Williams driver Felipe Massa has said he is retiring at the end of the season, ending a 15 year career in the sport. The Brazilian had been due to retire at the end of last season but was brought back into the sport by Williams as a last minute replacement for Valtteri Bottas who left to fill the spot left by the retiring world champion Nico Rosberg.
Massa had been in the running for a Williams seat for next season, and had been quite vocal in his belief that he would be the most suitable driver for the team heading into next season, but has now said his decision is final to retire.
"As everyone knows, after announcing my retirement from Formula 1 last year, I agreed to return this season to help Williams when the call came," said Massa in a team statement.
"I have now enjoyed four great years with the team, but my career in Formula 1 will finally come to an end this season. Once more, I would like to say a big thank you to everyone who has supported me throughout this time: my wife and my father, my whole family, my manager Nicolas and all my friends, colleagues and sponsors.
"I would also like to add a huge thank you to all of the fans who have been incredibly supportive and passionate over the years. I take so many great memories with me as I prepare for my final two races in Brazil and Abu Dhabi, and although they will be emotional, I am looking forward to ending on a high note and preparing for a new chapter in my career."
It is understood that Williams is inclined to hand Robert Kubica a race seat for 2018, but want to test him further to fully evaluate his potential. Williams reserve driver Paul Di Resta is also a high candidate, impressing the team when he filled in for an unwell Massa in Hungary earlier this year.
Former Red Bull and Toro Rosso driver Daniil Kvyat and Mercedes junior Pascal Wehrlein are also both being considered. However, these are less likely options as Williams' title sponsor Martini is believed looking for a driver over the age of 25 to partner Lance Stroll.
Sam Gale and Fergal Walsh
Bahrain International Circuit - Winter testing