Mercedes' W07 is due to appear with a new specification nose at some stage during the final two days of testing in Barcelona.
Following a scheduled introduction of various "unusual parts", as labeled by Mercedes boss Toto Wolff, the first of which was unveiled on Tuesday in the form of a novel bargeboard design, the German team is set to add a second upgrade when it trials a new nose design, according to Mercedes executive director Paddy Lowe.
"We will have a new nose," he confirmed. "That’s typical of the sport at this stage; we’re bringing lots of new parts to the car on a daily basis - all the way up to the first races."
At present, Mercedes is unlikely to run the nose on Wednesday as it focuses on set-up work, but has not ruled out new parts being tested.
Rosberg emerged for his first run with the launch-spec nose on the car, carrying a major aero rake as part of early data gathering. The German will drive in the morning session before handing over to team-mate Lewis Hamilton in a change of plans from the original schedule which had Hamilton in the car all day.
Mercedes has completed comfortably the most mileage of any team so far during the first test, with Rosberg adding 172 laps yesterday to Hamilton's tally of 156 on Monday.
UPDATE: Mercedes confirmed to F1i on Wednesday afternoon it does not plan on running the new nose until Thursday as it wants to evaluate other new parts with a stable baseline.
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