Global Motorsport Media
Even Toro Rosso's team boss insists he doesn't know who will be in the race cockpits next year.
He told Marca sports newspaper that the decision will be referred to team owner Red Bull's Salzburg headquarters.
"Right now nothing is decided," he said, amid rumours Sebastien Buemi and Jaime Alguersuari might be ousted to make way to newcomers Daniel Ricciardo and Jean-Eric Vergne.
"When this race is finished it will go to Salzburg for a detailed analysis of what the drivers have done. They will decide what is best for the team," said Tost in Brazil.
The Austrian however said he has been satisfied overall with Buemi and Alguersuari in 2011.
"When the car was good, they have had a good performance. Yes, in that way we're happy," said Tost.
Swiss Buemi, however, is the more experienced of the pair but he has scored fewer points, even though he has had the lion's share of the technical problems recently.
"Jaime has had two or three really good races, really good," said Tost.
When the car was good, they have had a good performance
But he refused to estimate the chances that he might be working with a new driver in 2012, or possibly Australian Ricciardo as well as Frenchman Vergne.
"There is always the possibility," said Tost. "Nothing is ruled out at this time."