Alain Prost believes there is only a "50-50" chance Lewis Hamilton will return to F1 this season.
Thirty days since Hamilton dramatically missed out on a record-breaking eighth title following a controversial conclusion to the season-ending Abu Dhabi Grand Prix, the Briton has so far kept his counsel.
With Mercedes team principal Toto Wolff declaring Hamilton disillusioned in the days that followed the race, the continued silence is fuelling rumours he may yet decide to call it quits.
Prost, a four-time champion and non-executive director of Alpine, can understand the mindset of Hamilton given the way the last few laps unfolded in Abu Dhabi where it appeared certain he would be champion again, only to be cruelly denied.
Speaking in Le Journal du Dimanche, Prost said: "It's difficult to put yourself in his place. He surely has as many reasons to stop as to continue. It's 50-50.
"He took a hell of a blow to the head, but it would be really sad if he wasn't here this season."
Prost is hopeful the new rules for the coming season, with the cars sporting different aerodynamic architecture in a bid to promote closer racing, will be enough of a lure to Hamilton, who has two years remaining on his Mercedes contract.
"I want to remain optimistic because there is this eighth title to go for and this new technical regulation, with maybe three teams in the lead and four or five drivers vying for the title," added Prost.
"It's a challenge Hamilton might want to take on. "