The Browns' second-round draft pick out of Georgia, Jones tore his ACL when he jumped to intercept a ball during practice on Tuesday. When he planted his leg, receiver Dennis Northcutt dove into his knee.
"It was an unfortunate and a freaky type of a deal," Browns coach Butch Davis said Thursday.
The Browns didn't report the injury until Thursday.
The 6-foot-1, 215-pound Jones is a hard-hitting safety who was expected to play immediately for the Browns. He will have surgery June 22.
"It's pretty disappointing, but I just have to keep my spirits up," Jones said.
He said he's never had an injury this severe but he is focused on rehabbing the knee and getting ready for next season.
Little said Jones would have been a valuable backup, but they still have second-year defensive back Chris Crocker.
The Browns also have signed defensive back David Gibson, who was with Tampa Bay last season.
"It's unfortunate because the guy's just getting his feet wet. The season hasn't even begun," Crocker said of Jones. "You hate to see something end before it gets started."
The Associated Press News Service
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