Wehrlein told the Swiss team after Friday's practice session he had concerns over his fitness, having suffered a back injury in January's Race of Champions event.

The German driver had to miss the first test at Barcelona because of the injury and admitted he only realised after driving on Friday that the training setback left him short of full fitness.

Kaltenborn believes Wehrlein's decision to stand down should be praised, not criticised.

"He just needs time," Kaltenborn told Motorsport.com. "I think it is really awful how people think they have any sort of competence to say anything about him.

"They just have their weird views from wherever they come and have no authority at all to judge over anyone. I think it is rather appalling how people think they can judge this and they should look at themselves first.

"It takes a lot for someone so ambitious to openly admit and say, 'Guys, in these circumstances, I cannot cover the entire race distance'.

"So one should rather appreciate that kind of openness and honesty, which is not easy to maintain with the kind of pressure these guys have."

Antonio Giovinazzi stood in for Wehrlein, who is due to return for the next race in China on April 9.

Kaltenborn said Wehrlein would not seek a specialist between now and the Shanghai race because his fitness would improve sufficiently in the interim for the team not to be concerned.

No doubts after second test

Wehrlein completed four half-days at Barcelona in the second week of pre-season testing, but was limited to short runs as a precaution.

Kaltenborn said it was "very surprising" he had even been cleared to take part in testing, which made everybody believe he had returned to full fitness.

But asked if the team had any indication of a problem after the second test, she replied: "Not at all. I would never have done this otherwise.

"You cannot have indication for this because then you know something really isn't right. We started building him up because that was the right thing to do.

"It was the right step not to put someone in the car all day, so we split it – other teams do it too, without having this situation.

"We came here with clear intention that he is going to drive all weekend."