.
Tevi underwent surgery Friday to remove cartilage from his knee, Lynn said, but Tevi is not done for the season.
Rivers took five sacks and five other quarterback hits Thursday night. He also threw three interceptions and fumbled, though the Chargers recovered the fumble.