RENTON – Defensive lineman Jesse Williams might need surgery after suffering a “serious” knee injury, according to coach Pete Carroll.

Williams left Wednesday’s practice on a cart after suffering the injury. Carroll said he didn’t know all of the specifics of Williams’ injury, but he called it a “serious situation.” When asked if it’s a possible season-ending injury, Carroll said, “It’s potential surgery. I don’t know the details of it yet.”

It’s another setback for Williams, the Seahawks’ fifth-round pick in 2013. Williams had one of his knees surgically repaired before his rookie season last year, and he missed all of the season because of a knee injury.

Williams was in the mix for a backup spot along the defensive line, and he had played some at defensive tackle and at defensive end in a similar role as Red Bryant a year ago.

Receivers Norwood, Richardson out

Rookie receiver Kevin Norwood didn’t practice because his sore foot isn’t getting any better, Carroll said. Norwood, a fifth-round draft pick, returned to practice on Wednesday after sitting out for a couple of days. But Carroll said Norwood’s foot hadn’t healed, and the Seahawks weren’t sure what the next step would be.

“His foot has not responded the way we had hoped,” Carroll said. “It’s OK today, but he’s not better. We’re just going to try to quiet him down and see what to do next. He’s had MRIs and all that stuff, and there’s nothing we can do at this point. But we’re trying to find the right solution: the footwear, the orthotics and all the different things we can do to try to help his foot.”

Paul Richardson, another rookie receiver, also didn’t practice because of a banged up shoulder. Richardson, a second-round pick, should return to practice on Saturday, Carroll said.

Jayson Jenks: 206-464-8277 or jjenks@seattletimes.com