This week, Red Bull confirmed Sebastien Buemi would be retained as the reserve driver for an eighth consecutive season in 2019.

It is a position he has held ever since he was dropped by Toro Rosso at the end of 2011, with this year marking a decade since the Swiss driver made his debut with the junior team.

That hasn't stopped Buemi from carving a successful motorsport career elsewhere with championships both in the WEC and Formula E, and that meant he was thought to be an option for a Toro Rosso comeback this season.

However, as it turned down, those achievements may have worked against him.

"He earns very, very good money in Formula E," Red Bull advisor Helmut Marko told Motorsport-Total.

"He's in a happy environment. We could not offer him the same salary he earns in Formula E and the World Endurance Championship at Toro Rosso."

Instead, the Italian team will feature another former driver in Daniil Kvyat alongside F2 graduate Alexander Albon in an all-new line-up.