The move shocked the F1 world when it was announced in February, and was a disappointing one for Mercedes, under whom Hamilton won six of his seven drivers' titles between 2008 and 2020.
It soon became apparent that Ferrari would be keeping Charles Leclerc with Carlos Sainz forced to look for another drive, and what seemed like a natural fit - Sainz to Mercedes to replace Hamilton - now looks to be a done deal.
Sainz 'close to an agreement' with Mercedes
"Carlos Sainz is close to reaching an agreement with Mercedes," Marca report, referencing La Gazzetta dello Sport and Corriere della Sera. "The Madrid driver doesn't have a seat for 2025 and there have been many rumours around him.
"If an agreement is reached in the coming days, his signing could be officially announced."
Sainz had previously claimed to be in negotiation with a number of teams, and the Spaniard, who won the Australian Grand Prix in March, would be in understandably high demand.
Ferrari is the fourth team he has raced for in F1, and his longest post after spells with Toro Rosso, Renault and McLaren.
It is understood Sainz is looking for a guaranteed two-year contract, with the option of a third, while Mercedes want to keep their options open for 2026, with an audacious move for Max Verstappen on their agenda.