Northampton Saints have confirmed that Ben Foden has suffered "significant damage to his ankle ligaments".
The England international suffered the injury during his side's 18-15 victory over Bath Rugby on Friday evening.
He will now visit a specialist tomorrow, where he will be told how long he will be out of action for.
Nevertheless, the Saints have revealed that they expect the 27-year-old "to be out of action for a number of weeks".
Foden joined the Saints from Sale Sharks in 2008.