Williams have refused to rule out a 2017 move for Jenson Button.
The Englishman, who started his career at Williams back in 2000, is expected to be replaced by McLaren at the end of the season.
Button, now 36, has picked up just five points from eight races so far this season,
'Button back at Williams is a great headline,' deputy team principal Claire Williams told Sky Sports.
'He started his career here, he's a world champion and extremely intelligent when it comes to building a team around him and helping the engineering side develop the car.
'Of course he is going to be an attractive proposition if he is available.'
Valtteri Bottas and Felipe Massa currently occupy the two Williams seats, with the team holding an option to extend Bottas' deal and Massa's due to expire at the end of the season.