Felipe Massa could return if Valtteri Bottas leaves Williams

Mercedes have contacted Williams to discuss the possibility of releasing Bottas to replace Nico Rosberg after the world champion's shock retirement.

And while Williams have rejected the initial offer – which included a reduction in the cost of its 2017 engine supply as well as the opportunity to run Mercedes reserve Pascal Wehrlein – it is believed that a second proposal is being formulated.

Williams are keen to hold on to Bottas because of his experience, given that his 18-year-old team-mate Lance Stroll will be making his F1 debut. But deputy team principal Claire Williams has revealed that the team would be willing let Bottas leave "if an experienced, credible alternative was available".

The team are thought to be conscious of not standing in the way of Bottas making progress in his career, having brought him through their junior programme prior to giving the Finn his F1 debut in 2013.

But in order for a deal to happen, Williams want to secure a driver with experience to ensure they does not drop further down the constructors' championship.

And Massa has now emerged as the leading contender to replace Bottas, should Williams release him.

Massa announced his retirement at the end of last season, bringing an end to a career that spanned 14 years. However, he told Autosport that he still wants to compete and is aiming to secure a full racing programme next year.

Massa would provide the necessary experience Williams requires next season, should he decide he wants to return for a 15th year.

No announcement is expected until the new year, with Mercedes having said it will not reveal its plans until January 3 at the earliest.

Bottas slipping into Rosberg's vacant seat looks increasingly likely to happen. And if he does, then who better to come in than the vastly experienced Massa?

The Brazilian's retirement was a disappointment for the sport and even he feels like it's come too soon, so there won't be many complaining about a comeback.

His panache behind the wheel and that incredible recovery after his accident have deservedly made him one of the most loved drivers on the circuit.

But if he doesn't get the move, then at least he's already had the tear-filled farewell at his home track.