The latter has been part of Red Bull's developing programme for quite some time now and has tested for Red Bull Racing throughout the 2007 season. He also managed to finish the 2008 GP2 Main Series in 6th place (while driving for Trust Team Arden) on his first appearance in the championship.
As for Bourdais, the 4-time ChampCar Series champion was already assured by manager Nicolas Todt that he would be continuing with the Scuderia for at least one more season. However, with the team's officials yet to make a decision on next year's lineup, one could not take anything for granted. Especially Bourdais who, using the same machine as teammate Sebastien Vettel, only managed to score 4 points in 18 races.
The Frenchman started off great in the 2008 season, scoring an impressive 7th place in Australia. However, Bourdais failed to keep up the momentum and didn't put any more points on the scoreboard for the following 11 races. Another 2 points in Belgium lifted Bourdais' morale for the closing stages of the 2008 season, leading to some impressive performances in the last few races.
While running into 6th place during the Japanese Grand Prix, the Frenchman was handed a penalty after a racing incident with Felipe Massa and was demoted by the race officials all the way onto 10th place. Nevertheless, his run at Mount Fuji was recorded by Gerhard Berger and will probably help him this winter.
Sato, who began the 2008 season as a Super Aguri driver but ended his run in the championship after his team retired due to financial problems, has already tested for Toro Rosso earlier this year. Bruno Senna is also in contention for a racing seat with STR, despite testing for Honda next week.