Seven-time Formula 1 champion Michael Schumacher has abandoned his comeback with Ferrari because of a neck injury.
The 40-year-old, who retired at the end of 2006, was set to deputise for the injured Felipe Massa at the European Grand Prix in Valencia on 23 August.
"Unfortunately we did not manage to get a grip on the pain in the neck which occurred after the private F1-day in Mugello," Schumacher told his website.
Veteran Ferrari test driver Luca Badoer will now stand in for Massa.
Schumacher aggravated a neck injury he originally suffered in a bike accident in February whilst trying out a 2007 F1 car as he set about making his comeback.
"That is why my neck cannot stand the extreme stresses caused by F1 yet. These are the clear results of the examinations we did on the course of the past two weeks and the final examination on Monday afternoon.
"As there were no improvements after the day in Mugello, I decided at short notice on Sunday to do that thorough examination on Monday."
Schumacher contacted Ferrari president Luca di Montezemolo and team boss Stefano Domenicali on Monday evening to tell them he had lost his fitness battle.
"I'm very sorry about the problem that will stop Michael returning to racing," Montezemolo said.
"His return would surely have done Formula 1 good and I'm certain we'd have seen him fighting for victory again.