For the second race in succession, Pascal Wehrlein has chosen to remain on sidelines at Sauber, fueling speculation about his alleged physical fitness issue.

The German driver pulled out of the season-opening Australian GP, invoking a fitness level too weak to endure a full race distance. Wehrlein was adamant however that he would be in good shape for China.

But the Sauber driver has pulled out once again, leaving Ferrari reserve driver Antonio Giovinazzi to sub for him at Sauber as the Italian did in Melbourne.

Many believe that it's unlikely Wehrlein will return to the cockpit before the Russian GP at Sochi, thus missing Bahrain next week and bringing forth questions and comments about his difficulties.

Former British racing driver and TV presenter Tiff Needell is suspicious about Wehrlein's excuses.

"Wehrlein doesn't think he's fit enough?! Do you think Giovinazzi ever thought 'but I'm not fit enough'," he wrote on Twitter.

The Brit's feelings were echoed by Italy's daily La Gazzetta dello Sport which noted that Sauber's announcement was "a day after Wehrlein said he wanted to at least do Friday practice" in China.

Germany's Auto Bild said Wehrlein was in the Mercedes F1 simulator on Monday, while Bild, as well, does not know how to interpret the Wehrlein story.

"He has now trained for two weeks (since Australia) to be fit," correspondent Lennart Wermke said.

"He is supervised by Josef Leberer, once the physio to the great Ayrton Senna. But according to Sauber, the ambitious Wehrlein is voluntarily not racing?

"Will Wehrlein be fit enough for Bahrain? Or is there something more to this?" Wermke asked.

Strangely, neither Sauber nor Wehrlein have provided any insight from a doctor or the medical profession.

It seems indeed hard to believe that a perfectly healthy 22-year-old professional racing driver would lack the ability to race, even if the new-spec cars are physically more demanding.

After all, substitute Giovinazzi hardly had more mileage than Wehrlein in Sauber's new C36 before he unexpectedly climbed aboard in Australia.

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