Iker Casillas has admitted his admiration of Sergio Aguero but is unsure if the Atletico Madrid star should move across the Spanish capital.
The 23-year-old striker has been linked with a host of Europe's top clubs, with city rivals Real Madrid being touted as his most likely destination after coach Jose Mourinho stated his interest.
Casillas, 30, is well aware how fierce the Madrid rivalry is having been at the Bernabeu his entire career.
And although the Real keeper can see why Aguero is attracting plenty of interest, he remains cautious over the likelihood of a cross-city switch going through.
"I do not think it would be comfortable or easy to make a move in the Spanish capital and go from Atletico Madrid to Real Madrid," he said.
"Right now, Aguero is one of the three or four players who are a little bit higher in the world of football.
"He is very young, determined and talented. He is being followed by many great teams."