Mirco Bergamasco has been told he will miss up to five months after fracturing his knee cap in Italy's loss to Australia yesterday.
The winger and centre has undergone surgery to help repair the damage.
The Italian Rugby Federation has said that it expects the 29-year-old to be out for four to five months.
As a result, Bergamasco is likely to miss next year's Six Nations, which takes place in February and March.
Although he plays mainly on the wing or at inside centre, Bergamasco is Italy's regular goal kicker.
