Exeter Chiefs and England centre Henry Slade will be out for about four months after having surgery on his broken leg and damaged ankle.
It means Slade is likely to miss the Six Nations, which starts in February.
The 22-year-old, capped twice by England, was hurt during Exeter's Premiership win over Wasps on Saturday.
"It was a pretty major operation but certainly not one we don't expect him to make a full recovery from," head coach Rob Baxter told the club website.
"We are certainly not pencilling in any date for Henry's return because we know it is long term.
"We will start talking about a return date in eight to 10 weeks' time when we know a bit more - it will take a bit of time though and a lengthy rehab process."
Meanwhile, Chiefs have announced that back-rower Dave Ewers, 25, will miss "a fair few weeks" after suffering a knee injury.
"It is difficult to put a timescale on these things but he will be out for a significant period of time," said Baxter.