Summer blow fuelled Schumacher return

The seven-time champion had been pencilled in as Felipe Massa's temporary replacement from the European Grand Prix, but he had to call off his F1 return at the time because of a neck injury.

However, he has revealed that the feelings he experienced at the time caused him to rethink his future plans - and set about a sequence of events that has resulted in him returning to F1 with Mercedes GP.

"Until recently, I was absolutely sure that I had ended my career as a race driver at Ferrari," Schumacher wrote on his official website.

"But sometimes things change suddenly and unexpectedly. All of a sudden, the framework conditions aren't the same anymore. At that point, you have to reconsider the decisions you've made. And, to tell the truth, the failed comeback attempt last summer gave me reason to reconsider my situation.

"I was surprised myself how fast and how strong I committed myself to this topic again. Apparently, my batteries recharged completely during the last three years. And when - thanks to Ross [Brawn] - the opportunity arose to drive for Mercedes GP, I realized that my old motivation was back, full of fresh energy and great force."

He added: "Physically, I feel absolutely fit. I already realised in [the] summer how fast I achieved my former performance values by exercising specifically. And ever since, I kept on exercising. My neck is absolutely free of complaints. I can now do the same neck work-out as I did when I was still racing.

"This wasn't possible in summer because back then only five months had passed since my accident and so my neck wasn't cured completely. In the meantime this isn't a problem any more."

Schumacher said that Ross Brawn initially approached him at the season-closing Abu Dhabi Grand Prix, but it was not until a phone call last month that the situation really developed.

"Of course it plays a major role that I again can work together with Ross at Mercedes GP. Above all, however, my old hunger for racing is back.

"In Abu Dhabi, when Ross asked me if I could imagine returning to F1, I felt that I wasn't ready for it. But only two weeks later, when he called me once again, I realised that my old passion was returning. Suddenly I was on fire again. For me, the imagination to be back in a F1 car and to compete for the world championships is exciting and extremely inspiring."

And Schumacher has expressed some sadness at having to leave Ferrari for his latest challenge.

"Ferrari and I have been working together for 14 years and I've experienced a lot of great moments with the team during this time," he said.

"Most of my life as a Formula 1 driver is 'red' and so there is strong solidarity and loyalty to these guys who have accompanied me and have always built great cars for me. This solidarity will remain, even though our teams will be competitors on the race track - because I'm certain that Ferrari will regain its former strength since the crew is really strong and committed."