Casey Stoner has expressed his gratitude to Ducati following the announcement that he will leave the manufacturer after four years in favour of a switch to rivals Honda.

Following weeks of rumours, both Ducati and Honda submitted announcements to confirm Stoner's impending switch at the conclusion of the season, the Australian all set now to bring his tenure at the Italian manufacturer to an end at Valencia Grand Prix in November.

Stoner is currently in his fourth year with the manufacturer, during which time he made history by becoming the first champion of the 800cc era, while his 'vital statistics' have seen him win 20 premier class races during that period.

Even so, Stoner has been unable to match his performance on the Desmosedici since winning in 2007, the Australian losing out to Valentino Rossi in 2008 before illness curtailed his title hopes last season. This year, Stoner has managed just two podiums in seven races.

Citing a 'new challenge' as his reason to join Honda, Stoner nevertheless gave Ducati thanks for giving him the chance to become a world champion.

"I must thank Ducati for giving me such a great opportunity to race and win with them over these past four years." he said. "They took a gamble when they signed me at the end of 2006 as I was unknown, but as we worked together we were able to win a Championship, many races and challenge for the Championship in the last two seasons.

"I have now decided to move on and I will have new challenges in the future and different obstacles to overcome, but I will not forget these years with Ducati and the people I have had the privilege to work so closely with. So a big thanks to Ducati and all our sponsors who we have shared success with while achieving lifelong goals."

Stoner's sentiments are echoed by Ducati Corse general director Filippo Preziosi, who also leant his thanks to the rider for winning its first title.

"I would like to thank Casey on behalf of our fans and our sponsors, but most of all on behalf of all the people working at Ducati. The victories and emotions he gave us, rewarded all the hard work and sacrifice we made. In these four years together we have had a lot of great moments.

"Securing the 2007 MotoGP World Championship title and the victory at Mugello in 2009 were moments that we will never forget. In Casey we not only found an incredibly talented rider, but also an honest and loyal guy and that's why there will always be a strong and sincere bond between us, even as a competitor."