Speaking after the weigh-in for Saturday night's WBO welterweight title fight between Manny Pacquiao and Johsua Clottey at Cowboys Stadium, Jones mentioned that he remains fond of Ellis, whom the team drafted with a first-round pick in 1998.
Ellis' agent, James Williams, said his client would be open to rejoining the Cowboys after spending one season with the Oakland Raiders, where he was tied for the team lead with seven sacks.
"That's not unrealistic," Jones said. "That's the best way to say that. It's not unrealistic thinking on his part or in my mind, I think that's best left unsaid."
There is no rush for the Cowboys to sign Ellis, who is an unrestricted free agent. Dallas has two starters at outside linebacker in DeMarcus Ware and Anthony Spencer plus younger players such as Brandon Williams, Victor Butler and Steve Octavien.
Williams said Ellis wouldn't mind coming off the bench and being a third-down pass rusher, something the Cowboys hoped he would do in 2008, his last season with the Cowboys.
Ellis, who was cut by the Cowboys last summer, is eighth on the team's all-time sack list with 77.