Pascal Wehrlein is still recovering from a scary rollover crash that occurred during the race of champions event in Miami.
Last month, the Sauber driver was sidelined by doctors at the event after rolling a bizarre three-wheeler into a barrier following contact with Felipe Massa.
"It's no more than mild discomfort but my real priority for the coming year is my Formula 1 season," German Wehrlein, 22, said at the time.
Now, Germany's Auto Motor und Sport reports that Wehrlein "obviously injured himself more heavily" than that and could miss the start of F1 testing later this month, adding that "Wehrlein suffered a neck injury that requires a longer healing phase".
It is alarming news for Wehrlein, given the fact that drivers are currently increasing the strength of their necks for the much faster cars of 2017.
The report added that new Ferrari reserve Antonio Giovinazzi could be called up as a substitute, but Sauber said on Twitter that the reports "are pure speculation".