England duo Jonny May and Billy Vunipola are major doubts for Saturday's Twickenham Test against Fiji after they didn't take part in training on Thursday morning.
Gloucester wing May, who scored a try in last Saturday's win over South Africa, has been working with Vunipola and Mike Brown in the indoor facilities at Pennyhill Park.
Eddie Jones was due to name his team to face Fiji at 10am but the England coach has put that back to 2.30pm.
Vunipola suffered an upper body injury against the Springboks, although he did return to training on Tuesday, while Brown is expected to be rested with Alex Goode slotting in at full-back. But May's absence will force a further rejig to England's back three.
"If Jonny May is out of this game it is a real shame," said Sky Sports commentator Miles Harrison.
"He has just returned internationally after nine months out with a knee injury and was so sharp. He's a real asset and scored a good try against South Africa.
"It'll be a shame if he misses out but it will be somebody else's opportunity."
Semesa Rokoduguni is expected to win his second cap against his native Fiji, two years after making his debut, while Elliot Daly could move from centre to the wing with Jonathan Joseph returning to the midfield.
"It will be a very special moment for Rokoduguni to return after that two-year gap," said Harrison.
"He made his one and only appearance against New Zealand and didn't disgrace himself by any stretch of the imagination, but just drifted out of the picture under Stuart Lancaster.
"This is a testament to his return to form and I think he has been the form winger in the Premiership this season. He is thoroughly deserving of his recall for Marland Yarde.
"As far as Elliot Daly is concerned, in the immediate aftermath of last Saturday's game Eddie Jones said they would look at him on the wing with Jonathan Joseph at 13.
"That's something England would have been considering, even without the potential injury to Jonny May."