The Ospreys prop damaged elbow ligaments during the first half of the Ospreys shattering 24-12 defeat to London Irish which ended their European hopes.
Jones suffered the injury when a scrum collapsed but played on until half-time when he was replaced by Craig Mitchell.
"Adam has strained left elbow ligaments but it is too early to say how serious it is," said Ospreys coach Sean Holley.
"He felt he could not continue because it was affecting his lifting at the lineout and his scrummaging. There will be further investigations."
Jones will undergo tests today to reveal the extent of the injury which could put his RBS 6Nations involvement in doubt.
The news capped a nightmare week for Wales head coach Warren Gatland. First, on Wednesday, Jones' Lions team-mate Gethin Jenkins underwent surgery on a toe problem which rules him out of the entire Championship.
Days later it was revealed that Ospreys centre Andrew Bishop was out for eight weeks with an ankle injury. Then on Saturday, Wales hopeful Gavin Henson, a Lions tourist in 2005, limped out of Saracens 43-20 loss to Leinster with a calf injury.
"Gavin's got a calf injury," said Saracens director of rugby Mark McCall following the defeat. "We don't know the extent of it yet and he will go for a scan."
Wales kick-off their Six Nations campaign against England on February 4, but Martin Johnson's men are not without injury problems of their own.
Having already lost 2009 Lions tourist Tom Croft and Northampton Saints' Courtney Lawes, Johnson was dealt a major blow when his captain Lewis Moody hobbled off at The Rec pitch with a twisted knee.
Again the extent of the damage is yet to be determined but Bath coach Steve Meehan was quick to talk down the injury.
"Lewis twisted his knee in a driven lineout," said Meehan. "He doesn't seem too concerned - it's maybe a week off. He's quite confident there's nothing sinister there.
"I haven't spoken to our medical team but with these things it's 24 or 48 hours later."