Exeter Chiefs flanker Tom Johnson could miss out on England's RBS Six Nations Championship campaign through injury.
The 30-year-old was taken off the field on a stretcher during the Chiefs' Heineken Cup match with Leinster on Saturday after just 15 minutes. He will be medically assessed over the course of this week, but could be a doubt for England's opening Six Nations match against Scotland on February 2.
Exeter head coach Rob Baxter said: "We won't know exactly how serious the damage is until he has a scan. It looks like it is his knee and ankle, more of a twist than anything too serious. It is ligament damage."
Matt Kvesic of Worcester Warriors was added to the England squad last night as cover for Johnson, whose injury failed to detract from an excellent performance by the Chiefs.
Exeter lead the defending champions 17-12 at half-time. The Irish side, who were eliminated from the competition yesterday following Munster's victory over Racing Metro Paris, were pushed hard before earning a 29-20 win at Sandy Park.
Leinster head coach Joe Schmidt was full of praise for the Devon side. He said: "I have got a lot of respect for Exeter, they put a lot of pressure on us at the breakdown.
"They didn't allow us to get a lot of flow. I just felt we had to go a little bit more directly at them. They have a tight five that work incredibly hard and that allows them to spread the width of the field. You have to go direct at them and mix your game up."
In another England squad update, Mouritz Botha of Saracens has been called up to cover for Northampton Saints' Calum Clark, who has a shoulder injury.