Although Sebastian Vettel only announced he will be leaving Ferrari at the end of the 2020 season on Tuesday morning, in less than 36 hours Sainz and Ricciardo are on the brink of completing their respective moves.
GPFans revealed late Wednesday morning that Sainz was all but confirmed at Ferrari, whilst further suggesting Ricciardo would fill the vacancy at McLaren
It is understood the only hold up in the two announcements being made is that McLaren must formally release Sainz from his contractual obligations before they can announce the Australian as his replacement.
While the story has accelerated rapidly since Vettel's initial announcement, the negotiations have been taking place for some time.
During pre-season testing, Ferrari team boss Mattia Binotto had said he expected to have his 2021 driver pairing confirmed by the time of the Spanish Grand Prix, an event that was originally due to take place last weekend on May 10.
The timing of that original announcement would now appear to make sense.