Atletico Madrid president Enrique Cerezo has criticised Sergio Aguero for the manner of his "stupid" move to Manchester City in 2011.
The Argentina international left for the Etihad Stadium for a reported EUR45million after a protracted transfer saga in which there were suggestions that he was trying to engineer a switch to Real Madrid.
Aguero has enjoyed a sparkling career in the Premier League, but his future has once more come under scrutiny following Pep Guardiola's decision to drop him from the City starting line-up in favour of youngster Gabriel Jesus.
When asked for his view on the 28-year-old, Cerezo responded that he was the only star player to leave Atletico in recent seasons amid notable ill-feeling.
"He's 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."
Atletico have seen a number of major players leave the Vicente Calderon in big-money deals in recent years, including Diego Costa, who left for Chelsea in 2014.
Costa was heavily linked with a return to Atletico last year and has since been backed to move to the lucrative Chinese Super League, especially after he was dropped from the Chelsea squad last month following an alleged row with manager Antonio Conte.
Cerezo, however, believes Chelsea have no desire to allow him to leave.
"It has been a while since I spoke to him. He is at a great club," he said. "It's said that he will go to China, but Chelsea will not allow him to leave."
Antoine Griezmann is the latest Atleti star to be linked with the Premier League, with Manchester United reportedly ready to meet his EUR100million release clause to bring him to Old Trafford.
Cerezo stressed last month that he expects Griezmann to stay at the club "for a few years" and he remains defiant over his future.
"He has a contract with Atletico Madrid," he said. "Every time I see him, I give him a hug. He's a great player."
Cerezo added that he fully intends to offer veteran striker Fernando Torres a new contract, despite speculation that he will be allowed to move on.
"Everyone loves him. He's a great player. Why wouldn't we renew his contract?" he said.
"We'll talk about a renewal in due course. Atleti need great players."