Gareth Anscombe is out injured until at least late November, which will force him to miss Wales' autumn Tests.
The Cardiff Blues fly-half has been sidelined by a groin problem since Wales' tour matches against Tonga and Samoa last June.
The 26-year-old had been hoping to return in mid-October, but his recovery has been delayed for another six weeks.
With Wales starting against Australia on 11 November, that effectively rules Anscombe out of Wales' autumn series.
After facing the Wallabies at the Principality Stadium, Wales then play Georgia, New Zealand and South Africa on successive Saturdays in Cardiff.
Even if Anscombe has recovered by the end of November, his lack of match fitness is almost certain to count against him for the final Test against the Springboks on 2 December.
Anscombe has had problems with his groin in the past, having surgery in December 2016.
He has been receiving specialist treatment to cure the condition - known as Osteitis pubis - from Dr Mark Gillette, head of sports medicine at West Bromwich Albion Football Club.
"After the summer tour it flared up and if you are in that position and you have a groin injury, you need to get real rest and treatment as a kicker," said Blues head coach Danny Wilson.
"Gareth has ended up as our first choice 10 and been playing really well so we look forward to getting him back.
"It's frustrating for all of us when you don't have your best players for us but it's also important you don't try and put a band aid over it.
"Gareth has probably gone through that a little bit of that and it's important when he does come back, it's a position where this is gone and he is not being managed."
Cardiff Blues captain and Wales record cap holder Gethin Jenkins' return has also been delayed as he recovers from a calf injury.
The prop had been expected to return at the end of September but is still not fit to come back.
"He was probably a little but longer than we hoped but is on the road to recovery," said Wilson.
"He has been out for quite a long time now but is a model professional in his work ethic in trying to getting back."
Cardiff Blues have been hit by injuries to their leading players, with British and Irish Lions captain Sam Warburton (neck) and Wales flanker Ellis Jenkins (torn hamstring tendon) ruled out until the New Year.
New centre signing Jack Roberts will also be missing for at least a month with a knee injury after coming off in his competitive debut in the 39-16 defeat away against Munster.