Frederic Vasseur, the new team boss at Renault, has admitted that neither team driver has a guaranteed future with the French marque beyond 2016.
"Both drivers have a contract for one season," he is quoted as saying by Danish broadcaster TV2.
"Formula 1 is moving all the time and you can't say your drivers are staying for five or six years. Right now for us it's more about building a strong base."
After taking over the near-collapsed Lotus at the eleventh hour, Renault is keeping its expectations very low for the 2016 season.
"We are in the battle around the points," Magnussen said at the Barcelona test on Tuesday. "Maybe just outside the points. I think if we get both cars in the points in Melbourne, that will be a really good weekend."
However, although Vasseur said that although 2016 will not be about winning, that does not mean the drivers are unimportant for Renault.
"It is very important that you have the right drivers, as the whole team is of course built on them," he insisted. "But first and foremost we need to deliver a car that they can do [good] results with.
"It has to be in the right order."
The season gets underway with the Australian Grand Prix in just over two weeks' time.