London - England number eight Ben Morgan could be doubtful for the Six Nations after being carried off and given oxygen during Gloucester's dramatic 24-23 win over Saracens in the Premiership at Kingsholm on Friday.
The 25-year-old, who has 27 caps and was one of England's best players during the autumn tests, injured his left leg early in the second half of a nail-biting match won by James Hook's 50m penalty in stoppage time.
England's Six Nations campaign begins with a trip to Wales on February 6 with Morgan a major doubt amid British media reports that he may have suffered a fracture.
"When you see someone coming off on a stretcher it's never a good sign," Gloucester director of rugby David Humphreys was quoted as saying by the BBC.
"All I know at this stage is it's a lower leg injury, I'm not sure of the extent. That's something we will probably not know until a medical review tomorrow and then see a specialist as early as we can next week."
Referee JP Doyle stopped the game after Morgan was tackled just short of the Saracens line and the player was treated for several minutes before being carried off the field.