Four-time world champion Sebastian Vettel is leaving Red Bull at the end of the season and is set to join Ferrari, the Formula One team said.

Red Bull said in a statement Vettel's seat would be taken by 20-year-old Russian driver Daniil Kvyat, while team boss Christian Horner said at the Japanese Grand Prix on Saturday the German would be racing for Ferrari from next season.

We also look to the future with excitement, as the vacancy makes way for the next generation of Red Bull racers

Red Bull

Vettel's departure may trigger a merry-go-round of team switches, with Fernando Alonso's future at Ferrari a hot topic of paddock discussion.

Alonso's contract runs until the end of the 2016 season but the 33-year-old Spaniard has been linked heavily with a move to former outfit McLaren.

"Sebastian Vettel has advised us that he will be leaving Red Bull at the end of the 2014 season," Red Bull said in a statement. "We want to warmly thank Sebastian for the incredible role he has played at Red Bull for the last six years.

"As we wish Sebastian well in the next stage of his career, we also look to the future with excitement, as the vacancy makes way for the next generation of Red Bull racers," the team added.

Red Bull boss Horner told Sky Sports that Vettel informed him of his decision on Friday.

Ferrari had not made any announcement on Saturday about their future line-up.

Vettel has struggled to recapture championship form this year following the implementation of new technical regulations for the sport, and has yet to win a race.

He is fifth in the championship standings, with teammate Daniel Ricciardo third behind the Mercedes pair of Lewis Hamilton and Nico Rosberg.

Source: Reuters