Los Angeles Chargers rookie wide receiver Mike Williams, selected No. 7 overall this spring, might not play a single down in 2017.

He’s been out with a back injury (mild disc hernation) since OTAs, and now ESPN’s Adam Schefter is reporting Williams might need season-ending back surgery.

“Williams recently received a second epidural on his herniated disk in a last-ditch effort to have him ready at some time during training camp, though the Chargers are preparing as if he will not be ready by that time, per sources.”

“This may be a lot more serious than people thought,” said one source familiar with the injury.

This is the worst possible news for Williams, and for the Chargers, who hoped he’d supercharge their offense. A star at Clemson last year, Williams was a big part of the team that won the national championship over Alabama. He finished the season with 98 receptions for 1,361 yards and 11 touchdowns.

Williams missed most of the 2015 season with a fractured bone in his neck after he collided with a goal post.