Henry Slade has had surgery on a leg injury suffered in Exeter's win over Wasps at the weekend.
The England centre was forced off with 15 minutes remaining of the 41-27 win at the Ricoh Arena and although Exeter have not confirmed he suffered a broken leg, the injury was deemed serious enough to require an operation.
It is also likely to rule him out of England's Six Nations plans under new coach Eddie Jones and will be a major blow to Exeter, who temporarily took top spot in the Aviva Premiership before Saracens' win at Newcastle on Sunday.
Slade has won two caps for England after making his debut before the World Cup against France in August.
He then started Stuart Lancaster's final pool match against Uruguay, but now joins Northampton prop Alex Corbisiero (knee surgery) in facing a race against time to make Jones' first Six Nations tournament.