England fullback Ben Foden will be sidelined for several weeks after suffering an ankle injury during Northampton's victory over Bath last week.
Foden has severely damaged his ankle ligaments and, although he will see a specialist on Wednesday to determine the full extent of the injury, there is little doubt the Saints star will be out of action for some while.
"Ben Foden sustained significant damage to his ankle ligaments during last Friday's Premiership game against Bath, and he is going to see a specialist tomorrow," a Northampton statement said on Tuesday.
"The club will have more information after that, but Ben is expected to be out of action for a number of weeks."
Foden's injury is a major blow to Northampton, who have enjoyed an unbeaten start to their Premiership campaign with victories over Gloucester, Exeter and Bath.
The 27-year-old is unlikely to recover in time for Saints' European Cup opener against Glasgow next month, while news of Foden's injury will be of considerable concern to England head coach Stuart Lancaster.
England begin a tough Test schedule against Fiji at Twickenham on November 10, which is followed by clashes against Australia, South Africa and New Zealand.