Now that three races have passed, giving the paddock time to digest the news of Casey Stoner's shock decision to retire and consider what effect it will have on the future line up of the MotoGP grid. The riders' representatives have been very busy at the past few races, putting out feelers to factories and teams, weighing up opportunities and gauging the market value of their riders. With summer approaching, Silly Season for 2013 is very much open.

Two more decisions have accelerated developments, and drawn the lines of the 2013 season a little more clearly. Firstly, Jorge Lorenzo's decision to stay with Yamaha for next season - "if Jorge wants to win championships," Lorenzo's team boss Wilco Zeelenberg had said at Barcelona, "his best option is to stay at Yamaha." The strength of the team and the state of the bike do seem to have been the key criteria for Lorenzo's decision, the Spaniard opting for performance over financial gain.

The second development is the dropping of the Rookie Rule, preventing newcomers into the MotoGP class from going straight to the factory teams. The rule was popular with some team owners, but it also created major headaches for them: a big-name rookie like Marc Marquez does not come alone, but brings a small army of sponsors, advisers, mechanics and assorted hangers on. Room has to be made for these people and these sponsors, and long-term relationships have to be put aside to make way for them, which team managers then have to try to reestablish a year later once the rookie has gone. The abolition of the Rookie Rule clears the way for Marc Marquez to enter the Repsol Honda team, but it also opens up opportunities for other rookies at Yamaha or Ducati.

With these developments in mind, we can start to take a look at the current state of the market, the range of options open to riders in MotoGP, and what bikes may be on the grid for next season.

The Bikes

Though little is as yet know about who will be riding the bikes, we do know a few things about what will be available. IRTA secretary Mike Trimby confirmed to me that there will probably be 24 bikes on the grid in 2013. "We have 24 entries from very strong teams," he said. It looks likely that over half of those bikes will be CRT machines: though the original proposal allowing just four bikes per manufacturer looks likely to be dropped, having 12 factory prototypes on the grid is an improbable prospect.

Yamaha is the only known quantity here, the Japanese manufacturer fielding two bikes in the factory team and two bikes in the satellite Monster Tech 3 Yamaha squad. Whether Honda have four bikes or more depends in part on what Valentino Rossi decides to do; a fifth bike could be made available for Rossi should he decide to leave Ducati and set up a team of his own; if not, Honda will have the two factory bikes plus a single bike each at Gresini and LCR.

Ducati is the big conundrum. Ducati team boss Alessandro Cicognani told me at Silverstone that the plan was to continue as they are, with two factory machines and two satellite bikes, but with Pramac facing financial difficulties and Karel Abraham deeply unhappy on the Ducati, they may not have customer to lease their bikes. "Pramac is not an issue," Cicognani assured me, though he recognized that the price structure may have to change to retain the satellite teams. "If we find a solution to keep them, we may have to do something about the price," he said.

Others outside Ducati do not share his optimism. Inside both IRTA and Dorna, the Bologna factory is widely expected to field just the two-man factory team, and no satellite machines at all. With no satellite Ducatis available, limiting factories like Honda who are willing to supply more bikes does not make much sense. Expect there to be 10 or 11 prototypes on the grid, with the rest composed of CRTs.

The Certainties

Though we are just one third of the way through the season, there are already a few contracts signed. Jorge Lorenzo has signed a two-year deal with Yamaha, seeing him through the 2014 season. Lucio Cecchinello has a two-year contract with Stefan Bradl, meaning the German will be at LCR for 2013 as well. And Herve Poncharal signed a deal with Bradley Smith two seasons ago, putting Smith on the Tech 3 Moto2 bike this season with the promise of a MotoGP ride for 2013. What this means is that Smith will take one of Tech 3's two satellite Yamahas, leaving a long line of candidates for the second machine.

The Ninety Percenters

Though the list of certainties is very short at this stage, there are a number of names we can start to pencil in in a few places. First and foremost, of course, is the name of Marc Marquez, who will slot in to the Repsol Honda squad. No contract is yet signed, and talks are still ongoing, but with both Repsol and Honda firmly backing Marquez, it is inconceivable he would end up anywhere else. It is just a matter of time before that contract is signed.

