Valtteri Bottas visited Mercedes factory before Christmas

Valtteri Bottas visited the Mercedes factory before Christmas, giving the firmest indication yet that he is set to fill Nico Rosberg's vacant seat.

Bottas has emerged as the frontrunner to replace the retired 2016 world champion, with Williams agreeing a deal to bring back Felipe Massa before Christmas to take the Finn's seat. Mercedes has delayed an announcement until January 3 at the earliest but, according to a Motorsport.com report, Bottas visited the factory in the days leading up to December 25.

The report suggests Bottas visited the factory to try out the cockpit of the team's 2017 car and to help plan his seating position, as well as running through technical preparations with the engineers he could work with next year. It suggests Mercedes is already preparing for life with Bottas for the new campaign.

The confirmation of who will partner Lewis Hamilton would likely lead to the other pieces of the driver puzzle falling into place, as Sauber stalled talks with Mercedes junior Pascal Wehrlein after Rosberg's announcement. Wehrlein's limited F1 experience, which tallies as just 21 races with Manor last year, likely counted against him when Mercedes was considering Rosberg's replacement. Manor remains the only other team with empty seats, though is unlikely to confirm drivers until nearer to winter testing.