Michael Schumacher has abandoned his Formula One 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.

Schumacher suffered the neck injury in a bike accident in February.

"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," he added.

"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."

Seven-time world champion Schumacher won five championships with Ferrari and had been working as a consultant for the Italian team before his decision to come out of retirement to stand in for Massa.

The German, who claimed his other two drivers' crowns with Benetton, has entered 250 grands prix, winning a record 91 of them.

His return was being eagerly anticipated but, despite trying everything 'medically or therapeutically' possible, he has had to admit defeat.

"I am disappointed to the core," said the German. "I am awfully sorry for the guys of Ferrari and for all the fans which crossed fingers for me.

"I can only repeat that I tried everything that was within my power. All I can do now is to keep my fingers crossed for the whole team for the coming races."

MICHAEL SCHUMACHER may have been prevented from testing a current Ferrari Formula One car in his build-up to the European Grand Prix.

The seven-times world champion has not driven competitively since the season-ending Brazilian Grand Prix in October 2006.