Valtteri Bottas says he is not worried he could lose his seat after 2019.
The Finn is all signed up for next year, but Mercedes could be holding the seat open for Force India refugee Esteban Ocon for 2020.
Ocon, the top Mercedes junior who looks set to be a 'super reserve' for all the Mercedes-powered teams next year, insists he has been given "no assurances" for 2020.
But Bottas at least admitted he has to up his game, calling 2018 with Mercedes "my worst formula one season".
"For sure the first season with Williams was difficult, but you can't compare that to now," he said.
"2017 felt different to this. I was the new guy and still I remember how disappointed I felt here a year ago," Bottas said in Abu Dhabi.
"Looking back now, I realise I did win a few races. So I'm even more disappointed now," he added.
At the same time, Mercedes team boss Toto Wolff sounds bullish about Ocon's future, which would seem to suggest that the seat for 2020 is up for grabs.
Asked if he is worried, Bottas said: "No. In formula one there is all sorts of talk, and it's only natural that every driver wants to use every opportunity.
"But it's not my job to worry about that. I have an excellent relationship with everyone on the team, including Toto. We hide nothing from one another.
"If next year I achieve my goals and the goals of the team, then everything will be fine. If not, the team will rightly decide that I am not performing well enough.
"That's the way it should be in sports," said Bottas.
