Carlos Sainz has admitted that he will probably have to leave the Red Bull fold if he is to move further up the grid.
The Spaniard has been retained by Toro Rosso for 2017 but is unlikely to gain a promotion to Red Bull Racing in 2018 with both Daniel Ricciardo and Max Verstappen tied to the multiple world champions for a number of years.
"Unfortunately for me, they look pretty happy with the pair they have," said Sainz. "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. It would be a great pleasure, if not I’m sure they will understand I cannot spend my life being the third one."
The former Formula Renault 3.5 champion was set for a move to Renault next year, only for Red Bull to put a halt to any potential deal. Now Sainz has said that the energy drink firm wouldn't stand in his way if he wanted to move on after 2017.
"It depends 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," he said. "At the end they perfectly understand I have high targets, important targets in my mind for 2018 and it will be discussed."
Bahrain International Circuit - Winter testing