Billy Vunipola is a major doubt for England's Six Nations campaign after sustaining a suspected broken arm on Sunday.
The number eight went off in the sixth minute of Saracens' 27-24 victory over Racing 92, a result that proved sufficient to ensure the week in which it was confirmed they would be demoted from the Premiership after breaching salary cap rules ended with progression to the European Champions Cup quarter-finals.
Vunipola has previously broken his right arm twice and his left arm once in the past two years and looks set to miss out on a place in Eddie Jones' Six Nations squad, which is set to be announced on Monday.
"They suspect a broken arm," said Saracens director of rugby Mark McCall. "I hope it's not. I don't think it's been confirmed yet."
The 27-year-old featured in every England game as they finished as 2019 Rugby World Cup runners-up to South Africa.
England begin their Six Nations campaign away to France on February 2.