Felipe Nasr is set to be announced as Williams' next reserve driver.
Emerson Fittipaldi: "I don't believe we (Brazil) will have no drivers in Formula One next year"
Definitely not too young is Felipe Massa, the highly experienced Brazilian driver who could be looking for a 2014 seat after eight years with Ferrari.
Tost said on Wednesday the Faenza based team is not ready to name Ricciardo's successor.
Felipe Nasr may be in the running for the supposed vacant seat at Toro Rosso next year.
Stefano Coletti is the classification leader with 135 points, followed by Nasr at 108 and Bird at 90.