ESPN looks at the remaining question-marks on the 2017 grid and the top candidates for each seat.
Felipe Massa's retirement announcement in Monza confirmed what was already widely expected in the paddock, that there will be a vacancy at Williams next year. But the narrative changed that very same weekend when Jenson Button announced he will be in a reserve role at McLaren next year, ending the chances of returning to the team he started his F1 career with in 2000.
Interestingly, Williams is yet to confirm either of its drivers for next season. Despite being held in high regard by the team, Valtteri Bottas is still unclear where he will be next year. The Finn was strongly linked with Renault for 2017 but it is looking increasingly likely he will stay for another season at Williams.
Reserve driver Alex Lynn's poor GP2 season has hampered his chances of filling the other seat, while Sauber's Felipe Nasr looked to be an outside bet with his previous links to the Williams team. But the favourite to land a seat is Formula 3 leader Lance Stroll. The well-funded Canadian teenager brings the golden combination of talent and money to the team, and has been using his finances to privately test a 2014-spec Williams on current circuits in a bid to prepare himself for a future seat.
Force India's line-up should have been straightforward: Vijay Mallya confirmed another year of Nico Hulkenberg and Sergio Perez at the British Grand Prix. That was immediately contradicted by Sergio Perez, who insisted he would look elsewhere for a drive if his sponsors could not reach a favourable agreement with Force India.
Renault might well be a good bet for future and you can understand Perez keeping his options open on that front, but Force India is a team on the up and continues to show what it can do on limited resources -- staying put will also keep him in the frame for a switch to Ferrari in 2018. Another year of Perez and Force India is expected to be confirmed imminently.
Neither Kevin Magnussen or Jolyon Palmer are sure if they will be retained next season and it is looking increasingly unlikely the latter has a future at the team. Esteban Ocon looks to be favourite to claim a race seat next season. He was reserve driver before he joined Manor ahead of the Belgian Grand Prix and retains the backing of Mercedes, who are happy to loan the Frenchman out to another team in order to continue his development. For Renault it would give them a French driver to spearhead its return to competitiveness -- a marketing win-win back home.
It is the other seat which remains of interest. Magnussen's recent drive to tenth in Singapore will have strengthened his claims for a seat -- he previously had scored the team's only points of 2016 in Russia. One interesting rumour to have surfaced in recent weeks is Renault buying Carlos Sainz out of his Toro Rosso contract -- though it would likely be deterred by a hefty price tag. Bottas and Perez should not be ruled out completely until they are confirmed at their current teams, while Daniil Kvyat could be an interesting consideration if he is not retained by Toro Rosso. Whatever happens, Renault's decision to wait until confirming the 2017 line-up has given it plenty of options up and down the grid.
Carlos Sainz has one of the two Toro Rosso seats for 2017, as Christian Horner confirmed in June. However, as the Spaniard had no say in the renewal, it adds weight to the Renault speculation mentioned above. Teammate Daniil Kvyat is still unsure where he will be next year, with his dramatic loss of form since being relegated from Red Bull at the start of the year leading to questions about his future. While Kvyat should not be discounted from other seats on this list he also should not be written off completely at Toro Rosso, with it clear he is still well regarded in the Red Bull programme.
There is only one man who can replace Kvyat: GP2 leader and Red Bull junior Pierre Gasly. Though the pair appear to be in a straight fight for 2017, a GP2 championship might just be too good for Helmut Marko to ignore.
With Sauber's new owners Longbow Finance linked to Marcus Ericsson's Swedish backers Tetra Pak, it looks like a safe bet to assume he will stay there in 2017 despite the recent admission he's talking with various teams about next season. That takeover will have been a welcome relief to both Ericsson and his teammate Felipe Nasr, as will the upgrades and recruitments which followed -- both suggesting renewed fortunes at the tail-end of 2016 but more importantly in 2017.
As for Nasr, he brings significant sponsorship of his own in the form of the Banco do Brasil branding and colours adorned on the car. With opportunities elsewhere looking increasingly limited for the Brazilian Sauber is likely to have an unchanged line-up next season.
Pascal Wehrlein seems like a logical choice for next year -- a Mercedes junior driver at a team supplied by Mercedes engines. Another year there gives the German plenty of time to develop out of the spotlight before a potential move up the grid in 2018, the final year of Lewis Hamilton and Nico Rosberg's current contracts at Mercedes.
If Ocon does in fact switch to Renault next season it would leave Manor with a vacant seat to fill. Rio Haryanto has retained his links to the team and may well return to the grid if he can find the relevant funding, while Nasr's name has also been mentioned as a candidate. Manor reserve driver Alexander Rossi's stock has risen significantly after his remarkable rookie Indycar season, which included victory at the Indy 500, but recent reports have suggested he could remain in that series and switch to Penske.
Romain Grosjean is all but certain to remain at Haas next season. The Frenchman has scored all of Haas' current points (28) and will remain in a prime position for a Ferrari drive in 2018 if he stays with the American customer team. Esteban Gutierrez's future is less certain -- the Mexican driver insists he will be in F1 next year but both he and Haas have refused to clarify whether he will stay. Recent mistakes at crucial moments -- such as his slow start off the line in Monza -- will not have aided his chances of staying on merit.
If he does not stay, Haas could well move for Ferrari academy and GP3 series leader Charles Leclerc. Team boss Guenther Steiner admitted in Belgium the team is not averse to housing a Ferrari development driver in order to groom him for a role at the senior team. American driver Rossi may be a driver of interest given his improved profile in the U.S. but it is unlikely Haas would take a risk on someone not affiliated with Ferrari for the seat alongside Grosjean.