Michael Schumacher is thinking about pulling out of Formula 1 at the end of this season, according to BBC Sport pundit Eddie Jordan.
The German, 41, ended three years in retirement when he signed last winter a three-year deal to drive for Mercedes.
"I've a hunch something fundamental has changed. I believe he is disillusioned and thinking of quitting," said Jordan.
Jordan said: "There are too many indications that now give me the feeling he is reconsidering his commitment to his three-year contract.
"There is far too much movement in the Mercedes motorhome involving managers from drivers from other teams.
"I have heard rumours that (team principal) Ross Brawn's continuity with the team is in doubt, which would be a huge blow.
"It's also rumoured that as a result of the lack of performance of the Mercedes car, expectations for next year within the team are not as high as they were at first.
"The Barrichello incident ...