Real Madrid forward Kylian Mbappe faces a spell on the sidelines because of a thigh injury.
The France international, who joined the Spanish club in the summer after his contract with Paris St-Germain expired, scored in a 3-2 win against Deportivo Alaves on Tuesday before being substituted after 80 minutes.
Speaking after the game, Real Madrid coach Carlo Ancelotti said: “He’s fine, a little overloaded, he asked me for the change to avoid problems.”
In an update on Wednesday, Madrid said that “following tests” the 25-year-old “has been diagnosed with an injury to the biceps femoris in his left leg” and “his progress will be monitored”.
Real Madrid are away in a league match at Atletico Madrid on Sunday and then play Lille in the Champions League and Villarreal in the Spanish top-flight prior to the October international break.
Mbappe had scored six goals in seven games for the Bernabeu club before sustaining his injury.