Bernie Ecclestone has urged Williams to sign Robert Kubica, claiming the Polish driver will deliver and will "wake the team up".
Kubica completed a "successful" one-day test with Williams on Wednesday as part of an assessment plan to see whether he is capable of a full-time race seat alongside Lance Stroll.
Whilst others are in the running, including Felipe Massa, Paul di Resta and Pascal Wehrlein, Ecclestone believes Kubica would be their best bet.
"I think he can come back even stronger than before," the former F1 boss told Motorsport. "Mentally, I think probably he will be more aggressive: so I can only see good, good things for him."
Ecclestone believes he would be an asset for Williams and would boost their position which has fallen into a lull in recent years.
"If I were Williams, I would definitely try to persuade him to join. Maybe they are going to lose Felipe Massa at the end of the year, I should think he has probably had enough, and if Robert is on board then he might wake up a lot of people there.
"The team hasn't been performing as well as it should have done, and whether it is because of drivers or the team in general, I don't know. Nobody knows. So it would be nice to get a guy who should be quick in the car to find out."
