Aguero had scored 102 goals in 233 games for Atletico, who he joined for €22 million from Independiente as a teenager, before making a €45m move to City in summer 2011.

Atletico wanted City to pay at least €60m for Aguero, and the saga dragged on for two months amid a widespread feeling that the player had tried to force through a move to crosstown rivals Real Madrid.

"[Aguero] has been the only player who left Atleti under a cloud, as he was stupid," Cerezo told "El Partidazo de COPE". "He arrived as a hero, and he left through the back door."

Aguero has gone on to win two Premier League titles with City, but has recently lost his place in Pep Guardiola's team to Brazil international Gabriel Jesus, who was finally registered with the Premier League club last month following a £27m move from Palmeiras.

That has fuelled speculation the 28-year-old could be on the move again this summer -- with Real Madrid, Chelsea and Inter Milan reportedly among the teams looking to take advantage of the situation.