Team boss Franz Tost has confirmed that the Toro Rosso's 2012 drivers will be selected from the pool of Red Bull drivers.

Both Sebastien Buemi and Jaime Alguersuari are seeking to retain their drives for next season, with the latter doing his chances no harm at all with three top eight finishes in the last five races.

However, the pair are under increasing pressure with Toro Rosso test driver Daniel Ricciardo having been placed in a race seat with HRT to gain extra experience, and World Series by Renault runner-up Jean-Eric Vergne being handed the chance to take part in Friday practice at three of the final four events of 2011.

Those four are the most likely candidates to fill the Toro Rosso seats next season, and Tost confirmed that the team wasn't looking outside the Red Bull stable when it came to its drivers.

"It is 100 per cent certain that next year we will have two Red Bull drivers," he was quoted as telling Sportwoche. "That is the meaning and the purpose of why Red Bull bought the team.

"Our job is to allow young drivers from the Red Bull pool to enter formula one in training for Red Bull Racing."

However, despite Toro Rosso being purchased to give Red Bull chance to help develop its young drivers, only Sebastian Vettel has made the move into the main team and Tost said it was easy to see why the German had been the one to break through.

"The reasons for that are simple," he said. "First, he is more talented than the others. He is also more disciplined, brings more passion for the sport, is more innovative, open and more flexible in accepting suggestions to make himself better. That's why he's the world champion."