Hans-Joachim Stuck doubts Mercedes can turn its 2011 car into a winner.
"Maybe we need to rethink the concept of the car," team boss Ross Brawn, referring to the W02 that was off the pace in Melbourne and Malaysia, is quoted by TZ newspaper.
The Briton, however, admitted the limitations of such an approach.
"We need to consider how we can engage in the battle for the lead," said Brawn. "But there is a limit; the monocoque, for example, is a basic thing that is already set."
Stuck, a German commentator and former F1 driver, thinks simply changing direction with the development of the W02 would not work for Mercedes.
"I doubt they can solve the problems with the current car," he said. "They took a risk with - by far - the car with the shortest wheelbase. This seems to maybe have not been the best idea," he said.
I doubt they can solve the problems with the current car
"It could well be that their season can only be saved with a new concept -- that is, a new chassis," added Stuck.
Meanwhile, Nico Rosberg has denied ridiculing the W02, with Cologne tabloid Express claiming he said: "It was planned that we start the (test) season with a cucumber, but not that we end up with a cucumber.