England are nervously awaiting the full prognosis of the ankle injury sustained by Billy Vunipola against Argentina.
The key No8, who did not appear for the second half of the 39-10 victory, underwent a scan on Monday and appears very unlikely to face France on Saturday.
Both teams have already secured qualification for the quarter-finals, so England will not risk players. Eddie Jones has also suggested he could rotate his squad.
Assistant coach Neal Hatley said: “We will have a clearer picture tomorrow regarding Billy and then we will make a firm diagnosis.”
If Vunipola was unavailable to face France, Tom Curry — who filled in at No8 on Saturday — and Mark Wilson would be the main contenders to replace him.
Hatley said England have enough ball carriers to cover Vunipola if he does miss out. His brother, Mako, returned to fitness today.
“We plan for all eventualities and there are people to pick up the slack when Mako and Billy don’t play,” said Hatley.
“We have played a lot of rugby without them.”
Joe Marler also sat out full England training today, having looked in discomfort when being substituted in the second half against Argentina.
