Doctor and ex-Wales captain Gwyn Jones is not sure if Stephen Jones will be fit for the start of the World Cup.
Stephen Jones will miss all of Wales' World Cup warm-up games
The Scarlets fly-half has been ruled out of all three of Wales' warm-up games in August with a groin injury.
But team doctors say Jones should be back for Wales' opener against Canada in Nantes on 9 September.
"It is probable that Stephen will make that recovery, but groin injuries are notoriously difficult to predict when they will heal," Jones told BBC Sport.
"It's not like breaking a bone and they know you'll be back playing in eight weeks - this is soft tissue in an area that is complex at the best of times."
Fly-half Jones has a partial tear in his left groin, ruling him out of Wales' three warm-up matches in August.
There's a huge bond of loyalty between Stephen Jones and Wales coach Gareth Jenkins
Ex-Wales captain Gwyn Jones
But the 29-year-old is expected to be back in full training at the end of the month.
Regular Scrum V pundit Jones, who was forced out of the game with a serious spinal injury, is well placed to comment on his namesake's problems, having won 13 caps in the back-row for Wales but is now a doctor.
The former Cardiff flanker admits it is a risk for Wales coach Gareth Jenkins to keep faith with his preferred captain and fly-half.
But Jones says there is a huge difference between this decision and the one Jenkins took earlier in the week to drop Gavin Henson from the squad.
Henson is suffering with an Achilles problem, the latest in a long line of injuries the Osprey utility back has suffered.
"Stephen is at a point where he is supremely fit having worked very hard in the summer and he's now got a set-back of a few weeks in training," Jones added.
"That's in contrast to Gavin Henson, who has struggled to train for months and is now miles behind the rest of the squad.
"There's a huge bond of loyalty between himself and Gareth Jenkins, and also Stephen Jones is regarded by the other players as hugely influential.
"He's very good at analysing other teams and forming their own tactics.
"But having said that, I cannot believe that Gareth Jenkins would jeopardise the hopes of Wales in the World Cup on anything other than what he has been presented by the medical staff."