The second seat alongside Marquez is a source of much speculation, most of which centers around the question of whether Valentino Rossi will elect to race for Honda or not. But those placing Rossi alongside Marquez at Repsol Honda are being a little premature: HRC insiders are very positive about Dani Pedrosa, and much less complimentary about Valentino Rossi. Rossi's autobiography, in which he criticized Honda's culture, left a bad taste in the mouths of HRC executives, and though the management has changed significantly since then, there are plenty of Honda employees who would like to keep Rossi out of the factory team.

Dani Pedrosa, on the other hand, is both highly rated and greatly appreciated inside Honda, HRC bosses having been impressed by the development work he did on the 2010 bike, turning it round from a fast but ill-handling pig into something very refined indeed. The bike was in pretty good shape once Casey Stoner arrived, easing the path for the Australian to dominate the 2011 season. Talks are currently underway between Pedrosa and Honda, and the Spaniard is reportedly confident that a deal will be done in the next few weeks.

At Ducati, Nicky Hayden looks certain to extend his contract with the factory team. The Kentucky Kid is very popular with the Bologna factory: he has regularly matched and beaten his teammate Valentino Rossi, and he and crew chief Juan Martinez are helping define the direction of development for the team. Hayden is a tireless PR worker, and most importantly of all, he helps shift product in Ducati's key market, the USA. A new contract for Hayden is just a matter of time.

The Million Dollar Question: Whither Valentino?

The real mystery for 2013, though, is what Valentino Rossi will do. Does Rossi stay at Ducati and continue to attempt to make the Desmosedici competitive? Does he team up with Gresini and take a factory-spec Honda to make an alternative Italian Dream Team? Or does he approach Yamaha for the second seat alongside Jorge Lorenzo?

All three options have risks associated with them. If Rossi stays at Ducati, he is dependent on the Ducati Corse department, under the leadership of Filippo Preziosi, being able to build a machine that is competitive, at least in the hands of a rider like Rossi who needs a solid front end. If he goes to Gresini, or a private Honda team, he has to rely on the goodwill of HRC to provide him with a full factory-spec RC213V, and hope not to be too far behind developments in the Repsol squad. And a return to Yamaha would invariably mean playing second string to Jorge Lorenzo, the man who Yamaha have made it clear is their future.

At the moment, all we can do is guess at Rossi's intentions, as the Italian himself is playing his cards very close to his chest. At Barcelona, Rossi told the press that for now, his priority was making the Ducati competitive, though he was careful not to mention whether he meant this year or next. After a dismal 9th place at Silverstone, a dejected Rossi was a little more open. The only thing that mattered, he told the media, was having a competitive bike. Everything else was subsidiary to that. The question is whether Rossi believes the Ducati can be competitive. Much will depend on the modified engine due to be tested this week by Franco Battaini at Mugello, and then by Rossi and Hayden after the Italian Grand Prix in four weeks' time. If that fixes the aggressive power delivery and its associated understeer, then Rossi may stay. If it doesn't, the marriage is over.

Last year, Rossi seemed determined to stay at Ducati and fix the bike, to ensure his place in history as a man who can take a troubled bike and turn it around. Now, Rossi seems more like a man who just wants to win again, whatever it takes. The constant failure of Ducati to give Rossi what he needs - and Rossi to give Ducati feedback they can work with - is starting to take its toll and wear the Italian down. Nowhere is that more obvious than in the rain: on Friday morning's wet session, Rossi looked like the nine-time World Champion of old, able to put the bike where he wanted and find speed wherever it was available, topping the session with ease. Once the track dried, the imposter who apparently lives in Rossi's leathers was back, Rossi rolling around in the lower orders of the factory prototypes, in a different postcode to Jorge Lorenzo, Casey Stoner and Dani Pedrosa, the men who should be his equals.

