"Mako's got a calf injury, so it looks like it's going to be around six weeks," Mark McCall, the Saracens director of rugby, said.
"It's a tear in his calf. Nick will be around eight weeks with a syndesmosis injury of his ankle. That doesn't require surgery either, and it will be eight weeks. It is what it is, isn't it?"
The loss of Vunipola will be felt acutely. Not only does the 27-year-old rank among England's few world-class players, but Jones is painfully short of options in the loosehead department following Joe Marler's retirement from international rugby and injuries to Ellis Genge, Matt Mullan and Beno Obano. No other current English loosehead has started a Test.
Alec Hepburn, who made two replacement appearances in last year's Six Nations, is the next cab on the rank while Exeter teammate Ben Moon and Gloucester's Val Rapava Ruskin should come into the equation for the opening Test against the Springboks at Twickenham on November 3. Bath's Nathan Catt and Harlequins' Lewis Boyce have also featured in previous training squads.
Vunipola suffered the injury in Saracens' 13-3 Heineken Champions Cup win away to Glasgow in which his brother, Billy, also broke his arm and Isiekwe was injured. McCall assigned their losses to "bad luck", which in the case of No 8, Billy, seems particularly cruel. This is the third time that Vunipola has broken his arm this year, which has limited the 25-year-old to this two England appearances.
After undergoing surgery, Saracens expect him to be out for between ten to twelve weeks and hope he will be back in action by mid January. That it was his left arm that was broken rather than his previously troublesome right proved the smallest crumb of comfort.
"I think he's struggling, he's devastated," McCall said. "I feel for him. We all hope his luck will change. You've got players who are very important players in the club. We existed without Billy for almost the whole of last year, if we're honest. Billy understands Duncan's (Taylor, who ruptured his ACL) injury is way worse than his, season-ending."
Like his brother, Vunipola's injury is compounded by the absence of his usual stand-ins with Exeter's Sam Simmonds out for up to nine months with an ACL injury and Nathan Hughes facing a lengthy suspension. Hughes' original disciplinary hearing for allegedly punching or striking Gloucester flanker Lewis Ludlow in a Gallagher Premiership match was adjourned after he tweeted "what a joke" during the proceedings. As the reconvened hearing got underway on Wednesday night, Hughes is certain to receive a hefty ban. There is nothing that irks disciplinary panels more than their processes being called into disrepute.
Jones did receive a rare slither of positive news after Saracens centre Alex Lozowski received a two-week ban for a dangerous entry of a ruck against Glasgow which will leave him free to play in all four Tests while Maro Itoje and Jamie George, who both sustained broken noses in the fixture, are fit to play this weekend against Lyon.
Even if not all of the 16 absentees are frontline players, Jones will still be missing at least six first-choice players. He will need to employ all his coaching nous, not only to fill the sizeable gaps left at No 8 and loosehead but also to solve the near impossible task of replicating the ball-carrying impact that the Vunipolas bring.
It appears that Jones is leaving many of the decisions over his 36-man squad until the last minute with many players on the periphery of selection such as Gloucester fly half Danny Cipriani and Exeter flanker Don Armand still awaiting notification of their fate. However, Sale Sharks Chris Ashton is set to be selected despite not playing a competitive match this season, having served a seven-week suspension for a tip-tackle in a pre-season friendly.
England's walking wounded | Players unavailable to Eddie Jones
PROP
Mako Vunipola (calf) - 57 tests
Ellis Genge (knee) - 5 tests
Beno Obano (knee)
Matt Mullan (knee) - 17 tests
LOCK
Joe Launchbury (knee) - 54 tests
Jonny Hill (hand)
Nick Isiekwe (ankle) - 3 tests
BACK ROW
Billy Vunipola (arm) - 36 tests
Sam Simmonds (ACL) - 7 tests
Nathan Hughes (expected ban) - 17 tests
Jack Willis (knee)
Chris Robshaw (knee) - 66 tests
SCRUM-HALF
Dan Robson (ankle)
CENTRE
Jonathan Joseph (ankle) - 40 tests
Ben Te'o (thigh) - 15 tests
WING
Anthony Watson (Achilles) - 36 tests
Marland Yarde (knee) - 13 tests
... and ... Joe Marler (prop, retired) - 59 tests
- With The Telegraph
