Ronaldo ruled out of Portugal qualifiers
The forward took a knock to his right ankle in Real Madrid's 0-0 draw at Real Mallorca yesterday.
He underwent an MRI scan this morning that revealed "a contusion on his right ankle," the club revealed in a statement.
"He will be unavailable for an estimated period of approximately three weeks," added the statement.
Portugal play Cyprus on Friday and Norway four days later.
Ronaldo is also likely to miss Real's next two La Liga matches, as well as their first UEFA Champions League group phase match at Ajax on 15 September.