“We had our problem at Assen with the tyre, which was not Yamaha's fault, and also at Silverstone. But at Qatar and here and Laguna, we've had three mechanical problems with the bike. I wouldn't say it's Yamaha's fault at all. It's just been bad luck, too.
“Why it's happening to me, I don't know. There was a big frustration level, I'd say, about a month ago. But now it's just... we go to Brno, and I just kind of wonder what's going to happen next."
Spies, who is just tenth in the championship with a best finish of fourth this year, will be replaced by Valentino Rossi next season. The former World Superbike champion, with Yamaha, is yet to announce his 2013 plans.
Team-mate Jorge Lorenzo leads the championship and finished second at Indianapolis after Spies' smokey exit.