Gasly could still miss US GP to race in Super Formula

Red Bull motorsport chief Helmut Marko says that a decision will be made after the conclusion of the Japanese GP weekend.

If Gasly has to race at Suzuka, Toro Rosso faces the challenge of finding a replacement.

Gasly has previously suggested that he would prefer to race in Austin, but Honda has made it clear to Red Bull that it wants him to complete his commitments in Japan, where he is challenging for the title.

Having won two races this year, he currently lies just half a point behind Toyota-powered championship leader Hiroaki Ishiura.

Honda is keen on beating its rival engine supplier to the prestigious domestic title, while a title win for Gasly would mean that the Super Formula champion would be using Honda F1 engines at Toro Rosso in 2018.

The Toro Rosso announcement was rushed out in conjunction with Renault's confirmation of Carlos Sainz's early arrival for Austin, and it seems that Red Bull may have underestimated Honda's desire for Gasly to race at Suzuka.

"He can't do both," Marko told Motorsport.com. "We will decide after this race."

Asked if Red Bull had a Plan B for Austin should Gasly race in Japan, he said: "Yes, but I can't tell you."

The prospect of a Toro Rosso seat being available for the US GP has sent the rumour mill into overdrive, with Honda-powered Indy 500 winners Takuma Sato and Alexander Rossi, as well as IndyCar champion Josef Newgarden, all mentioned in connection with high-profile guest appearances.

But, given the lack of preparation time, it would be more logical for Toro Rosso to take a driver with current F1 experience, with Jolyon Palmer, Paul di Resta and Antonio Giovinazzi having all raced this year.

Those with extensive testing mileage also include newly-crowned Formula 2 champion Charles Leclerc.