Toro Rosso Formula 1 boss Franz Tost is not expec🏅ting a final deci🔯sion to be taken on who will fill the team's second seat for the 2019 season until December, amid growing pressure upon the incumbent Brendon Hartley.

Toro Rosso confirmed last month that Daniil Kvyat would be returning for a t💃hird stint with🐈 the team next year, replacing the Red Bull-bound Pierre 🍬Gasly, with the second seat still bein🎐g vacant.

Two-time FIA WEC world champion Hartley has scored just four points so far this season, compared to Gasly's 28, leading to him facing pressure and speculation for much of the season, with rumours emerging as early as Canada that he could be🐼 replac🍌ed.

The New Zealander managed to record his best F1 finish to date 🅠last weekend in Austin, finishing ninth, but Tost stressed he needed to see an improved level 𒐪of performance if Hartley were to retain his seat.

"He showed a good race in Austin. But nevertheless, if you look at the results, he has four points, Pierre has 28 poi𓆉nts," Tost said.

"That means he has to improv🌞e his performance💮 if he wants to stay in the team."

Asked by mahbx.com if there was a deadline to make a decision on the𒊎 second 2019 seat, Tost said: "First of all, you have to finish the season to get a clear pictur♊e.

"Then 🍒I assume in December, Red Bu🐷ll will decide the driver line-up of Toro Rosso."

Hartley has long stressed that he 🐠is not dwelling o𝓡n his future with Toro Rosso as he has a valid contract to race with the team in 2019, and said on Thursday in Mexico that his circumstances had not changed.

"Nothin𓆉g’s changed from what I’ve been telling you. My contract is still valid for next year, so nothing changed from one week ago," Hartley said.

"I still believe I’m doing a good job, and when given the eq𓃲ual opportunities, I’m competitive against my teammate which in the end is what you’re asked to do in F﷽ormula 1.

"I’m lookin🦄g forward to the next three races and hopefully having another couple of good results like I did in the last f🐲ew races."

Hartley's se🌊at is thought to be at greatest risk of being lost to Formula 2 racer Alexander Albon, who had signed to race with Nissan in Formula E for the 2018/19 season that starts in December.

Albon, who sits s🐻econd in the Formula 2 standings heading into the season finale in Abu Dhabi, was pulled out of Formula E pre-season testing in Valencia last week at the last m🦹inute due to an approach from Toro Rosso.

While Tost confirmed that Albon was "of course" still in the frame for the seat in 2019, he refused to be drawn on how talks with Nissan regarding his release were going, saying: "Negotiations are 𒁃confidential.𝔍"