The Ospreys due suffered the injuries in the 15-15 Heineken Cup draw with Leicester Tigers.
Triple Grand Slam star Jones was taken off early in the first-half after badly dislocating his thumb, while Hibbard suffered a recurrence of the shoulder problem that hampered his autumn campaign.
"Ryan has gone off to hospital," said Ospreys coach Steve Tandy.
"I think he has got a dislocation of his thumb. It may have popped through the skin as well.
"We have been patching Hibbs up since he hurt the same shoulder playing for Wales against Samoa in November if I'm honest.
"The way he goes about his business and turns up every week is just a ridiculous effort from the boy.
"We just had to take the kid off because he would have done himself harm otherwise."
Jones underwent surgery last night and is likely to miss at least some of the Championship.
There was no better news on the fitness of fellow Osprey Ian Evans. The giant second-row, who has a 100 per cent record in the Six Nations, had been ahead of schedule in his recovery from a knee injury.
But Evans is set to miss out on the Ospreys' final Heineken Cup clash with Treviso and is unlikely to return to action ahead of the Championship opener with Ireland on February 2.
"Ian probably won't come back next week against Treviso," admitted Tandy.
"I know Wales are decimated, but we will just have to review his situation as we go along."
That leaves Howley short of second-row options with Luke Charteris, Bradley Davies, Alun Wyn Jones and potentially Jones out of the clash with Ireland.
Cardiff Blues lock Lou Reed is now the only second-row that featured in the autumn that is still standing.
Howley names his Six Nations squad tomorrow.