Nico Rosberg joined the team in Barcelona today for day three of this week's four day test, the first of 2009 involving all ten teams which will line up for this year's Formula One World Championship.
With the season kicking off in just under three week's time, the team are using the week to test reliability, carry out systems checks and continue with an extensive programme of set-up work.
On his first day back in the cockpit, Nico completed 89 laps of the Circuit de Catalunya's 4.655km track, a total of 414kms, and set the seventh fastest time of the session with a 1:21.324.
Dickie Stanford, Test Team Manager, Williams F1: "Nico Rosberg took over from Kazuki today and carried on with our programme of set-up and development work on the FW31. He'll stay in the car tomorrow for our last day in Barcelona."