Real Madrid striker Kylian Mbappe is a doubt for the El Clasico against Barcelona next month because of a hamstring injury.
The France captain was replaced after 81 minutes of the 1-1 La Liga draw with Real Betis on Friday.
Real said Mbappe had been "diagnosed with an injury to the semitendinosus muscle in his left leg" and that they were "awaiting progress".
Real, who are 11 points behind leaders Barcelona in the table with five games remaining, visit Espanyol on Sunday before travelling to the Nou Camp on 10 May.
They were knocked out of the Champions League by Bayern Munich last week and face the prospect of a trophyless season.
Mbappe, who missed almost a month earlier this year with a knee issue, has scored 24 goals in 28 La Liga games and 15 goals in 11 Champions League matches this season.
The World Cup in the US, Canada and Mexico starts on 11 June.