Real Madrid defender Dani Carvajal injured his right ankle during the 1-1 league draw at Atletico Madrid and is likely to miss Spain's crucial European Championship qualifiers.
A club statement on Monday revealed that tests on Carvajal at a Madrid hospital have diagnosed "an injury to the peroneal tendons" in his right ankle.
Carvajal, who has only missed one of Madrid's seven league matches this season, provided the pass that enabled striker Karim Benzema to score at the Vicente Calderon Stadium on Sunday.
The club did not say how long it expected the right back to be sidelined, but tendon injuries normally take two-to-three weeks to heal, meaning Carvajal will likely miss Spain's qualifying matches for next year's European Championship.
The first match is against Luxembourg on October 9 before they travel to Kiev to face Ukraine three days later.