The Manchester City striker has often spoken of his desire to play for Los Blancos despite having already featured for their city rivals Atletico Madrid in his career.
"El Kun would be the solution for Madrid's future, a perfect complement for Ronaldo," Maradona told Marca. "Sergio is pure movement, while [Karim] Benzema and [Gonzalo] Higuain are two impressive tanks who can pull around the defence for you, but who clash with CR7.
"One of these days Cristiano is going to carry off one of those two. Sometimes I think they are going to need to put in traffic lights to organise the traffic between them.
"Kun would create spaces for Ronaldo. It would be spectacular. I continue to see him at Madrid, although the truth is at the moment he is very happy at City, very happy with the club. Having said that, living in Manchester is like living in a freezer."
Aguero split up with Maradona's daughter Giannina in January.