Reigning MotoGP champion Casey Stoner is just 26 years old, but has been riding in the FIM series since 2001 when he joined the 125cc ranks. Five years later, the Australian was in the headlining formula series with Honda, the year after that, in 2007, he won the title astride a Ducati. Last year, Stoner won it again with Honda, and even battling an issue with his arm this year, he's atop the standings and leading his rivals in practice sessions for this weekend's French GP at Le Mans.

But Stoner used yesterday's GP press conference to announce his retirement at the end of this year. The Australian says the sport had gone in a direction that doesn't interest him and that he simply isn't enjoying it enough to continue the sacrifices necessary to be competitive at the top level. Speculation is that he wants to spend time with his wife and daughter, and perhaps that he plans to drive in the Australian V8 Supercar series.

Fellow Aussie and MotoGP legen Mick Doohan said he doesn't believe just yet that Stoner will actually ride off into farm life. Even so, the fact that the current World Champion is unhappy enough to publicly announce the end of his career is a shock to the MotoGP world. Have a look below for a video news report on Stoner's announcement.