Karim Benzema became the highest French goalscorer in history on Monday after his double gave Real Madrid a 3-0 win over Mallorca, sending them 10 points clear at the top of La Liga.
But the Frenchman had to go off late on with what looked like an injury in his lower left leg, giving Madrid a serious headache before Sunday's Clasico against Barcelona.
Vinicius Junior, who opened the scoring, and Rodrygo also suffered problems in the second half.
"We will look at it in the next few days," said Madrid coach Carlo Ancelotti.
"They don't seem like very serious things. Rodrygo was a knock, Mendy has felt something in his adductor and Karim, after a jump, didn't feel good. We'll see if they can recover for Sunday."
Benzema's absence for the game at the Santiago Bernabeu would come as a serious blow to Madrid, after the striker continued his scintillating recent run with two more goals at Son Moix.
After scoring a hat-trick to help Madrid defeat Paris Saint-Germain 3-1 in the Champions League last week, the 34-year-old's penalty against Mallorca took his career tally to 412 goals, putting him one above Thierry Henry in the all-time list of French scorers.
