Coach Jim Mora said Monday that what was thought to be a cracked rib sustained in the first quarter of Seattle's loss at Arizona on Sunday is a bruised lung -- "and potentially, possibly a cracked rib."
A source told ESPN NFL Insider Adam Schefter on Sunday that Jones had bleeding in his lung.
Doctors had Jones stay behind overnight in an Arizona hospital as a precaution. Jones flew back to Seattle on Monday.
"He's OK," Mora said, after speaking to Jones while Seattle's lead runner was at the airport in Phoenix. "They just took the proper precautions in not having him travel with that injury.
"At this point, I would say it would be unlikely that he would be cleared to play on Sunday."
Mora said Forsett and third-stringer Louis Rankin will be getting more carries over the next few weeks, if not the final seven games.
It may be that time of year for Seattle to try out young players, for the second season. The Seahawks are 3-6 and essentially four games out of the NFC West lead with seven games remaining since the Cardinals own the first tiebreaker.
Information from The Associated Press was used in this report.