LONDON, England - Brazilian Felipe Nasr's uncle/manager insists his charge is the "real third driver" for Williams this year - not Susie Wolff.The comments made on February 21 by Amir Nasr, a well-known figure in Brazilian motor racing, followed news that Susie Wolff would drive the new Williams at the British and German Formula 1 GP's in 2014.Just days earlier the UK-based team appointed the Bank of Brazil-backed 21-year-old Nasr to the test and reserve roles, saying he was to appear in the Mercedes-powered FW36 on five Friday mornings through 2014.SHARED OR BACK-SEAT DRIVER?Speaking to Jovem Pan radio in Sao Paulo, Amir Nasr played down suggestions Felipe's new role could be a shared or back-seat one, such as when Lotus reserve Davide Valsecchi in 2013 was overlooked when Kimi Raikkonen headed for back surgery.Amir Nasr said: "Felipe is the real third driver of the team - it is in the contract. In case of any problem with the race drivers, he is the natural replacement. He will have to go to all the F1 GP's and will work in the simulator to compensate for the lack of track time. It is a more complex task than it seems."Amir Nasr said only a one-year contract with Williams was agreed because the British team could not confirm a race seat for 2015.He added: "Williams has two very good (race) drivers. Massa has a three-year contract while Bottas is 23 and a potential World champion. We could not agree a longer contract because we would not have a guarantee he would be promoted."