Robert Kubica has not denied speculation that he is now in the running for the Williams race seat for 2018.

Earlier, the former BMW and Renault driver was eyeing a return to Formula 1 next year with Renault, following a spate of tests.

However, Germany's Sport Bild said that Renault ultimately opted for Carlos Sainz, after Kubica's permanent arm injury affected his pace over 'long runs'.

Kubica, and his management including retired world champion Nico Rosberg, have therefore shifted their sights to Williams.

The British team look set to oust the re-retiring Felipe Massa, and are apparently considering Kubica, Paul di Resta or Jolyon Palmer as his potential replacement.

When asked about the Williams reports, Kubica told Poland's Przeglad Sportowy: "Thanks to the tests with Renault I was able to find out that I can drive a Formula 1 car.

"Now we are working on a solution for the future. Whether it will be in Formula 1 or somewhere else I don't know yet. But I am trying to find a solution that will allow me to continue what started with my first test in June."

"In recent years I have had to be patient, and I have approached this whole situation rationally and not emotionally.

"Hopefully everything will work out as I hope and in the near future I will have some positive information."

According to some Polish media reports, Kubica's Williams chances - and potential forthcoming track test - are being funded by a personal sponsor.

"I must say that this is not true," he insisted. "My future does not depend on what my sponsors or partners will do."

As for the rumours he struggled physically on the 'long runs' with Renault, Kubica said: "I'm glad there are rumours, because they are about me being in the car compared to the six years when I was not!

"Thankfully those who make the decisions to do not pay attention to rumours and speculation."

The current campaign continues this weekend with the Malaysian Grand Prix.