IRELAND left wing Keith Earls is certain to miss Munster's first two Heineken Cup matches with medial ligament damage.
The scan revealed sufficient damage to rule him out for between four and six weeks. He will miss out on Saturday's Thomond Park appointment with last season's beaten finalists, Northampton Saints, and an away date at Castres the following week.
The next two rounds away and at home to The Scarlets are also in jeopardy. Earls was forced off in the first minute of the Leinster v Munster League match last Friday.