Who holds the key to the F1 driver market?

With the 2017 Formula 1 driver market temporarily calmed following Ferrari's decision to stick with Kimi Raikkonen, McLaren and Sergio Perez have emerged as the ones capable of kicking it back into life. Based on their decisions, we will either see a flurry of activity, or a 2017 grid that largely resembles the status quo. But why?

McLaren already has Fernando Alonso signed up for next season, but it faces the same conundrum as last year on who will partner him - Jenson Button or Stoffel Vandoorne? And while it ponders that decision, Williams waits in anticipation.

Perez may well have a contract to drive for Force India next season, but he says can leave the team if his sponsors choose to take their prodigious backing elsewhere. Renault wants him and it is believed Williams does, too. So that leaves three teams hanging on his decision.

Taking McLaren first, the Woking-based team plans to wait until September before sitting down with Button and Vandoorne to talk about next year.

McLaren made Vandoorne wait for a first full-time F1 ride by keeping Button on this year and it will be wary of doing the same again, given how highly-rated the 2015 GP2 champion is. The Belgian feels ready and wants his shot at F1. How long will be willing to hang around on the sidelines?

Vandoorne is more of a long-term option than Button, but ahead of next year's technical regulation changes, the benefits of keeping the latter for his experience and good relationship with McLaren and Honda are clear.

It makes sense for Button to wait and see what can be done with McLaren as the team's improvement this season and scope for Honda to make gains next term - with the abolition of the engine development token system - could give him the best chance of returning to the podium.

The delay in finalising plans at McLaren creates a bottleneck, with Williams most affected as it is keen on luring Button back to the team with which he made his debut in 2000.

Deputy team principal Claire Williams described Button as a "very attractive" proposition. Williams would love to have him back, but not at any price.

It's a numbers game for Williams. It is set to finish at least one place lower in this year's constructors' championship than in 2015 and therefore lose a valuable chunk of prize money. Last year, the difference between third and fourth was around $7million.

Combine that with the impact of Brexit on sterling increasing the amount of money it pays for its Mercedes engines - a bill measured in euros - and the challenging sponsorship marketplace, and that leaves it facing a sizeable hole in its 2017 budget, believed to run into the tens of millions of dollars.

It has also emerged the commercial benefits of bringing in Button are not as attractive as hoped. That would be something Williams would have to leverage if it is to find the money to fund his services.

That said, if McLaren chooses not to keep Button, the 2009 world champion could be flexible on his price as Williams suddenly becomes arguably the best option if he wants to stay in F1.

Williams wants to extend Valtteri Bottas's stay into a fifth season, but it is believed activating its option on the Finn will require a rise in his fee, which presents an obvious problem.

Bottas, though, is short on options himself with seats at the top three teams now closed off. He has spoken of wanting to stay at Williams because he has unfinished business - and it represents a solid option based on what is left available, so perhaps a deal can be done.

Williams is in a reasonably strong position as it arguably has the best seat available based on current form, so it is unsurprising that it has attracted a lot of interest from drivers.

Pastor Maldonado, for instance, is understood to have contacted his old team to see if there was an opportunity next season, but such a move is very unlikely.

Felipe Nasr is under consideration for the second seat and is an interesting prospect. The Brazilian was Williams's reserve in 2014 and has financial backing of around $10million.

Keeping Felipe Massa is not believed to be high on the Williams priority list, with figures inside the team questioning whether he can deliver consistently.

But the Brazilian has said money is not as important any more, so perhaps a cut-price Massa who is comfortable with the team is not such a bad option. Williams technical director Pat Symonds has said he would be very happy if the line-up remained unchanged next term.

And then there is Perez, who Williams is also interested in, as that would help its bank balance. It's a realistic option for the Mexican but he is known to want to head to a manufacturer team, which he believes is a more favourable long-term prospect.

That's where Renault comes in, as the French manufacturer wants him. But a move to Enstone will require some pain early on as it rebuilds. In contrast, Williams is a proven top four team and has shown in the past that it is capable of responding well to changes in the regulations.

If Perez joins Renault, it appears keen on making Esteban Ocon his team-mate. Ocon has impressed on his outings in FP1 this year and has since joined Manor in place of Rio Haryanto for the remainder of the season. That lets Renault fully evaluate him and assess his capabilities against the highly-rated Pascal Wehrlein.

Perez leaving Force India leaves a decent midfield seat vacant and Wehrlein appears to be in pole position to get it. The German has impressed at Manor, particularly with his race performances, and has tested twice for Force India in the past.

It would make sense for Mercedes to place him in a team that has this season emerged as a contender for the title of its best customer runner, closing on Williams in the constructors' championship.

With seats filling up at the upper end of the midfield, there will be a knock-on effect lower down, as drivers scramble to fill the remainder and ensure they haven't missed out when the music stops.

Marcus Ericsson says he is looking at other options but given he is believed to have ties with Sauber's new owners Longbow Finance, he is likely to stay put next year. Nasr's financial backing would be very useful to Sauber and therefore it must be willing to wait to see how the interest from Williams pans out.

Toro Rosso is perhaps immune to what the rest of the field does, as Red Bull boss Dietrich Mateschitz and his motorsport advisor Helmut Marko will make the call on who partners Carlos Sainz Jr. Team boss Franz Tost has made it clear he wants to keep Red Bull refugee Daniil Kvyat, but history has proved only the two aforementioned men will have the final call.

Haas team boss Gunther Steiner will not consider his driver line-up until after the European season has finished next month, but Romain Grosjean is likely to stay on for another year. That would keep a path to a shot at Ferrari open with Raikkonen only re-signing on a one-year deal. It also gives him another year to assess Renault's progress, with a return to Enstone a distinct possibility.

The second Haas seat is trickier. Development driver and Ferrari protege Charles Leclerc has impressed but he must win the GP3 title - which he currently leads by three points - to ensure he gets enough points to qualify for a full superlicence. Signing the Frenchman would sit well with Haas's technical partner and engine supplier Ferrari.

Esteban Gutierrez has struggled this year and a source within the team has said he would be surprised if he keeps his seat. The Mexican cryptically said last month he knows what he'll be doing next year, adding it will be in F1, but refused to give more details.

That just leaves Manor, which will likely be the last to finalise its 2017 line-up. It is expected to hold out for the best deal financially to further stabilise its position in F1.

So it appears we're not far off the remaining pieces of the puzzle falling into pace - it just needs McLaren to sit down with its drivers and Perez's sponsors make a call on where to divert their money to get the ball rolling. An intriguing few weeks lie ahead.