Is the 2018 driver market really all about the 2019 driver market?

Heard the one about Lewis Hamilton and Max Verstappen as Formula 1 team-mates?

And Sebastian Vettel swapping red for silver?

F1's 'silly season', the annual period devoted to rumour and speculation about impending driver changes, normally starts in early summer. This year has been no different. But there's been a twist: silly season for 2019 has also opened, confusing the picture for next year and adding a fascinating level of extra complexity in the driver market.

It's why so many leading seats in F1 are currently unsecured for 2018 at the halfway stage of the current campaign.

So who's where in 2018?
Here's what we know with any degree of certainty:

Lewis Hamilton is in the second of his three-year deal with Mercedes. Red Bull are adamant Max Verstappen and Daniel Ricciardo are fixed for 2018. Nico Hulkenberg signed a multi-year deal with Renault when he joined in November. Fernando Alonso is in the final year of his McLaren contract and has warned he wants a winning drive next year.

Just about everything else, however, is open.

Neither Ferrari driver is under contract for 2018. Valtteri Bottas only has a one-year deal with Mercedes. Carlos Sainz, to the irritation of parent team Red Bull, says it's "unlikely" he'll be at Toro Rosso for another season. Robert Kubica's comeback has stepped up a gear after he successfully passed an 'extensive' second test with Renault this week. McLaren have unofficially confirmed Stoffel Vandoorne for a second full season but there's been precious little conversation about who would replace Alonso if he departs.

What's delaying the 2018 driver market?
The answer is not 'what' but 'who'.

"Max Verstappen is holding up the whole driver market," said Sky F1's Martin Brundle in Austria. "He is the future. Somebody will want to nail him down and then build around him.These teams think a long way ahead."

Red Bull are adamant Verstappen won't be leaving Red Bull any time soon, stressing his contract for 2018 is watertight. "We will stay with the team for sure," Max's father, Jos, told Sky F1 at the Red Bull Ring. But 2019 may be a different matter.

"There is no doubt about it, there will be a bidding war, for some time now, behind the scenes between Ferrari and Mercedes to get Verstappen's signature on a contract," says Brundle.

The need to wait for Verstappen would seemingly point to another year of Kimi Raikkonen bridging the gap until Verstappen becomes available. But Sergio Marchionne's description of the Finn, who has scored less than half the points Vettel has contributed so far in 2017, as "a laggard" suggests the Ferrari boss doesn't possess unfaltering patience.

In any case, how difficult would it be for Ferrari to find a driver with the potential of improving on Raikkonen while accepting a one-year deal? Romain Grosjean and Sergio Perez, both free agents for 2018, would surely take any opportunity to drive in red no matter the terms attached.

Yet Verstappen may not be alone in delaying the market.

Rumours have abounded for weeks that Vettel, out of contract with Ferrari at the end of the year and still yet to re-commit, has some sort of pre-contract agreement with Mercedes, reputedly signed during the dark days of 2016 when Ferrari were a speck in the Silver Arrows' mirrors.

But the prospect of Vettel quitting Ferrari, even as a German driver to a Mercedes outfit perceived to be a 'German team', just when Ferrari have finally woken from their slumbers is surely remote.

The other, rather glaring, problem with the pre-contract speculation is that it doesn't make a great deal of sense: given he's free to go where he likes in 2018, why would Vettel have felt any need to commit, to any degree, to Mercedes or any other team? A four-time world champion will never be short of suitors so Sebastian had no reason to sign anything, this year or last, of commitment to 2018.

But while the detail may be iffy, the general thrust may be not and the intriguing fact of the matter remains that Vettel still hasn't signed a deal with Ferrari for next season. As Marchionne confirmed in Austria, "I've made it very clear that if Sebastian wants to stay, it's his option."

So why hasn't he signed? And what exactly is on offer - a short-term deal or a multi-year commitment?

More pertinently, is Vettel's dallying also the reason why Mercedes still have a seat free for 2018?

"'I would think Seb's got Toto [Wolff] in his ear trying to say extend for just a year and then he's probably got Ferrari saying it's three years or nothing," Red Bull boss Christian Horner mischievously suggested at Silverstone.

What's going on at Mercedes?
Unlike Ferrari, Mercedes do at least have one of their current drivers under contract for next season: Hamilton is contracted until the end of 2018. Valtteri Bottas, on the other hand, isn't.

"Valtteri is doing a good job but I don't think you should be rushed into a driver decision," said Merc boss Wolff in Austria. "The market becomes pretty interesting in 2019 and onwards and you just need to plan ahead what's happening."

Mercedes won't rush 2018 driver call

It's reasonable to assume Mercedes are giving due diligence to the possibility that, either this year or the next, Vettel and/or Verstappen could be on the market.

"Taking Sebastian out of the equation at this stage would be silly," admitted Wolff two months ago.

Then's the Lewis Hamilton question.

Throughout his career, Hamilton has made several contradictory remarks about driving for Ferrari before hanging up his racing gloves. Many in the paddock are convinced it will happen - and some have even reported as much.

Which may be why Mercedes have, if the rumours are true, lined up Vettel as an alternative.

A scenario in which Hamilton and Vettel swap seats in 18 months' time, and Mercedes' driver line-up for 2019 consists of Vettel and Bottas while Hamilton joins forces with Verstappen at Ferrari, is far from implausible.

Where does Alonso fit in?
The problem for Fernando is that he doesn't appear to fit anywhere at the top of the market.

Mercedes have all-but ruled out the Spaniard. Red Bull, where Sainz is first in line for any vacancy, have firmly closed the door. And despite admiration within the team for his talents, it's the view of Marchionne which matters most at Ferrari and Marchionne is on record declaring Alonso will not be returning.

Ferrari rule out Alonso for 2018
Mercedes consider 'team dynamic' around drivers
Red Bull close door on Alonso

Which seemingly leaves the two-time world champion, intent on remaining in F1, stuck at McLaren for at least another year.

Renault, currently appraising Robert Kubica's chances of a full comeback, are an option but the French team are no more likely to prosper than McLaren in 2018, and perhaps less so.

The stakes have been raised around McLaren's anticipated divorce from Honda by reports Honda have annulled their deal to supply Sauber in 2018. But, bottom of the Constructors' Championship, McLaren can't let concern about the message F1 would send out if Honda left the sport in six months' time influence their thinking - especially if a new engine deal would be sufficient to persuade their number one asset to stay put.

2018 may be the year of sitting still.

But for 2019, everywhere and everyone looks up for grabs.