Robert Kubica is to undertake an extensive assessment of his driving capabilities in a second Renault Formula 1 test that will determine if a full comeback is possible, the team has confirmed.

A second test for the Pole had been reported earlier in the week after he impressed at his first run in an F1 car for over six years, completing a full simulation of a race weekend in just a single day with 115 laps of the Valencia circuit around a month ago.

This will likely mark the most critical evaluation of Kubica's potential and if successful could well earmark the 2008 Canadian Grand Prix as an option for Renault or any team for 2018.

“Whilst the first day of testing at Valencia was no more than to let Robert get reacquainted with the feel of driving again, this second test will be to assess his capabilities to return to the highest level of competition," managing director Cyril Abiteboul said when revealing the test.

"This is a new phase in his personal and professional journey and we are proud to support him in the form of lending our infrastructure at Paul Ricard that is suitable for professional and non-professional drivers.

"There are still many hurdles for him to overcome, and he knows better than anyone else that only his performance will determine if he can one day return to being a professional driver.”

During an appearance for Renault driving the 2012 car at the Goodwood Festival of Speed last weekend, Kubica claimed his chances of a return had dramatically improved from 20 percent to as high as 90 percent.

"My first target was to see if I could be capable of doing it," he added. "So this is more or less done.

"Second, let's say, realistically talking, is raising the game slowly and step by step. F1 is a tough competition and I have been away from racing a long time."