In that case, the Chargers' primary options at free safety would include Jaylen Watkins, who is coming back after missing 2018 because of a knee injury, and second-round pick Nasir Adderley, who has been out for most of training camp because of a hamstring problem.
"It's next man up ..." Lynn said. "We'll figure it out in the next three weeks."
The Chargers have three preseason games remaining, starting Sunday when they host the Saints in Carson.
Many of the starters are expected to play only a little, if at all. Quarterback Philip Rivers will not play. Instead, Tyrod Taylor, Cardale Jones and Easton Stick will be the Chargers' quarterbacks.
A young offensive line -- principally tackles Trent Scott and Sam Tevi and guards Forrest Lamp and Dan Feeney -- will continue to receive snaps.
"They've grown," Lynn said. "You can see it just in the games in the communication with the other linemen, which is important to get them in there .... They're going to play more than most starters, I can tell you that, but they won't play as much as last week (against Arizona)."
James' injury continued what has been a trying camp for the Chargers. Pro Bowl wide receiver Keenan Allen has been slowed by knee and ankle injuries and might not play in the preseason.
Left tackle Russell Okung is sidelined indefinitely since developing a pulmonary embolism in June.
Pro Bowl running back Melvin Gordon is holding out because of a contract dispute. Negotiations on an extension have featured little movement on either side.
James, a first-round pick out of Florida State, emerged as one the NFL's bright young defensive stars in 2018.