Dr Helmut Marko has essentially confirmed reports that negotiations between Red Bull and Porsche about a works deal for 2026 and beyond have stalled.
When announcing that fellow VW brand Audi will be on the grid in 2026, CEO Markus Duesmann indicated last week in Belgium that Porsche is definitely coming to Formula 1.
Red Bull's top Austrian official Marko, however, told Auto Bild: "He's premature.
"The talks are not over yet.
"But Formula 1 is booming in such a way that it is a logical step for every self-respecting car manufacturer."
The clock is now ticking for Porsche, as any potential new engine manufacturer must - like Audi - officially enter the championship by October 15.
Red Bull team boss Christian Horner, however, insists that there is still time.
"It's 10 past midnight and Cinderella's already buggered off," he laughed. "So it's tight, but that's Formula 1 and that's some of the creativeness and drive that happens within the teams.
"It's going to be exciting to see more power unit manufacturers on the grid for 2026," Horner added.
