Following Carlos Sainz's move to Renault with immediate effect after the Japanese Grand Prix, Toro Rosso will bring back Daniil Kvyat to race alongside Pierre Gasly in Austin.
The French driver was in the running for the Japanese Super Formula title for the series' finale clashes with the US GP at Austin.
Toro Rosso has now decided to keep the 21-year-old on board for the remainder of the season.
"I would like to thank Carlos for all his efforts over almost three Formula 1 seasons," said team boss Franz Tost.
"He always did his very best, demonstrating an excellent attitude and commitment to his work, which helped him and us to get some great results during that time.
"Therefore, on behalf of everyone at Toro Rosso, I wish him all the very best with his new team. We look forward to beating him on track!"
Speculation around Sainz's future had been mounting for months and indeed many were expecting him to move to Renault even earlier.
"First of all I would like to thank Toro Rosso and Red Bull for allowing me the possibility of finishing this season with Renault Sport Racing," said the Spaniard.
"More specifically, I really want to thank all my engineers and mechanics for their support and tremendous work throughout these years.
"Toro Rosso is made up of a fantastic group of people and I wish them only the best for the future.
"On my side, I will definitely do my very best in tomorrow’s race… this would be the best possible send-off!
"Additionally, competing in these last four races with Renault gives me a good opportunity to get to know the team and the car earlier than expected. I am looking forward to start working with them."