Eric Boullier has admitted McLaren is looking to eventually "refresh" its driver lineup.
It is rumoured strongly that, ahead of the start of its works Honda partnership, Woking based McLaren is seeking a top driver to spearhead the project, such as former team racers Fernando Alonso or Lewis Hamilton, or quadruple world champion Sebastian Vettel.
"I can only do my best and hope that is good enough," said Magnussen.
"Anyone at McLaren should feel that you have to deliver to your best to deserve to be there and that goes for me and Jenson as well."
It is believed that if McLaren does oust a current driver to make way for a newcomer, it would be the 2009 world champion Jenson Button, 34, who is out of contract.
McLaren supremo Ron Dennis made waves recently when he urged Button to "try harder".
"Jenson knows the important thing is to score as many points as he can," team boss Boullier is quoted by Britain's Mirror newspaper.
"He doesn't have to prove anything as he is a world champion and has won many races for McLaren.
"We need to be realistic as well, because in one, two, three years we may need to refresh our driver lineup and obviously we will be seeking the best drivers at that moment in time," he added.
For his part, Button - the second-oldest driver in F1 but even more experienced than Kimi Raikkonen - insists he intends to stay on the grid for a sixteenth consecutive season in 2015.
"Right now, my interest is to race in F1," he said.
"In F1 the emotions are all over the place -- it is highs, it is lows. I have lived my life like that for a long time and I want to continue my life like that.
"I am young and fast and enjoy what I do for a living, and I don't want that to change," added Button.
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