Chelsea fullback Marcos Alonso is wanted back at Real Madrid.
Real president Florentino Perez feels star wing-back Marcelo's form is declining and wants to find senior competition for the Brazilian.
Real can count on Theo Hernandez, but Perez recognises Real coach Zinedine Zidane needs a more experienced alternative and they're discussed re-signing former Castilla defender Alonso.
Don Balon says Zidane is said to be frustrated with Marcelo and the Frenchman sees Alonso as a perfect replacement.
Real were held to a 0-0 draw against Atletico Madrid on Saturday night in La Liga.
The point leaves the Spanish giants 10 points behind their rivals Barcelona after just 12 games.