According to Motorsport.com Carlos Sainz has signed a deal to join Renault which will set off a chain of events leading to Mclaren and Honda splitting.
It is believed that Renault will take Sainz, allowing Toro Rosso to switch to Honda engines early. This will, in turn, open up a supply for Mclaren with Renault.
At the Italian GP weekend, Renault said they need a good reason to end their deal with Toro Rosso and switch to Mclaren, this deal will give them a great line up with Sainz and Hulkenberg in the car.
It is not yet known when the switch will be made as there are suggestions it could happen as early as the Malaysian GP. If Renault is still unhappy with Palmer.
Should Mclaren and Toro Rosso switch engine suppliers the latter will also take gearboxes from Mclaren for the Honda engine, the system was in place for Sauber before they backed out of a Honda deal.
A Mclaren-Renault deal will likely be the turning point that convinces Alonso to stay with Mclaren for 2018.