Billy Vunipola could miss England's Six Nations campaign after it was confirmed he suffered a broken arm during Saracens' Champions Cup match against Racing 92 on Sunday.
No.8 Vunipola, who featured in every game in England's run to World Cup final last year, was injured during the early stages of Saracens' 27-24 victory and was withdrawn in the sixth minute at Allianz Park.
Although no time frame has been given for his return, Vunipola is unlikely to play any part in the forthcoming Six Nations.
"Billy will see a consultant over the coming days to determine the full extent of the injury before undergoing rehabilitation," Saracens said in a statement.
England head coach Eddie Jones will name his Six Nations squad on Monday and will be monitoring Vunipola, who could be out with a serious arm injury for the fourth time in two years.
Vunipola's club future is also uncertain after it was confirmed Saracens will be relegated from the Premiership at the end of the season for persistent salary cap breaches.
Australian Associated Press