Toro Rosso driver Carlos Sainz insists he's happy to be staying with the team for another season, but admits that he's worried about what his future might hold if there's no opening at Red Bull in 2018.

"Unfortunately for me they look pretty happy with the pair they have," said Sainz when asked if he still saw a race seat Red Bull as a realistic possibility for his future.

"Knowing Red Bull and myself that this is an important year [in preparation] for 2018. That is where I would definitely like to do a step in my career so we both know it, we both took that decision - unless they massively change their mind, there’s nothing anymore to do.

"They need to understand that obviously it’s good to have a third driver like me waiting there in case something happens, but I cannot spend my whole life being the 'just-in-case' option for Red Bull.

"They understand this and I’m convinced they know, that’s why next year is an important year for me to hopefully create a good base and move up if Red Bull is willing to take me.

"Obviously it would be a great pleasure [to get a chance at Red Bull]. If not, I’m sure they will understand I cannot spend my life being the third one.

"At the end together with Red Bull we take the decision of doing one more year in Toro Rosso, knowing very well that this is a very important year for myself.

"Yes they have an option obviously they can execute whenever they want but I will play an important role and will also decide it, it will not all be about them," he cautioned.

"It depends obviously on them if they want to exercise that option but it will also depend on me if I also want to do another year in Toro Rosso.

"At the end they perfectly understand I have high targets, important targets in my mind for 2018 and it will be discussed. Like everything in life, like every contract in every Formula One driver."

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