Daniil Kvyat may not race for Toro Rosso beyond this weekend's United States Grand Prix despite Carlos Sainz's early switch to Renault, according to reports.

An out-of-form Kvyat was dropped ahead of the Malaysia GP so the team could evaluate young driver Pierre Gasly.

Yet with Carlos Sainz making an early move to rivals Renault, Kvyat will return to action in Austin.

Pierre Gasly's Super Formula commitments mean the Russian will race alongside experienced sports car racer Brendon Hartley.

Kvyat is then expected to see out the season alongside Gasly, but rumour has it that could all depend on his performance relative to Hartley at the Circuit of the Americas.

The 23-year-old has scored only four points in a wretched 2017 campaign, testing the patience of Toro Rosso.

If Hartley turns in an impressive display, he could yet be handed another outing at the next race in Mexico.

The decision will rest with Red Bull's notoriously ruthless motorsport consultant Dr. Helmut Marko.

Should Kvyat be ousted for a second time, it would surely see him leave the Red Bull set-up once and for all.