When MotoGP testing kicks off at Sepang in just over three weeks' time, it'll mark the first preparations for a motorcycle grand prix season without Valentino Rossi since 1995.

Exactly what impact the retirement of the most famous motorcycle racer in history will have on MotoGP is yet to be seen.

Perhaps Rossi's millions of followers will continue to tune in for each race weekend and find new riders to support. Or perhaps they'll lose interest and find something else to do. No-one really knows.

Either way, it's a pivotal moment for the sport, which has grown exponentially during the Rossi era but must now try and continue the momentum without him.

Many, including Rossi's long-time boss Lin Jarvis of Yamaha, take comfort from the example of Formula 1, which - since Rossi's 1996 debut - has lost several all-time greats but eventually seen new heroes emerge.

"Obviously we spent 16 years with Valentino and we've seen the value of him to the sport, we've all seen that, but also to our brand," Jarvis said. "He's been really a cherished icon and asset to our brand and we hope to take that forward into the future and keep our relationship with Valentino.

"As far as the sport goes, I think we've all benefitted from the popularity that he's brought to this sport over all of the years. But all sports move on and you've seen it before whether it be in skiing, tennis or Formula 1.

"After the sad passing of Ayrton Senna, Formula 1 continued with Schumacher. You have legends but the sport at the end of the day always moves on and there's always young people coming through.

"In Formula 1 now you have the existing icon (Lewis Hamilton) and you have the next generation coming up as well. There are some great young drivers coming on in Formula 1. We've been through the Senna years, then the Schumacher years, Sebastian Vettel and Lewis Hamilton domination.

"But now look at the young guns coming up. They are fun, young and fast. We have this crazy orange Verstappen movement at the moment and that will probably carry that sport forward.

"I think that will probably happen in MotoGP as well, we have tremendous racing, incredibly exciting in all three classes and I think the sport will continue to grow in the future."

Ducati sporting director Paolo Ciabatti also has faith that action-packed racing can keep Valentino Rossi fans from drifting away, but warned the sport will have to work harder to attract the same level of attention.

"I agree with Lin, but I think Valentino is not replaceable in the sense that he was an iconic rider. I can only think of Giacomo Agostini in his era being so famous also outside of the racing fanbase," Ciabatti explained.

"So for sure it will not be easy to attract the same kind of attention from spectators that were liking the sport because they were willing to see what Valentino was doing, [especially] when Valentino was winning.

"On the other side I think the competition on the track is so exciting. We have many young riders that are super-fast, every race is so much fun to watch.

"So hopefully people that came to see MotoGP because they wanted to support Valentino will also realise that it's a nice show, either at the track or on TV. It's a very good format, 45 minutes of action, no pit stops or strategy, and it’s very enjoyable.

"So we hope that with the new up-and-coming riders we can keep a similar level of support from the fans. But Valentino will be missed."

Repsol Honda's Alberto Puig believes the quality of the racing is the most important thing and that 'life goes on'.

"In the history of this sport there have been many great riders. Valentino is one of them but there have been a lot of super riders and life goes on. Generations keep coming through," he said.

"I think all the people that were important in racing will always be remembered, but the time we are living is now.

"I don't think racing is going to be affected if this guy or another guy is here or not. The important thing is the racing itself. The way this championship is organised now, it's so exciting that people will follow.

"But of course Valentino Rossi will be one of guys in the history of motorsport that will be remembered as one of the best. This is for sure."

Hopes will be high that MotoGP's new Amazon series can reach new fans in the same way as Drive to Survive boosted F1, but compounding MotoGP's apprehension following the departure of Rossi is the impact of ongoing Covid regulations on trackside attendance and uncertainly over the race fitness of Puig's rider Marc Marquez, the sport's second-biggest star.

Using Instagram as a rough guide of 'fame' or 'influence', Rossi currently has 12.7 million followers, literally bigger than MotoGP itself on 11.9 million (a similar situation occurs in F1 with Lewis Hamilton). Marquez has 5.6 million, Quartararo 1.7 million, Dovizioso 1.4 million, Vinales 1.3 million, Bagnaia 725,000, Miller 637,000 and Mir 497,000 etc.

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Just one away from Rossi's nine world championships, the stage is set for MotoGP fans to witness some epic battles between Marquez – who at 29 will be the seasoned veteran - and the new generation of racing heroes such as recent world champions Joan Mir and Fabio Quartararo, plus Ducati's Francesco Bagnaia.

A similar situation occurred in Rossi's career when, after his most dominant seasons, he then went 'bar-to-'bar with the next generation of Casey Stoner, Dani PedrosaJorge Lorenzo and finally Marquez, producing some of the sport's most memorable battles and controversial moments.

In other words, Marquez vs the rising stars could be exactly the type of dramatic title fight the likes of Jarvis, Ciabatti and Puig believe can keep MotoGP fans glued to their seats on a Sunday afternoon.

But it's already been put on hold for the past two seasons by injuries for Marquez, who is currently sidelined by double vision problems, casting doubt on his fitness for the start of 2022...