Paul Pogba reportedly remains a target for Madrid, who are keen to bring the United star to the Santiago Bernabeu before the European transfer window shuts on September 2.
United are believed to want close to the world-record €222million fee Paris Saint-Germain paid Barcelona for Neymar in 2017.
Mathias Pogba – Paul's older brother who plays in the fourth tier of Spanish football – was asked about the French World Cup winner's future.
"I don't know, I'm not inside the Bernabeu. In football you never know," Mathias Pogba told AS when asked if a move to Madrid is still possible.
"He is very well, as always. No one expects me to say something bad about United. He is a professional and his present is there.
"The future? It depends on the clubs: that Manchester wants to sell and that Madrid wants to buy. This is business.
"Everyone knows that my brother could use Real Madrid and Zidane. Those who have to talk are Madrid and Manchester United."
"I don't know what to say ... Zidane has always spoken well of my brother, it's an honour," he continued.
Paul Pogba, who arrived from Juventus in 2016, has tallied two assists in three matches for United this season.
The 26-year-old set up two goals in United's 4-0 rout of Chelsea in their Premier League opener, while he missed a penalty in a 1-1 draw at Wolves on August 19.
United were stunned 2-1 by Crystal Palace last week to be left with four points from three matches to start the season.