London - Wales' injury-prone wing George North looks almost certain to miss their opening Six Nations clash with Scotland on February 3 after injuring his knee last weekend.
The 25-year-old - scorer of 30 tries in his 69 Tests - suffered the injury in his club Northampton's 50-21 hammering by Harlequins last Saturday.
He missed Wales's four Tests last autumn with a previous knee injury.
"George North sustained an injury to his knee during Saints' defeat to Harlequins on Saturday at Twickenham which will require up to four weeks' rehabilitation," Northampton said in a statement."
North's injury adds to Wales head coach Warren Gatland's selection headaches as his injury list grows almost daily.
Two-time British & Irish Lions captain flanker Sam Warburton and fellow Lion, centre Jonathan Davies are out for the entirety of the tournament.
Number eight Taulupe Faletau is another injury absentee who is unlikely to be fit before March, and both flanker Dan Lydiate and wing Hallam Amos suffered injuries last weekend.