Fin Smith could miss England's Six Nations opener against Wales next month because of a calf injury.
The flyhalf was withdrawn just hours before kick-off from the Northampton side that suffered a 50-28 European Champions Cup defeat at Bordeaux on Sunday.
Smith is now awaiting the result of a scan that will indicate when he might return to action.
Northampton director of rugby Phil Dowson has revealed the British and Irish Lions playmaker will be out for at least a fortnight, making it uncertain if he will be ready to face Wales at Twickenham on February 7.
Veteran flyhalf George Ford started three of England's four tests in November, but Smith was given the number 10 jersey against Fiji and was on the bench for the opening 25-7 defeat of Australia.
"Fin Smith is dealing with a calf strain," said Dowson. "We're still waiting to see how long that is from a scan point of view.
"It's probably minimum two weeks, but with a muscle injury it's hard to give a timeline beyond that.
"It's not months and months and he's not going to be back this weekend, so somewhere in between that."
Calf problems are also troubling Northampton and England fullback George Furbank.
The Saints are wary of rushing Furbank's return given he had a significant calf problem in 2025 and has not played since December 20.
"George has felt some tightness in his calves," said Dowson ahead of Sunday's final Champions Cup group match against Welsh side Scarlets.
"I don't think it's major but at the same time with the history he's had, we're going to play it very, very conservatively and be pragmatic.
"That's based on his injury record from last year and the different things that waylaid him."