Real Madrid have confirmed goalkeeper Keylor Navas has sustained an adductor injury.
The Costa Rica international is reported to have suffered a relapse of the problem he picked up during the international break.
The 30-year-old missed the 2-1 La Liga win over Getafe last weekend but returned for the midweek Champions League clash with Tottenham, making a crucial save from Harry Kane in the 1-1 draw at the Santiago Bernabeu.
Madrid released a statement on Friday confirming he has a thigh problem but would not specify how long he is expected to be sidelined.
However, reports in Spain suggest he could be out of action for up to two weeks, making him a doubt for the return fixture against Spurs at Wembley on November 1.