Pascal Wehrlein has joined Sauber ahead of the Formula 1 2017 season. The German's departure from Mercedes leaves the door open for Williams driver Valtteri Bottas to take Nico Rosberg's vacant seat with the world champions.

Wehrlein will replace the outgoing Felipe Nasr and partner up with Marcus Ericsson at Sauber, who use engines supplied by Ferrari. The 22-year-old's departure gives a huge indication as to where Bottas' future may lie, as he was believed to Mercedes' reserve option.

Wehrlein is part of Mercedes' young driver programme and Sky Sports claims he was considered by Force India, who eventually plumped for Esteban Ocon to replace Nico Hulkenberg. Bottas' replacement at Williams looks likely to be Felipe Massa, with Mercedes deputy team principal Claire Williams hopeful of an announcement by the end of the week.

"It has been dragging on and I think everyone wants to know, probably more who is going to be Lewis [Hamilton's] team-mate next year, and of course whenever Nico made his announcement we knew the call was probably going to come from Toto [Wolff, Mercedes team boss]," Williams said.

"It is a great opportunity for Valtteri and he has given a lot to Williams. We've always said if we can make this happen on terms that are positive for Williams then it is probably the right thing to do.

"No-one needs or wants a driver in your team that really wants to be somewhere else. It is not nice either to stop a driver who has such a great opportunity, particularly at this point of Valtteri's career, but it has to work for Williams and that is what we've been working hard on over the past six weeks. We are nearly there, we are at the tail end of it and hopefully we'll be able to make an announcement this coming week."