Sebastien Buemi has been earmarked to replace the departed Sebastian Vettel at Toro Rosso, says Dietrich Mateschitz.

The Formula One team’s owner revealed this on Monday to quell some of the rumours surrouding the identity of Vettel's replacement.

”One will very likely be Buemi,” Mateschitz told the autosport.com website. “The line-up will be confirmed before the last test in December.”

The 20-year-old Swiss is their test and reserve driver for the 2008 season. Buemi also drove the medical car during the Japanese F1 race this season because one of the drivers had an ear problem.

Vettel had joined the main Red Bull Racing team to replace the retired David Coulthard.

According to reports, Sebastien Bourdais has also yet to be confirmed for 2009, leaving another possible vacancy.