Speculation has been rife that the Spanish giants were closely monitoring the 21-year-old, and in a press conference on Monday, coach Ancelotti revealed that to be the case.
"We have interest in Lucas Silva, but he is not the only player - there are also others that we are interested in," he said ahead of Real's UEFA Champions League game against Ludogorets on Tuesday.
"If we need it, we will take the decision after the Club World Cup [later this month], evaluating what is happening with our injured players.
"I think that in this sense, we have to wait for the Christmas period.
"[Luka] Modric and [Sami] Khedira's recoveries will become more clear and then in this period, we will see."
Khedira missed Saturday's 3-0 win over Celta Vigo after suffering a blow to the head in last week's Copa del Rey meeting with Cornella, and Ancelotti said the German's recovery needs to be treated with patience.
"Khedira has a blow on the head and it is not so simple," he said.
"Really, he has had bad luck, because he started to play [after a succession of injuries] and now it is a new low.
"We hope that the new year is better for him."
Another player working his way back from injury is Jese Rodriguez, who tore his anterior cruciate ligament in March but made a goalscoring return from the bench against Cornella.
"We are following the programme of work with Jese," Ancelotti said.
"Tomorrow he will play not from the outset. He will need minutes. He begins to have a good condition and early next year he will be 100 per cent."
