Cosworth's F1 boss Mark Gallagher is leaving the engine maker.
He joined the Northampton marque when it returned to Formula One last year, having amassed experience with Jordan and Jaguar and also world rallying and the A1 series.
He remains the founder and partner of the GP3 team Status Grand Prix.
"Had dinner with him in Spa and not a murmur," said The Times correspondent Kevin Eason on Twitter on Thursday. "What does it say for Cosworth's future?"
Agreed the Telegraph's Tom Cary: "What does it (Gallagher's departure) mean for Cosworth?"