"The negotiations didn't happen at the right time," Olhats said.
"There was a form of negligence."
Olhats believes that the manner of Griezmann's farewell cost him the send-off he deserved.
"Antoine would have deserved a more dignified exit and it's his and his representatives' fault," he said.
"I understand that you want something new after five seasons at the same club.
"But this didn't stop me believing in his sincere fondness for Atletico.
"Antoine isn't a bad kid, it's simply about not looking back."