England flanker Sam Underhill is unlikely to play any part in the Six Nations after his club Bath revealed he requires an ankle operation.
Underhill sustained the injury when coming on as a replacement in Sunday's 35-34 defeat by Northampton and with no date given for his return, he looks set to miss the entire championship.
England face a tricky opener against back-to-back champions Ireland in Dublin on 1 February.
"Sam will undergo surgery to rectify a new ankle injury. There is no set timeframe on his recovery," a Bath medical update said.
England are well stocked for back rows but losing Underhill is still a major blow for head coach Steve Borthwick, who will name his Six Nations squad on Tuesday.
After being overlooked for the World Cup squad in 2023, the 28-year-old re-established himself last year by starting throughout the Six Nations and in all three Tests on the summer tour to Japan and New Zealand.
An ankle issue sustained on tour required surgery, delaying his start to the new campaign and forcing him to sit out the opening two matches of the autumn against the All Blacks and Australia.
But he was restored at openside for the clashes with South Africa and Japan that closed out the campaign, scoring a try in each game and impressing with his overall play.
A veteran of 40 caps, Underhill brings physicality to England’s pack, especially in defence where he is among the game’s most destructive tacklers.
It is the latest injury setback for Borthwick, who looks set to be without wing Immanuel Feyi-Waboso for the entire tournament because of a dislocated shoulder, while full-back George Furbank is struggling with a broken arm.
Flanker Ollie Chessum is closing in on his comeback from a knee injury, however, while scrum-half Alex Mitchell has fully recovered from a neck problem.
Meanwhile, the Rugby Football Union has agreed to hold a special general meeting after the Six Nations when chief executive Bill Sweeney will face calls for his removal.
A day after rejecting a letter from a grassroots revolt calling for a vote of no confidence in Sweeney on the grounds of bureaucratic technicalities, the RFU has performed a U-turn and the SGM will now take place in March or April.
Infuriated by the executives pay and bonus scandal that came to light in November, as well as other grievances, a formal letter featuring the signatories of 141 RFU member clubs and referees societies was submitted on Thursday.
Upon receiving the letter, however, the RFU claimed it contained "a number of inaccuracies" and that "it does not comply with the relevant requirements and is therefore invalid as a requisition for an SGM".
A spokesperson for the community game rebellion hit back by declaring that the RFU was "merely postponing the inevitable" – and less than 24 hours later the governing body has changed its position.
"The RFU is in the process of validating the additional information that has now been provided to request a SGM," a statement read.
"The notice to request an SGM contained a significant number of inaccuracies. However, the RFU respects the right of its members to call for an SGM and for their views to be heard."
The initial resolution under debate at the SGM – a date for which will be announced in the next two weeks – will feature a demand for the board to terminate Sweeney's employment "as soon as practicably possible".
The RFU insists Sweeney has the full support of the board.
Accompanying the statement was an open letter sent to clubs by Bill Beaumont, whose appointment as interim chairman was ratified by the council on Friday.
Beaumont has replaced Tom Ilube, who stepped down last month in response to the outcry over the scandal, and will embark on a nationwide tour of rugby clubs in January and February to debate the concerns of RFU members.
"It is very clear the game wants and needs unity and it is my priority to help to bring the game together," Beaumont said.
"This is a serious moment for the game of rugby in England. There have been demands for change without clarity on the real reasons why, or proposals for an alternative vision.
"There has been a call for a SGM and we will respect the right of members to have their views heard.
"Our sport has a long history of in-fighting and we sometimes lose sight of what is best for rugby as a whole. Whatever we do next, it needs to be for the good of the English game."
It was revealed in the RFU’s accounts published in November that Sweeney received pay of £1.1million pay for the 2023-24 financial year, which comprised an increased salary of £742,000 and a bonus of £358,000.
Bonuses totalling almost £1million were paid to a further five executives even though the RFU reported an operating loss of £37.9m for 2023-24, the highest it has ever recorded.
In addition, 42 staff were made redundant in September, the England men’s team won just five of their 12 matches in 2024 and grassroots participation is in decline.
Other areas of contention mentioned in the letter sent to the RFU are its excessive bureaucracy and poor governance, the cutting of development officers, the "debacle" over the introduction of the new tackle-height in the community game and the cost of sacking former England head coach Eddie Jones.
