Both drivers have struggled on the French manufacturer's return to Formula One, driving a car mostly developed by the cash-strapped lotus team last year.
But Palmer believes that both he and Magnussen have done enough to prove that they should be retained, but the bosses at the Anglo-French team haven't noticed.
"Do I think they appreciate everything we've done? I'm not sure," he said. "Kevin has done some great races as well and he's proven in 2014 [with McLaren] what he can do in a good car.
"He finished second in his first race, he out-qualified Jenson [Button] over the course of the year. Now two years on we're both struggling because the car is not really there," added the former GP2 champion. "Neither of us probably have not got the credit we deserve in a difficult car. And that's spurred on by the fact that one of us will be replaced.
"The car has been tricky and we've both done well, with mistakes but at certain points we've been doing a good job."
Bahrain International Circuit - Winter testing