Porsche is considering an entry into Formula 1 for 2021 contends former McLaren and Ferrari driver, and DTM boss, Gerhard Berger.
The German manufacturer pulled the plug on its WEC programme at the end of last year to devote its resources to Formula E which it will enter in 2019.
However, it was revealed late November that a 30-strong engineering team devoted to developing hybrid technology has remained active in Weissach, perhaps building the foundation for a future F1 power unit.
"Porsche is thinking about a Formula 1 entry for 2021," Berger told Auto Bild.
"They are just waiting for the new engine regulations, which should be published in May, and then will decide," he added.
F1 owner Liberty Media's sporting boss Ross Brawn said the sport would welcome Porsche to the grid.
"We want to have big names like Porsche in Formula 1 and are creating the environment for it," he said.
Porsche CEO Oliver Blume is mum however on the subject of the Stuttgart firm eventually returning to the fray of Grand Prix racing.
"I won't comment on Formula 1," said Blume last year.
"For now, we're concentrating on Formula E. At Porsche, we've always been well advised to focus on one thing, so as not to overstrain the company."