England’s injury crisis in the back row has worsened with Harlequins flanker Chris Robshaw ruled out of the autumn internationals with a knee problem.
Robshaw is understood to have had surgery on the issue, and becomes the latest key player to be sidelined.
Number eight Billy Vunipola and lock Joe Launchbury are already missing because of injury, while Nathan Hughes is facing suspension.
England play South Africa, New Zealand, Japan and Australia next month.
Harlequins boss Paul Gustard said: “We are hugely disappointed to lose Chris for a short period of time while he recovers from this injury.
“Not least because he has been one of our standout performers across our first seven games this season and also because this period in the calendar provides the opportunity to represent England in the Autumn Internationals and I am sure he would have featured strongly in Eddie Jones’ plans for those matches.”
Former captain Robshaw, who has 66 caps, has been a regular for England under head coach Eddie Jones, starting seven of the eight Test matches in 2018.
He was dropped for the second Test against South Africa in Bloemfontein, before impressively returning to the side in the victory in Cape Town a week later.
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England’s back row options
Robshaw will be out for up to eight weeks, and his absence is a major blow to Jones given the injuries in the forward pack.
England have options on the blind-side flank, but they lack Robshaw’s experience, with Saracens’ Michael Rhodes, Brad Shields of Wasps and Newcastle’s Mark Wilson among those pushing for inclusion.
Locks Courtney Lawes and Maro Itoje can also operate in the back row.
Meanwhile, at number eight, the uncapped Bath 21-year-old Zach Mercer appears to be next in line, although the experienced Ben Morgan impressed in Gloucester’s Champions Cup win over Castres on Sunday.
Morgan, 29, who has won 31 caps, has not played for his country since the 2015 Rugby World Cup, but told the BBC he remains hopeful of a recall to the international fold.
As well as at the back of the scrum, England are stretched at loose-head prop, with Joe Marler having retired from international rugby, Mako Vunipola a doubt with a calf strain, and Ellis Genge also injured.
‘Eddie Jones will be having nightmares’
Former England wing Ugo Monye told the Rugby Union Weekly podcast Jones will be concerned ahead of the four consecutive Tests at Twickenham.
“He will be be having nightmares. We have got a massive playing pool, but you are losing front-line warriors,” Monye said.
“The back row, which used to be an area of strength, is starting to look pretty bare. I am genuinely scratching my head.
“The whole dynamic of the back row massively changes now.”
Jones names his squad for the autumn internationals at 09:30 BST on Thursday.