England and Sale Sharks' Tom Curry has been ruled out of the Six Nations and is likely to miss the rest of the season after having hip surgery.
Curry, 25, has been troubled with the injury since playing a full part for England at the Rugby World Cup.
Sale director of rugby Alex Sanderson said surgery was the best option for the flanker "in the short term".
Meanwhile, England and Saracens back row Ben Earl will be available for the start of the Six Nations in February.
Earl, 25, injured his right knee during the warm-up for Saturday's Premiership victory over Harlequins.
Curry, who earned his 50th cap in the third-place play-off win against Argentina in October, will undergo an operation in two weeks' time.
"I know it sounds long term - the season - but it's not," added Sanderson.
"He's still a young lad and it's the best thing for him in the short term to ensure he's able to be more robust moving forward and to train and progress his game the way he wants to.
"The level of stiffness hadn't flagged up to this degree until this point in his career. The red flags were out that maybe there was something deeper here and apparently there is.
"I'm sure there will be ebbs and flows over the next four or five months and I hope to be part of that journey with him as we get him back to where he needs to be."
Curry also missed the Six Nations earlier this year because of a hamstring problem and the build-up to the World Cup through ankle ligament damage.
'Not playing might be good for Earl in the long run'
Earl and Saracens received a positive update on his knee problem on Tuesday.
A scan revealed medial meniscus damage, which has now been repaired, and he is likely to return in January.
"We anticipate he'll be out for between six to eight weeks," Saracens director of rugby Mark McCall said.
Earl was a standout performer for England on their run to the bronze medal in France, playing 80 minutes in six out of their seven matches.
"Ben had a minor knee procedure this morning," McCall added. "He's had a busy time with a lot of minutes in August, September and October, so to have a six-week period not playing rugby might actually be good for him in the long run."
England wing Elliot Daly suffered a minor hamstring injury in the warm-up and is expected to be available to face Northampton on 2 December.
However, Saracens centre Alex Lozowski damaged his anterior cruciate ligament (ACL) and faces a lengthy time on the sidelines.
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