Red Bull, Toro Rosso, Ferrari and Mercedes - are travelling to Bahrain with their 2013 cars to help Pirelli develop 2014's tyres.
Dec.12 (GMM) World champion Sebastian Vettel, and 2013 runner-up Fernando Alonso, will not be testing tyres for Pirelli next week in Bahrain.
"Sebastian is currently on vacation," Red Bull driver Vettel's spokeswoman Britta Roeske told the Welt newspaper.
"Sebastian will reflect on the past season and prepare for the new one, but that is nothing different than what he has done in previous years.
"He will only reappear in public if there is an official Red Bull appointment, or at the first (official) tests" in late January, she added.
Similarly, Ferrari's Alonso will also not be in Bahrain, with the Italian team confirming that Pedro de la Rosa and Jules Bianchi will do the tyre work instead.
And a report by Speed Week said that while Mercedes' Bahrain lineup is unclear, 2014 racers Jean-Eric Vergne and Daniil Kvyat will be in action for Toro Rosso.