Formula 1 could be set for a dramatic shake-up as the race to secure engine deals for the future hots up.
There is now even the prospect of a renewal of some iconic F1 partnerships from the past, with both Lotus and Williams leading contenders to land Honda deals.
HONDA SEEKING MORE
It has been known for several months that Honda would be linking up with McLaren in 2015, with this week's confirmation coming just a few days after the Woking-based outfit allowed an option it had with Mercedes for that season to lapse.
But while a deal with McLaren has been Honda's main target for some time, it has already been evaluating other teams it could link up with on its F1 return either for its first or second seasons back.
Such is the effort that will be needed to get ready for 2015 that it may elect to focus solely on McLaren for that season, but by 2016 it will definitely be ready to expand its programme.
AUTOSPORT has learned that enquiries about customer partnerships have been made to at least one top team, with Lotus and Williams believed to be its favoured choices.
Options elsewhere at Sauber and Marussia appear unlikely, with both outfits believed to be closing in on deals for Ferrari customer units.
While the prospect for Williams or Lotus of joining the Japanese manufacturer on its new F1 push is attractive, securing a customer supply deal from 2015 or 2016 would mean that they would need short term engine deals for the next one or two years.
F1's current manufacturers previously made it clear that they would prefer longer term contracts - for at least five years - which will make it far from easy to get agreement on something much shorter.
However, AUTOSPORT can reveal that Lotus and Williams supplier Renault's stance on its plans has now changed, with the company now determined to trim its partners.
RENAULT WANTING LESS
Before Honda's F1 return became a reality, there was the possibility that Renault could supply up to six teams on the grid, with Ferrari and Mercedes both eager to limit their supply to just three.
The arrival of a fourth manufacturer, however, and a change of approach from new management, means the French manufacturer wants to reduce its involvement long term to just three teams.
It currently has no formal contracts in place for next year, but is in negotiations with Red Bull, Lotus, Williams, Caterham and Toro Rosso.
Renault Sport's F1 president Jean-Michel Jalinier told AUTOSPORT: "It is known in the paddock that we are negotiating with five teams, but I am not sure we are going to go through with five teams.
"With three teams we would be happy, and we can run the business nicely.
"But there will only be three suppliers in 2014, so it is not possible that all of us have just three teams. So probably we will have to go with more.
"My guess is it will be between three and five. Not less than three, because that doesn't make sense, but five, I don't know..."
While long-term deals with Red Bull, Toro Rosso and Caterham appear to be a formality, Renault's longer-term ambitions could well result in it being more amenable to short-term contracts with either Williams or Lotus if they are keen on pursuing the Honda route.
MERCEDES ANOTHER OPTION
But the engine choice for those two teams is not just restricted to a Renault or Honda future, for Mercedes is also an option as the German car manufacturer now pushes to find an extra partner.
High-level sources at Mercedes have confirmed to AUTOSPORT that it wants to supply a fourth team next year beyond its works outfit, McLaren and Force India.
Its key targets are also Williams and Lotus, although it would prefer a longer-term deal for up to five-years.
While such a deal would then rule either outfit of an early switch to Honda, one of the key benefits over sticking with Renault would be financial, as the Mercedes package cost is believed to be below the €20-23 million figure per year that the French manufacturer is currently proposing.
There appears then to be three options for Williams and Lotus: commit long term to Renault; commit long term to Mercedes; or go the Honda route and agree a short-term contract extension with their current partners.
Jalinier believes the picture should become much clearer in the next couple of weeks.
"We expect that by Monaco, with another two weeks work, we can have something ready - or at least have a better view of what will be the situation," he said.