But there was better news for England head coach Eddie Jones yesterday with Billy Vunipola and Maro Itoje back in full training and available for Saracens this weekend, while Scotland full-back Stuart Hogg is due to return shortly.
North was hurt in Northampton’s 50-21 defeat to Harlequins on Saturday in his first game back for 11 weeks after ligament damage in the same joint.
Northampton say he will need up to four weeks’ rehab, which puts him out of Wales’ opener against Scotland on February 3 and struggling for the clash with England a week later.
The previous injury forced him out of the autumn internationals, and he has had a series of high-profile concussions in a career blighted by ill-fortune.
North, who has 69 caps, missed out on a Test spot on the Lions tour and left New Zealand early with hamstring trouble.
Wales coach Warren Gatland was forced to look at new wing options in the autumn and played a combination of Steff Evans, Hallam Amos, Liam Williams and Alex Cuthbert for the four matches.
North’s injury is also a blow for Northampton, who have lost 11 out of 12 games and recently sacked director of rugby Jim Mallinder.
North is leaving the club at the end of the season to head home to Wales although he has not signed for a region yet.
He has scored 35 tries for Saints in 81 games since joining from the Scarlets in the wake of his triumphant Lions tour to Australia in 2013.
Scotland could be reinforced by the return of Hogg, who injured his hip in the warm-up ahead of Scotland’s autumn Test against Australia.
Hogg, who was invalided out of the Lions tour with shoulder trouble, is expecting to return in two weeks’ time and should be fit for the tri to Cardiff.
“Hopefully I’ll be back on the pitch in the next couple of weeks and ready to rock and roll again,” Hogg told BBC Radio 5 live’s Rugby Union Weekly.
“In the warm-up, I kicked the ball and I felt as if somebody had stabbed me in my hip. It was a bit frustrating because I was just coming back from a long-term shoulder injury, I was feeling good, starting to get a little bit of form back and had to start back at square one.”
No8 Vunipola missed England’s autumn internationals with a knee injury and has not played since September 23, while Itoje broke his jaw at the start of December against Harlequins.
The Saracens pair were back in full training with their club yesterday and are expected to be available for the Premiership trip to Wasps on Sunday.
They spent two days with England in Brighton earlier in the week and the club is expecting them to hit the ground running.
Saracens director of rugby Mark McCall said: “They have taken part in training and we will make a decision on their involvement later in the week.
“Maro has been able to train and run from a week after it happened so he has been able to take part in lots of what we have been doing.”
Saracens have signed scrum-half Nic Stirzaker on a three-month deal to provide injury cover.
The Australian has been with the Rebels in Super Rugby since 2012 and McCall moved to sign him because Henry Taylor is out for the season and Richard Wigglesworth has been injured recently.