Owen Farrell is a doubt for England's Calcutta Cup clash with Scotland after suffering a knee injury in training.
Farrell was confirmed at inside centre in England's starting XV for Saturday's clash at Twickenham on Thursday morning but he failed to make it to the end of their training session.
The Saracens man left the session early and team medics appeared to be looking at his left knee before he walked away while his team-mates continued to prepare.
Head coach Eddie Jones conceded at his press conference that Farrell might be a late withdrawal from his side, although England do have another centre - Worcester's Ben Te'o - among their replacements.
"Yeah, he could be in doubt. He's got a bad knee and he couldn't finish training," Jones said before joking that Farrell had "run into his dog".
"Owen just ran into someone at training - it's as simple as that. He'll be alright, possibly.
"I'm not going to tell you that (the specifics of Farrell's injury). I'm sure you've got a long range camera and you can go into one of the rooms and find out.
"We've got some great goal kickers - George Ford. But Owen will be right, he's in doubt but we'll see. He should be right.
"I think he will be alright but we've got many back-ups. Ben Te'o could play 12 and he is an exceptional player so there is no risk for us."