France centre-back Philippe Mexes will miss the rest of the season after damaging his cruciate knee ligament, his club Roma said on Monday.
The 29-year-old former Auxerre defender was forced off during Sunday's 2-0 Serie A defeat to Juventus.
The extent of the damage was discovered during tests on Monday and Roma said he will need an operation, which could take place as early as Tuesday.
After that he will need three or four months to recover, meaning he should at least be fit for the start of next season.
However, he could have played his last game for the club as his contract is due to run out at the end of the season and talks over a new deal have stalled amid rumoured interest from AC Milan.
His injury is a blow for the France team who have Euro 2012 qualifiers lined up against Belarus on June 3, Albania on September 2 and Romania four days later.