Wehrlein was involved a big accident during the Race of Champions last month, when he lost control of his car and made contact into the car driven by Felipe Massa.

Wehrlein's car flipped over Massa's left-front wheel and ended up hitting the barriers.

The German driver appeared to be unscathed and later reported to be okay.

German media reported on Monday, however, that Wehrlein had suffered a neck injury in the accident, claiming he could be forced to miss some of the testing that kicks off on February 27.

On Monday, Sauber labelled the reports as "pure speculation", but did reveal Wehrlein was still undergoing medical tests.

"Current rumours about Pascal Wehrlein in the media: The medical examinations are still ongoing," said Sauber.

"Therefore, the reports are pure speculations. We will provide information in due time."

Wehrlein will race with Sauber this year alongside Marcus Ericsson after having made his grand prix debut with Manor last year.