Robert Kubica returns to action in crucial Williams test

ABU DHABI -- Robert Kubica has returned to duty for Williams in a crucial test which may well determine whether he will be the team's full-time driver in 2018.

Kubica, who hasn't raced in Formula One since suffering life threatening injuries in a 2011 rally crash, is favourite to take the seat left vacant by the retiring Felipe Massa. The Polish driver impressed Williams in tests of a modified 2014 car at Silverstone and the Hungaroring earlier this year, but this is the team's first chance to assess his capabilities in the modern generation of F1 car.

Speculation of a return to F1 has been rife all year, with several private tests for Renault leading to a day in the car at the post-Hungarian…