If Rossi leaves, he faces a stark choice. A Honda may not necessarily be his preferred option, the RCV suffering front-end chatter and an aggressive power delivery, though nothing compared to the Ducati. A Yamaha would suit Rossi better, allowing him to exploit his greatest strengths - corner entry and braking, where he can dive underneath an opponent and then hold them off on the exit - and making him immediately competitive. But a satellite ride on a Yamaha is out of the question - Herve Poncharal has more than enough problems trying to select a second rider into his team, without the added complication of housing Valentino Rossi and his entourage - and so his only hope will be the factory Yamaha seat alongside Jorge Lorenzo. I have not spoken to Lin Jarvis about Yamaha's feelings towards Rossi yet; I hope to do so at Assen. We may get a clearer sense of the factory's attitude towards Rossi then.

Open Question Marks

The second seat at Yamaha is the hotly contested ticket. Ben Spies needs to radically improve his results if he is to retain his seat at the factory, and he does not have much time to do so. The American bears only some of the blame for his miserable form, much of which is down to just plain bad luck. At Qatar, he had a cracked subframe, at Jerez, he did not have a set up he was comfortable with, a situation which was remedied at Estoril. At Le Mans, a slide at the start damaged his visor , and with it his chance of a decent result. At Silverstone, a blistering rear tire left him struggling for grip and running a damage limitation exercise, rather than being competitive. But at both Estoril and Barcelona, Spies has made some very costly mistakes when running at the front, and those mistakes are the kind which are not easily tolerated. Spies has proven he is fast during practice and qualifying, but he needs to translate that speed into a string of good results during the races.

What Spies has going in his favor is his passport; the US market is key to Yamaha's strategy, and Yamaha USA want a figure they can sell. Spies' marketability is good, though at the moment, the man on the cover of the magazines is double AMA Superbike champion Josh Hayes, racing a Yamaha R1 in the DMG-run series. Where Spies goes if his contract is not extended is open to speculation.

And speculation is all that there is concerning the other factory prototype seats. The second Tech 3 seat is immensely popular, but with both Cal Crutchlow and Andrea Dovizioso performing outstandingly well, Herve Poncharal has an embarrassment of riches at the moment. Tech 3 should be able to pick and choose who they want on the seat, and with an inexperienced rookie on one bike, they will want the most competitive rider available on the second. Whether that is Crutchlow, Dovizioso or even Ben Spies if he's available remains to be seen.

If Rossi leaves Ducati, then that leaves perhaps the biggest conundrum of all: who to put on the second Ducati? Cal Crutchlow has already said that he is not afraid of the bike, and that he believes his riding style would suit the Ducati, as his resembles that of Casey Stoner. Stoner disagrees, and if the experience of Valentino Rossi teaches us anything, it is that the switch from the tight front-end, high corner speed Yamaha to the uber-powerful, rear-focused Ducati is probably the hardest to make in MotoGP. If anyone's style resembles that of Stoner it is his teammate Dani Pedrosa, or perhaps Moto2 golden boy Marc Marquez; they both get their bodies a long way off the bike and lever the bike upright onto the fat part of the tire very early in corner exit, the way that Stoner does and did on the Ducati.

According to Spanish publication Motocuatro.com, however, it is another Spaniard that Ducati are chasing. Motocuatro believes that it is Pol Espargaro that Ducati are pursuing, in the hope that a young, inexperienced rider can master the peculiar skillset that it takes to ride the Ducati competitively. That looks likely to prove an idle hope, however: what made the Ducati fast was not Stoner's lack of experience with Japanese-style bikes, it was his supernatural ability on a motorcycle, and his hypersensitive throttle control and balance. Stoner won despite the weaknesses of the bike, not because he could exploit its strengths. Improving the bike to make it easier to ride is a faster route to success than signing a string of young riders in the hope of striking it lucky with an extraordinary talent, as they did with Stoner.

The next three races will be crucial for Silly Season, and announcements are likely to start coming thick and fast, especially after Mugello and Laguna Seca. Before that, there is much hard bargaining to be done, and many options to be explored. There will be surprises, but mostly there will be rumors, speculation, and downright lies. Expect a lot of MotoGP writers to get it very very wrong, and a few to get it right. I am expecting to find myself firmly in the first camp, rather than the latter.