Mark Webber will not take part in Formula 1's 'young driver' test at Silverstone after Red Bull made a late change to its planned schedule.
The Australian, who will leave the team to drive for Porsche in the World Endurance Championship at the end of the season, had been due to test on Thursday afternoon.
Race drivers have been allowed to join this year's test in order to work on Pirelli's new tyres, but AUTOSPORT understands they must run to a strictly-defined Pirelli programme that covers two half-days of running.
With Red Bull keen to evaluate Daniel Ricciardo, and with Sebastian Vettel set to come in on Friday afternoon, Red Bull has therefore reshuffled its plans.
Ricciardo, known to be highly-rated by the Red Bull crew that ran him in the 2009 and '10 young driver tests, will now test on Thursday afternoon.
His performance could be decisive in whether he lands a race seat for next year.
Antonio Felix da Costa, originally scheduled to hand over to Ricciardo for the afternoon, will now test for the entirety of Wednesday and again on Thursday morning, before Ricciardo assumes control.
Carlos Sainz Jr will then test early on Friday, with Vettel replacing him for the afternoon.
Ricciardo will also test for Toro Rosso on Thursday morning, immediately before switching to the RB9.
Lotus has announced that Kimi Raikkonen will not be running at Silverstone this week as the restrictions on the amount race drivers can do at the test make it more beneficial to leave test driver Nicolas Prost in the car for another day instead.
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