McLaren tested a Mercedes-like nose during Friday practice at Mugello.
F1’s homologation deadline, which will severely limit car changes for 2021 amid the corona crisis, expires at the end of September.
"We wanted to use our experimental nose to check whether the wind tunnel data matches the reality on the track," team boss Andreas Seidl told Auto Motor und Sport.
"If everything works, the new nose could come back later in the season," he added.
Carlos Sainz, who ran the new nose, commented: "It was supposed to be on the car this year, but other parts from this body kit are not yet ready.
"Therefore, we are testing them one at a time."