Claire Williams has admitted her team is open to the idea of releasing Valtteri Bottas to Mercedes, but only if an "experienced, credible alternative" was available to replace him.
Bottas is currently favourite to land the Mercedes seat vacated by the retiring Nico Rosberg, with the world champions approaching Williams about the Finn's services earlier this week. Though that approach was rebuffed by Williams the team is preparing for life without Bottas, with L'Equipe this week reporting it is in "advanced talks" with Felipe Massa about reversing his decision to retire from F1 this year.
Deputy team boss Williams has appeared to confirm those Massa reports by saying it will not stand in the way of Bottas moving if she can ensure the team gets a viable replacement.
"I'm delighted to see that a team like Mercedes lists Valtteri as a potential replacement for Nico," Williams told BBC sport. "We have always known Valtteri is one of the sport's key talents and are proud that the championship leaders recognise this.
"However, Williams has its own ambitions and we must always ensure we give our team the best opportunity to move forward. Any changes would only be made if Williams remains in a strong position to compete and develop in 2017.
"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."
The L'Equipe report also stated Mercedes is offering Williams an £8.4 million discount on its engine supply for next year. According to the BBC, Williams is "playing hardball" with Mercedes as it knows the world champions have a very narrow list of candidates given the timing of Rosberg's retirement.