Wales flanker Ross Moriarty has suffered a fresh back injury in training with Gloucester.
The 23-year-old has played once, on 4 November against Leicester, since injury forced him out of the British and Irish Lions tour to New Zealand in July.
Gloucester boss Johan Ackermann said no timescale has been put on his return.
"It's not the same injury, but it is similar symptoms that we just manage and treat," said Ackermann.
"They don't want to give us a timeline because it just adds pressure to the player, but obviously we've backed off a bit with him coming back into games.
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"He's doing his rehab, he's doing his running - all those things to get him back, and once they feel they've built him up enough then they will get him back on the field."
Moriarty's injury recovery after the Lions tour meant he was not included in the squad for Wales' autumn internationals which began with a 29-21 defeat by Australia on 11 November.
Seven days earlier he lasted 68 minutes of an Anglo-Welsh Cup comeback defeat for Gloucester at Leicester.
He was not considered for Gloucester's next game, a 47-7 win over London Irish in the Anglo-Welsh Cup.
Wales' back-row problems
Moriarty will miss Gloucester's Friday 17 November game against Saracens at Kingsholm in Aviva Premiership, while Wales host Georgia in Cardiff on Saturday 18.
Warren Gatland's side are without Lions flanker and captain Sam Warburton while Justin Tipuric missed the Wallabies encounter because of injury.
Wales' flankers against Australia were Josh Navidi and Aaron Shingler and they hope Tipuric will be fit to face The Lelos before Wales go on to host New Zealand and South Africa.
Ackermann added: "The injury wasn't sustained [in a game], it was actually in our training.
"He trained well, but he said he feels a bit sore and stiff again and obviously we took him off the field and the medical staff feel it's not worth pushing him while there's symptoms."