The team said Wednesday the injury could sideline him for the rest of the 2008 season.
He was hurt last Sunday in Dallas's 20-13 loss to Pittsburgh, his first game since being reinstated by NFL Commissioner Roger Goodell for violating the NFL's player conduct policy.
During a turbulent first season in Dallas, the former West Virginia All-American was suspended six games for an alcohol-related altercation with a personal security guard at a Dallas hotel, a violation of his reinstatement arrangement.
"Adam Jones has a herniated disc -- maybe two -- in his neck and they are going to look at it again (Thursday)," Coach Wade Phillips said. "Our people don't think it's career-threatening or anything else, but he's going to see a doctor and be further evaluated."
In seven games, Jones has 26 tackles without an interception.