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.