Shoulder surgery rules Chris Robshaw out of RBS 6 Nations campaign
Chris Robshaw will miss the entire RBS 6 Nations with a shoulder problem that further deepens England's injury troubles.
The 30-year-old flanker was due for surgery on his left shoulder on Monday, with Harlequins expecting him to be sidelined for three months.
England must already do without talisman number eight Billy Vunipola for at least the Six Nations' early rounds, while captain Dylan Hartley will be short of match-sharpness after his six-week suspension.
Joe Marler, Mako Vunipola and James Haskell are all further injury doubts, though locks George Kruis and Joe Launchbury hope to ready for England's Six Nations opener against France at Twickenham on Saturday, February 4.
"Chris Robshaw will undergo surgery on his left shoulder today to repair an injury sustained in the match against Worcester Warriors on New Year's Day," read a Harlequins statement.
"He is expected to be out of competitive action for around 12 weeks."
Robshaw forged himself a new lease of Test-match life as England romped to a perfect 13 wins in 2016 under new head coach Jones.
The 55-cap flanker relinquished the captaincy after England's failure at the 2015 World Cup, but has fought his way firmly into taskmaster coach Jones' starting line-up.
England will open their Six Nations title defence by hosting France at Twickenham - and must now do without linchpin duo Robshaw and Saracens number eight Billy Vunipola.
Robshaw suffered his shoulder injury in Harlequins' 24-17 Aviva Premiership loss at Worcester on New Year's Day, attempting to play through the pain before eventually being forced off.
Jones will be forced into a major back-row reshuffle, and might also be without Wasps flanker Haskell.
Haskell lasted just 35 seconds of his comeback after toe surgery in Wasps' 22-16 victory over Leicester on Sunday, suffering a concussion on tackling Freddie Burns.
Wasps boss Dai Young insisted Haskell was "totally fine" after the Ricoh Arena match, but the luckless 31-year-old must now undergo concussion testing before being cleared for a return to action.
England boss Jones could well deploy Saracens sensation Maro Itoje at blindside flanker to offset Robshaw's loss, while fit-again Leicester flanker Mike Williams is another back-row option.
Harlequins prop Marler has been struggling with a calf problem, while Mako Vunipola is still recovering from a knee issue.
Saracens lock George Kruis has a minor cheekbone fracture, but has already targeted a return to action in the European Champions Cup clash with Toulon on January 21.
Wasps lock Joe Launchbury is carrying a calf issue but that is understood to be far less problematic than first feared.
Captain Hartley will be available for the opening clash against France, but will only just have served his six-week ban for striking Leinster's Sean O'Brien.
Jones must therefore weigh up whether the Northampton hooker will be match-hardened enough to feature against France.