According to reports in Spain, the 13 times UEFA Champions League winners are monitoring the defender, who has a 12 million Euros release clause ahead of a potential switch.
Their rivals Atletico Madrid have already established contacts with the 20-year old, who is having an outstanding campaign in La Liga this season.
Having broken into the Real Valladolid first this season, the youngster has attracted interest from Europe’s top clubs including Manchester United.
It is understood that Real Madrid’s excellent relationship with Real Valladolid will give them the edge ahead of their local rivals.
The Ghanaian defender has started every league game this season except against Barcelona at Camp Nou, where he started on the bench but came on after 32 minutes for the injured Nacho.
His numbers have made him one of the stand-out players at the Estadio José Zorrilla this season.