Michael Schumacher is saddened by Valentino Rossi's decision to spurn Formula One and stay on in MotoGP.

Five-times MotoGP champion Rossi disclosed he would not pursue his Formula One ambitions despite extensive testing with Ferrari.

The Italian had hoped to become just the second man, after Englishman John Surtees, to win world titles on two and four wheels but that new career will have to wait beyond next season.

Schumacher, who has seen at first hand Rossi's progress behind the wheel of a Ferrari, revealed the five-time bike champion had the ability to make it in Formula One.

He said: "In a way we are sad not to see him here but on the other side it is understandable because he knows what he has in his world.

"It is maybe a little bit more difficult to know the world of Formula One and how you would adapt to different circumstances.

"I think he has a lot of talent in terms of driving but it is not only in terms of driving. It is sad but that's the way it is."

Ferrari team boss Jean Todt wished Rossi well in his extended MotoGP career, despite today's news limiting his driver options for next season.

Rossi was on the list of potential drivers to replace Schumacher, should the seven-time champion retire at the end of this season.

Kimi Raikkonen is widely expected to switch from McLaren to Ferrari and, realistically, Todt now only has Felipe Massa as an option to partner him in 2007 if Schumacher hangs up his helmet.

The Frenchman was full of praise for Rossi though, adding: "It has been a pleasure giving him the chance in Formula One.

"Valentino has quickly shown he has great professionalism which makes him an exceptional champion.

"Everyone at Ferrari has been struck by his ability to adapt to Formula One. Now we will follow with great affection his challenge in MotoGP and hope he achieves his goals."

Not everyone on the Monaco paddock ahead of this weekend's grand prix was disappointed to hear Rossi will not be joining the circus next year.

Fernando Alonso quickly tired of the speculation and was even challenged to a duel by Rossi, who proposed a shoot-out in a Formula One car, a World Rally car and on a MotoGP bike to determine the champion of champions.

When told of Rossi's decision, Alonso said: "Good, so we don't talk any more about him. After four months maybe this is the last question about Rossi."

Jenson Button was less hostile to the idea but still claims Rossi's decision to stay on two-wheels is in the best interests of Formula One and MotoGP.

The Honda driver believes Rossi's mystique, built up over years of MotoGP domination, would quickly evaporate if he could not reproduce that dominance in Formula One.

He said: "In testing he went reasonably well but he had a lot of miles in the car. If another driver got in the car and didn't go quick on day one or day two no-one would be interested. It's because of his status.

"I think he's done the right thing staying at what he's good at. If he finished tenth or 12th in every race what does that do to his reputation? I don't think it's good for either sport."