Sunderland have revealed they will not know the full extent of Kenwyne Jones' knee injury until he has had several weeks of treatment.
The 23-year-old picked up the problem in action for Trinidad and Tobago against England at the start of the month.
He clashed with England goalkeeper David James and returned immediately to Sunderland for tests, which revealed ligament damage.
He will now undergo what the Black Cats describe as 'conservative treatment' before the injury will be assessed again.
A statement released on Sunderland's official website read: "The club arranged their own radiological investigations and have detected ligament damage, which will require several weeks of conservative treatment.
"After this period, a further assessment will be undertaken to assess the full extent of the injury."
Manager Roy Keane will hope for good news when the next scan takes place having admitted his side relied heavily on last summer's £6million acquisition.
However, reports have suggested that Jones could miss the start of pre-season training.