England captain Owen Farrell is a doubt for the Six Nations after suffering an injury in training.
The versatile Farrell has not played since November after undergoing ankle surgery he required due to damage done during a 32-15 victory over Australia at Twickenham.
Farrell was due to feature for Saracens in their European Challenge Cup clash with London Irish on Sunday, but the 30-year-old has suffered another setback.
Sarries said in a statement: "Owen was back in full training having recovered from the ankle injury he sustained against Australia during the Autumn internationals.
"We will have a further update after he sees a specialist early next week."
Farrell's place in the England side has been called into question, but Eddie Jones this week firmly backed his skipper after naming his squad for a Six Nations tournament that the Red Rose start against Scotland at Murrayfield on February 5.
"We believe Owen can get into his best form very quickly and we believe he will be right to play against Scotland," the England head coach said.
“We are hopeful he's going to play this weekend. He has got a good training week with us next week and we will know whether he is right to play. We will just have to wait and see how he goes over the next couple of weeks.
"He's the best person to captain the team. Very clearly, he's the best person in my judgement to captain the team.
"If he's fit and eligible for selection, he will captain the team. If he's not then we will make an adjustment to that."
Courtney Lawes would appear to be the most likely player to take over as captain after leading his country in a win over South Africa in the absence of Farrell.