The 2020 Formula One grid continues to take shape.
Here are the major pieces of the puzzle still to fall into place for next year, with one of the grid's most coveted seats still up for grabs ...
Red Bull
Max Verstappen, To Be Confirmed
Toro Rosso
TBC, TBC
Red Bull is in the middle of an experiment that will define the 2020 lineup of both its Formula One teams. During the summer break, it confirmed that out-of-form Pierre Gasly was being sent back to Toro Rosso to rediscover his confidence, with impressive rookie Alexander Albon going in the other direction. The reasoning was simple: to give the team a like-for-like comparison between Gasly and Albon in order to make a decision on who should partner Verstappen at Red Bull in 2020.
Albon's first two race weekends (Belgium and Italy) were impressive but are hard to judge fairly. Results between now and the end of the season could help shape the team's decision.
Red Bull has dismissed suggestions it would look outside of its driver programme, so despite the occasional report linking Fernando Alonso or Nico Hulkenberg to the vacant seat alongside Verstappen, it seems highly unlikely the Austrian company will deviate from its tried-and-tested policy towards driver selection.
That leaves one other name in the mix: Daniil Kvyat. The Russian returned to the F1 grid this year with Toro Rosso and claimed a memorable podium finish at the German Grand Prix. Kvyat's career history includes a short spell at Red Bull that famously ended in a demotion (Verstappen went in the other direction on that occasion).
However, Kvyat has enjoyed a career resurgence of late and is a known quantity. Given his background with the team, he might not look like an obvious candidate, but he provides Red Bull a reliable alternative if bosses feel neither Albon nor Gasly is ready to partner Verstappen in what should be a more competitive car in 2020.
It is still unclear whether Mexican driver Pato O'Ward, a new addition to the driver programme, will have enough superlicence points to be considered for a Toro Rosso seat next year. If O'Ward cannot step up, it is likely the two drivers who are overlooked for Red Bull's main seat will end up back at the junior outfit based out of Faenza in Italy.
Alfa Romeo
Kimi Raikkonen, TBC
The 2020 season will represent the second year of Raikkonen's two-year contract with Alfa Romeo, and there is no reason to believe either side will bail out of that agreement. However, teammate Antonio Giovinazzi's future at the team is far less certain.
Alfa Romeo is ultimately owned by the same parent company as Ferrari, and its sponsorship deal of Sauber means Ferrari has a say over who occupies the second seat alongside Raikkonen. Mick Schumacher, the son of seven-time champion Michael, is the most high-profile name in the Ferrari Driver Academy and, after testing for both Ferrari and Alfa Romeo in Bahrain, appears to be destined for F1.
But Schumacher's debut year in F2 has been underwhelming so far and it took until the sprint race in Hungary for him to secure his first win -- largely thanks to a reverse grid pole position. In Formula 3 last year, he kicked on in the second half of the season to secure the championship, but he faces a much bigger challenge in F2 and would likely benefit from a second year in F1's feeder series to hone his skills.
That could result in a stay of execution for Giovinazzi, who claimed a well-timed return to the top 10 at his home race at Monza. Hulkenberg remains an interesting option, and another outside bet for the seat could be Pascal Wehrlein, who last raced in F1 for Sauber in 2017, as he is looking for a way back into the sport and is currently a Ferrari simulator driver.
Williams
George Russell, TBC
Ahead of the Singapore Grand Prix, Robert Kubica confirmed he won't stay with Williams beyond 2019, drawing a curtain on his remarkable but ultimately underwhelming comeback season. That leaves the Grove team with a vacant seat. Canada's Nicholas Latifi is on course to secure the necessary superlicence points to move up to F1 next year and has the potential to bring a weighty financial package with him, making him the obvious candidate. He is currently second in the F2 championship and, in his role as Williams' test and development driver, has contested several Friday practice sessions for the team so far this year.
In August, Mercedes confirmed it will honour the second year of its junior driver Russell's contract at Williams, meaning the reigning F2 champion will stay put in 2020. Mercedes boss Toto Wolff wants him to learn his trade at the team, even if it means driving at the back of the grid for another couple of seasons, and, at 21 years of age, Russell has time on his side.
Russell's long-term prospects look to have improved significantly with Mercedes letting Esteban Ocon move to Renault, a ringing endorsement of the English driver's ability to step up to its main team in the near future.
The following spots on the grid have been confirmed.
Mercedes
Lewis Hamilton, Valtteri Bottas
If it ain't broke, don't fix it. Mercedes boss Wolff used the summer break to decide whether to retain Bottas for another year or promote the team's former junior driver Ocon. He chose the former, letting Ocon move to Renault in the process, safe in the knowledge that Russell should be a viable candidate for a step up after another season with Williams in 2020. Bottas' deal is for one season, meaning he will once again be driving to prove he deserves another extension with the modern era's most dominant team.
Ferrari
Sebastian Vettel, Charles Leclerc
Despite murmurings that Vettel could be on his way out of Ferrari at the end of the year, the four-time world champion still has another year on his contract and shows no signs of wanting to cut his career short. Leclerc, or "the little prince who is already a King", as the Italian media dubbed him after his victory at Monza, will remain in a team that is looking increasingly like his own.
Renault
Daniel Ricciardo, Esteban Ocon
Renault signed Ricciardo to a lucrative two-year deal when it poached the Australian driver from Red Bull, so he will remain in 2020. Intriguingly, he will be a free agent at the end of next year at a time when some interesting options might be on the table.
Joining Ricciardo will be highly rated Ocon, who spent a year without a race seat despite an impressive couple of seasons with Force India. Ocon's arrival is manna from heaven for Renault, giving it a French driver to lead the team -- his deal will see him stay with the team into 2021, the year Renault hopes to leap back to the front of the grid under the new rules. Ocon's break was bad news for Hulkenberg, who is still without an F1 race seat for next year.
Haas
Kevin Magnussen, Romain Grosjean
Ahead of the Singapore Grand Prix, Haas confirmed the somewhat surprising decision to retain its current line-up. Magnussen's current deal runs until the end of 2020, but there were questions whether Grosjean, who has had patches of really shaky form over the past two seasons, would be replaced for next season. The presence of Hulkenberg on the driver market seemed to give Haas a ready-made and reliable replacement, but it decided to stick with the man who joined ahead of the American team's debut season on the grid in 2016.
McLaren
Carlos Sainz, Lando Norris
Ahead of the British Grand Prix, McLaren confirmed it would continue with the same driver line-up for 2020. It came as little surprise given the upward trajectory of the team and the positive relationship between the two drivers. The only other thing it confirmed, although it wasn't really a surprise, was that Alonso would not be returning with McLaren next year.
Racing Point
Lance Stroll, Sergio Perez
Perez will remain with Racing Point until the 2022 season, after a three-year contract extension was confirmed during the Belgian Grand Prix weekend. Perez joined the outfit under its former guise, Force India, in 2014 and helped save the team from administration last summer. Lance Stroll, son of the team's billionaire owner Lawrence, will remain at the team.