The 26-year-old underwent a scan on Monday after injuring his ankle in Saturday’s 39-10 victory over Argentina, which booked England’s place in the quarter-finals with a pool game to spare.
Despite scrum coach Neal Hatley playing down the injury, Vunipola appeared in a protective boot at the team hotel, raising fears the injury could be worse than feared.
Although assistant coach Scott Wisemantel was unable to confirm the details of Vunipola’s scan, he did not appear at England’s training session besides the Tokyo Stadium, with the No 8 instead completing a “recovery and rehab” session away from the squad.
“At this stage all 31 players are available and we will make a call late Wednesday early Thursday, but if there is any doubt we will rest him,” Wisemantel said.
The attack coach added that the protective boot on his left foot was more precautionary than anything more serious.
“We are being overly cautious, and if there is any risk that Billy is not going to be 100 per cent we will rest him,” added Wisemantel, who added that there are currently no concerns over his participation in the quarter-finals on the weekend of 19/20 October.
Captain Owen Farrell also missed training on Tuesday along with Jack Nowell, though Wisemantel is confident England will continue to have 31 players to select from to face France, even if they choose to stand Vunipola down for the weekend.
The Saracens forward has started all 12 England tests this year, which led to calls for him to be rested at some stage of the tournament given his previous injury record. But having been selected to start against the Pumas, Vunipola twisted his ankle in a tackle by fly-half Benjamin Urdapilleta, and after having his foot taped up for the remainder of the first half he did not reappear for the second.
Wisemantel also addressed the weather threat facing England this weekend, with Typhoon Hagibis currently forecast to bring the worst weather of the season to the capital on Saturday.
The Typhoon was due to hit the south of the island where Ireland play their crucial final pool game against Samoa in Fukuoka, but a shift in wind direction looks set to bring the worst of the weather to Tokyo and Yokohama, where England face France on Saturday and Japan play Scotland on Sunday.
World Rugby have put provisions in place to move the games if necessary – with a decision needing to be made more than 48 hours before kick-off – but Wisemantel accepted there is little England can do about the threat.
“Regarding the typhoon we have no control over the weather and we have to prepare for the game and see how it goes,” he added. “Regarding the permutation around the game and shared points we are just concentrating on playing to win.
“I live in a bubble and I don’t know where the game would be played. One thing I have learnt in Japan is that they prepare for the worst and then usually it doesn’t eventuate.”
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