London - Formula One's post-season shake-up took another spin on Tuesday with Williams announcing the departure of technical head Pat Symonds while Valtteri Bottas moved closer to Mercedes and Felipe Massa's retirement looked to be coming to an end.
Williams said Symonds, 63, would be leaving on 31 December, amid speculation that Paddy Lowe is set to join Williams from dominant world champion Mercedes to take up a similar role.
Symonds, who worked with the late Brazilian great Ayrton Senna at Toleman in the 1980s and seven times champion Michael Schumacher at Benetton in the 1990s, joined Williams in 2013.
Deputy principal Claire Williams said: "Pat's appointment was the start of a major restructuring exercise, and he has been pivotal in reshaping Williams into what is a much stronger racing team today. We now look to the future and will be announcing details regarding the team's technical leadership in due course."
Symonds left Formula One in 2009 when his then employer Renault was embroiled in a race-fixing scandal after it emerged that it had ordered Brazilian Nelson Piquet to crash deliberately at the 2008 Singapore Grand Prix. He returned as a consultant in 2011 with Virgin Racing, now Manor.
His departure from Williams means the former world champion, which finished fifth in 2016, will start the year with several new faces.
Bottas favourite to replace Rosberg
Canadian Lance Stroll, still just 18, will be making his race debut but his team mate remains uncertain following the surprise retirement of Mercedes' newly-crowned world champion Nico Rosberg.
Bottas, who has been at Williams since 2013, is the favourite to replace Rosberg as Lewis Hamilton's team-mate. Mercedes team boss Toto Wolff is also involved in the Finn's management.
If Bottas leaves, Brazilian veteran Massa is tipped to come back out of the retirement he started - somewhat reluctantly when it became evident there was nowhere else for him to go - at the end of November. Media reports indicated Massa, 35, had agreed the terms for a return to Williams should Bottas go. Massa is currently on holiday, his manager Nicolas Todt was not immediately available and neither Williams nor Mercedes has confirmed anything.
Williams uses Mercedes engines and a discount on them, coupled with Lowe possibly being allowed to join the team earlier than scheduled, is likely to sweeten any deal for Bottas. Mercedes, which is believed to have former Ferrari technical head James Allison lined up, has said there will be no announcement on its driver line-up until the new year.
Giovinazzi appointed Ferrari reserve driver
Meanwhile Ferrari has announced that Italian Antonio Giovinazzi, 23, will be its Formula One reserve driver in 2017. Giovinazzi, who is likely to drive the car in testing during the campaign as well as carry out work in the simulator, was runner-up in the GP2 feeder series in 2016 this year.
President Sergio Marchionne also announced at a Christmas lunch for the media at the Maranello factory that Ferrari's 2017 Formula One car would be unveiled on 24 February.
The team failed to win a race in 2016, after three victories in 2015, and Marchionne said there were still "many things missing. But the team is the team and it was put in place over a period of years and we're not about to change it now.
"Our working practice is already different to what it was back in August, which is when Mattia Binotto took over the reins as chief technical officer...put in the work and the results will come."
Ferrari has former world champions Sebastian Vettel and Kimi Raikkonen in an unchanged lineup for 2017.
Team principal Maurizio Arrivabene said: "Sebastian was here yesterday, working in the simulator and he repeated the fact that he wants to win with Ferrari, It's up to us to give them a car capable of doing that."