Valentino Rossi has spoken of his intense disappointment at being unable to succeed in MotoGP with Ducati.
The seven time MotoGP champion will return to Yamaha next season, after claiming just two podiums in 27 races on the Desmosedici.
Official statements confirming his Ducati departure and new two-year Yamaha deal contained no comments from Rossi.
The Doctor then sent a series of Tweets expressing his regret at not being competitive on the Ducati, but Thursday at Indianapolis marked the first time the 33-year-old had spoken in public.
“After Laguna and the summer break, I have enough time for to think more deeply to my future,” began Rossi. “You know, this is a great pity for me and Ducati and for all of our fans, but especially for all the guys that work with me at this project because I want to try to be competitive.
“Italian rider with Italian bike, but unfortunately, it doesn't happen. These two seasons are very difficult, and we are struggling very much. Unfortunately, we were not able to improve our speed, our performance, and to fight for the good position, for the front position.
“So I decide for these reasons that it is enough and my choice is [Yamaha] because I try to understand which is the best bike, the more competitive bike for the next two years that maybe at the end of my career, or anyway the last part, and this is the choice.
“It's a great pity. I'm very sad, also, because in Ducati I found a lot of good people. We had great times together. We try the maximum, but unfortunately we were not able to achieve the result. So this is what makes the difference.”
Asked if his time at Ducati had been a humbling experience, Rossi replied: “I cannot say no. I mean, you can use which word you prefer. It was very, very difficult. It's not true that we don't try, we try the maximum. But I was never able to be fast with the Ducati, and this is a great, great pity, a very bad thing, especially for me and for my team.”
Rossi rejected an imaginative suggestion that some of his Ducati difficulties were somehow caused by a lack of technical development by former rider - and Ducati's only world champion - Casey Stoner.
“I never say this,” declared Rossi.
Instead, Rossi indicated that the only 'problem' Stoner had caused was to make the Desmosedici seem better than it actually was.