Rossi has had several test drives for Ferrari

The five-time MotoGP champion's Yamaha contract runs out after this season and he has been tipped to join Ferrari.

"For both teams, I need to decide what I am doing in a short time, I think two or three months," he told the BBC.

"Going in F1 will be hard on my private life. Already for me it's over the limit, so to think worse is difficult."

Rossi sets pace at opener

With several old rivals like Sete Gibernau and Max Biaggi having changed teams or even left MotoGP, Rossi starts the season as favourite to retain his title.

But he said there are new young guns ready to take up the challenge, one of whom - 250cc world champion Dani Pedrosa - is new to the class.

"My historic rivals have changed," he said.

"Biaggi is finished and Gibernau has moved from Honda to Ducati so may be less fast, but Dani Pedrosa and Nicky Hayden have arrived, and they want to beat me.

"I think Pedrosa will be very strong in the future. Maybe this year at the start he will have some problems, but he rides very well, so I think he and Melandri are my fastest rivals."