Henry Slade will undergo surgery on Sunday after suffering a suspected broken leg in Exeter's Premiership victory over Wasps.
The 22-year-old England centre was carried off midway through the second half of Exeter's 41-27 win on Saturday.
"Henry has an injury to the lower part of his right leg and it is envisaged he will be operated on today," said Chiefs director of rugby Rob Baxter.
"We have set no timescale on how long he will be sidelined for."
The injury raises the prospect of Slade missing England's Six Nations campaign starting in February, but Baxter said more would be known after the operation.
Baxter said the player was "in a cast and the initial prognosis is that it looks likely to be a broken leg".
Slade has won two caps for England, making his debut in the World Cup warm-up game against France in August before starting Stuart Lancaster's side's final pool match against Uruguay.
His injury came on the same day Northampton confirmed prop Alex Corbisiero is set to miss England's Six Nations campaign because he requires knee surgery.