The Mexican explained he "got a call from Lawrence [Stroll] and he told me yesterday [Wednesday] they were going into another direction".
Pointed out to Perez that only recently he had said that he felt his seat was not under threat, he added: “That was the feedback I was getting, that everything was looking [good] that the team wanted to keep me.
“There were some discussions in the background about contracts and so on that I’m not willing to disclose because I think those things should remain between the team and myself. There were a couple of things in the contract that we went through.
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“In the end, they just officially told me yesterday that I am not continuing. I didn’t expect that. But it is how it is.”
With the team improving its competitiveness and starting to push the front-running teams, Perez is naturally gutted to be leaving at such a promising time.
"I know that I am leaving a great car," said Perez. "They are looking great for next year. Definitely the team will be stronger next year than this year.
"In that regard, it hurts a bit more knowing you are leaving a good car but you never know in the future. Things in Formula 1 change so quickly, let's see what the future holds for both of us."
Addressing his future further, he said: "I think everything is an option right now. My main target is to stay in Formula 1.
"I feel I am still very young and hungry and I want to carry on in Formula 1 but it has to be the right package, a package that gives me the maximum motivation to give 100% every single lap and I think it is also got to be a long-term project targeting 2022."
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