Proud Nico Rosberg on joining Ferrari and Formula One comeback

Reigning Formula One world champion Nico Rosberg has dismissed suggestions he could come out of retirement and race for Ferrari. The German won his maiden drivers' championship with Mercedes last season but dramatically called time on his motorsport career less than a week after that success.

The 31-year-old cited the demands of the sport as a key reason behind his decision, following a campaign when his duel with teammate Lewis Hamilton became deeply personal. Rosberg remains an ambassador with the Silver Arrows, appearing at a handful of races on the calendar, but has no plans to race in 2017 or beyond.

Speaking at the Canadian Grand Prix, Mercedes co-owner Toto Wolff suggested Rosberg could return to F1, potentially signing for Ferrari whose lead driver Sebastian Vettel has a 12-point lead in this year's championship after seven races of the season.

"I think when he took the decision to retire it was because it was just too much," said Wolff.

"It was a very stressful year against probably the best driver in F1 and he felt, at that stage, exhausted. That is how he appeared to me. But he is 31 years old.

"If he is unlucky, he has another 70 years to go in his life! I will give you one [quote]: I wouldn't be surprised if he changes his mind in a year and reappears in a Ferrari! Or somewhere else."

But Rosberg has responded to the speculative remarks in astonishment and insists his days in F1 are firmly over. "No, I really have finished my career," he told Germany's Sport Bild. "I am happy and proud of the results and the successes I have had. It fulfils me a lot. But it's now in the past, and I'm going to do new things."

Fernando Alonso became the latest F1 driver to explore a career in endurance racing when he competed in the Indy 500 for the McLaren-Honda-Andretti. The Spaniard impressed in qualifying and then on race day but was forced to retired with 20 laps to go with engine failure – ironically an issue that has beset him in F1 this term.

Though happy to link Rosberg with a return to F1, Wolff does not believe he will be convinced to take on the 200-lap race. "I think that doing the Indy 500 is very challenging for a racing driver," he added. "I loved it because of Fernando, until he retired, but I don't think Nico calculating the risk and reward would go on to an oval with an Indycar."