Niki Lauda will miss both the forthcoming Barcelona tests and the first race of the season in Australia.
That is the claim of the F1 legend's Austrian countryman and paddock friend Dr Helmut Marko.
Lauda, 69, has had a long and complex recovery from a 2018 lung transplant, but had hoped to be well enough to return to the pitlane in 2019.
"The six month stay in hospital was difficult for Niki," Marko, a top Red Bull official, told the German broadcaster RTL.
"Niki still has a long way to go. He needs a lot of patience," he said of the 69-year-old Mercedes team chairman.
"A comeback at the test days in Barcelona is not possible, and a long trip to Australia for the start of the new season is too early for him," Marko added.
"Niki will support his team by telephone."
