Red Bull has not decided if Pierre Gasly will be released to fight for the Japanese Super Formula title next month.
As the French rookie makes his debut at Sepang, it was rumoured axed Daniil Kvyat could return to his Toro Rosso for Austin.
That’s because Gasly has contested the full Super Formula season, and could win the title if he is able to return to Japan to do the Suzuka finale.
Suzuka clashes with the US grand prix, but Toro Rosso boss Franz Tost admitted it is not decided if Gasly will be allowed to race in Japan.
"In a normal situation, Pierre would be in the car for the remaining (F1) races," he told Speed Week.
"Austin clashes with the final of the Super Formula, so we will have to weigh everything and then make a decision," Tost added.
Earlier, team owner Red Bull said Gasly is replacing Kvyat so that the French youngster can be analysed for a potential full race seat in 2018.
Tost said the Faenza based team is happy with Gasly so far.
"I assume that we will get together at the end of October to decide about our team (for 2018)," he said.