Felipe Massa has reportedly agreed to come out of retirement to rejoin Williams next season, if Valtteri Bottas departs to replace the retired Nico Rosberg at Mercedes.
The 35-year-old Brazilian announced his retirement in September and brought the curtain down on his 14 years in Formula One at the end of the 2016 campaign, but now seems set for a u-turn.
Williams hinted last week that they could let Bottas join Mercedes in 2017 if they could tempt Massa back.
Deputy team principal Claire Williams told BBC Sport: 'If we did allow Valtteri to leave, we would only do this if an experienced, credible alternative was available, such as someone like Felipe Massa, for example.'
Reports in Italy, Brazil and Britain on Tuesday evening claimed Massa has indeed been persuaded to reverse his retirement decision, with the matter now dependent on Bottas' next move.