Michael Schumacher has not ruled out standing in for injured Ferrari driver Felipe Massa although a comeback is highly unlikely, the retired champion's spokeswoman said yesterday.

"In these circumstances he would want to consider it and not categorically say no," said Sabine Kehm.

The seven-times world champion's manager Willi Weber dismissed the possibility of the 40-year-old racing again, however.

"Michael will not sit in a car in Valencia. This is out of the question," Weber told Germany's SID news agency.

The next race is in Spain on August 23 but Massa could be out for much, if not all, of the rest of the season.

"What would we expect from Schumacher if he stepped into a Formula One car? To win. The expectations from both sides would be too high," said Weber.

He added that the German could possibly test cars in the future but that would be as far as he would go: "For anything else it is a clear 'No'."

Kehm said her impression was that Schumacher, who retired after his last race with Ferrari in 2006, had no desire to get back behind the wheel.

"He always felt relief at not being part of it anymore," she said. "I never felt a temptation on his side (to return)".

Schumacher, Formula One's most successful driver with 91 wins, is still a consultant to the Italian team with whom he won five titles and remains in good physical condition, working out regularly.

The German is however still recovering from a motorcycle accident in mid-February and his neck might not be up to the considerable stresses of a grand prix car.

Massa, last year's championship runner-up, fractured his skull in an accident during qualifying for the Hungarian Grand Prix on Saturday and remains in intensive care in a Budapest hospital.