Injury concerns have stalled plans for seven-time world champion Michael Schumacher's return to Formual One for Ferrari
The 40-year-old was due to replace the injured Felipe Massa, but a neck injury from a motorcycle accident earlier this year has been causing him pain during testing.
Ferrari has given the seat to test driver Luca Badoer.
"I really tried everything to make that temporary comeback possible, however much to my regret it didn't work out," Schumacher wrote on his website.
"Unfortunately we did not manage to get a grip on the pain in the neck which occurred after the private F1-day in Mugello (last week), even if medically or therapeutically we tried everything possible."
Schumacher, who retired in 2006, had been expected to return for the European Grand Prix on 23 August while Massa continued his rehabilitation from a fractured skull.
"The consequences of the injuries caused by the bike accident in February, fractures in the area of head and neck, unfortunately have turned out to be still too severe," Schumacher added.
"That is why my neck cannot stand the extreme stresses caused by Formula One yet. These are the clear results of the examinations we did ... over the past two weeks and the final examination yesterday afternoon."
Mercedes, who own 40 percent of the McLaren team and also provide engines to Brawn GP and Force India, said Schumacher's withdrawal was bad news.
"This is a bitter disappointment for everyone who was looking forward to Michael's comeback," Mercedes motorsport vice-president Norbert Haug told reporters.
Italian driver Luca Badoer started 49 races for Scuderia Italia, Minardi and Forti without scoring a point between 1993-99. His last competitive drive was at the Japanese Grand Prix almost a decade ago.