Vettel replaces injured Coulthard in test.

Sebastian Vettel has been parachuted into Red Bull Racing's RB4 for today's testing in Barcelona, after regular pilot David Coulthard was forced to sit out proceedings.

The Scot pulled out of the second day of the three-day test at the Circuit de Catalunya after tweaking a neck muscle on day one. He is now undergoing treatment to the injury in a bid to be fit in time for the final day - the last opportunity for Formula 1 teams to take to the track before the season-opening Australian Grand Prix in under three weeks' time.

The 36-year-old has been replaced for the day by Vettel, who will race for RBR's sister outfit Scuderia Toro Rosso during the 2008 F1 campaign, The young German was available as STR are only running one car on Tuesday, which will now be driven solely by multiple Champ Car title-winner S?bastien Bourdais.

Coulthard wound up bottom of the timesheets after completing just 25 laps' running on the opening day in Barcelona, with the adverse weather conditions and technical issues as well as his neck conspiring to blunt his efforts. The RB4 has generally demonstrated encouraging pace during pre-season testing so far, but team-mate Mark Webber was still only tenth-quickest on Monday, just over eight tenths of a second shy of McLaren-Mercedes pace-setter Lewis Hamilton.

According to the BBC, a Red Bull spokesperson confirmed that Coulthard's injury is not serious, but added that he did not wish to further aggravate it ahead of Melbourne.