Cristiano Ronaldo could miss an important part of Real Madrid's season with the thigh injury he sustained against Villarreal on Wednesday.
The Los Blancos forward left the pitch in the closing stages of his side's 3-0 win at the Santiago Bernabeu after attempting an overhead kick, which led to the muscle strain.
Real manager Zinedine Zidane played down fears after the match that the problem was serious, while Ronaldo also suggested it was a minor issue.
But subsequent scans have revealed the extent of the injury, which will rule the Portuguese star out for the La Liga trip to Rayo Vallecano on Saturday and puts his participation for Tuesday's Champions League semi-final, first-leg clash with Manchester City in doubt.
Ronaldo's 31 goals have taken the Madrid giants to within a point of the league summit in third place, while he currently leads the 2015/16 Champions League scoring charts with 16 strikes.
A statement on the club's official website read: "Following tests carried out today on Cristiano Ronaldo, he has been diagnosed with a muscle strain in his right thigh. His recovery will continue to be assessed."