England number eight Billy Vunipola is major doubt for the 2003 champions’ Pool C decider against France on Saturday.
The Saracens back rower has been a key figure in the England set-up this year, but was forced off at half-time in the 39-10 victory over Argentina on Saturday with a twisted ankle.
The 26-year-old is set for a scan on Tuesday ahead to assess the extent of the injury ahead of the crucial pool decider against France in Yokohama on Saturday (EXCLUSIVELY LIVE on eir sport 1 from 8.30am).
However, head coach Eddie Jones and his team are confident that they have ample cover should Vunipola fail to recover in time.
"We will have a clearer picture tomorrow. He's having a scan as a precaution," England scrum coach Neal Hatley said.
"He's walking around with a smile on his face - but it's nearly lunchtime so he's happy.
"We plan for all eventualities and we have played a lot of rugby without the Vunipolas.
"Billy is an important figure for us, but other people pick up the slack - we've got like Ellis Genge, Mako Vunipola, Maro Itoje, Courtney Lawes and Kyle Sinckler."
England’s other injury concern for the game is prop Joe Marler with a suspected hamstring issue, although Hatley insisted that it was less serious than first thought.
"He has done training this morning and he has played a lot of rugby for us and it's a position we have good strength in, and we will see how he pulls up to make sure we put out the strongest team possible," Hatley said.
"There's a little bit of (pain) referral in his back and we will see how he is tomorrow."
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