Villopoto said in a statement on Thursday that he is still in severe discomfort after a crash in Italy this April left him with multiple tailbone fractures and compressed disks in his lower back.
The 26-year-old rider from Fortuna, California, joined Jeremy McGrath as the only riders to win four straight Supercross titles with his victory in 2014 before leaving to race in Europe.
He also won outdoor motocross titles in 2011 and 2013 and is fourth all-time with 83 combined victories in the two series.
Villopoto also won all four of his races for Team USA in Motocross of Nations competition.
Villopoto's statement:
It is with gratitude, humility, a bit of sadness but without regret, that I announce my retirement from motorcycle racing today.
As many of you know, I experienced a pretty horrendous crash back in April that left me with multiple fractures in my tailbone along with soft tissue damage.
My initial thought was that I could be back riding in a few weeks if I just stayed quiet for a while.
That has not proven to be the case.
Follow-up X-Rays have made clear that I also suffered severe compression of multiple disks in my lower back.
I am still in significant discomfort and I realize that even if I start my fitness program and training now that I been cleared by my physician, I will not be able, prior to the end of the MXGP season, to achieve the fitness necessary for me to compete at the level I have always striven for.
I am grateful for having had the opportunity to do something I have loved since I was a kid and turn it into my livelihood.
I am grateful for the support of my family for all the years they spent hauling my bikes and me around to races, interrupting their lives in the process.
I am grateful for the support of my many sponsors through the years.
What people don’t often think about, when it comes to individual “action” sports like motocross, is that we rely on sponsors to compete.
In motocross, the sponsors aren’t just a name on your jersey – they are part of your racing team.
If they are good, they are sponsors in the truest sense of the word.
They are involved in building the best bike, putting together the best team, supporting your training, and so much more.
So, with that in mind, first and foremost I want to thank Kawasaki, which has been my bike of choice since my Team Green days.
They have been with me through ups and downs, serious injuries and great successes.
They’ve always cared about me and I’ve been successful in large part because of it.
THOR/Parts Unlimited and Monster Energy Company have been with me through it all as well.
Thanks also to DC, GoPro, Oakley, Alpinestars, Atlas and Mobius Braces.
Each of you has been an integral part of making this an amazing career.
I want to thank my long-time agent, my friend, Bobby Nichols, and his agency The Sports Syndicate, for the strong guidance and support they have offered my entire career.
But most of all, I’m writing this retirement note to my fans.
I am grateful for the hundreds of thousands of fans, not only in the U.S., but throughout the world.
It is amazing to know that you have cared so much and been so supportive along the way.
That gets me to the sadness about making this decision now.
I was so stoked to make the decision to be a part of MXGP racing.
It has always been important to me to ride my best and to be in the best possible position to give my best, in part because of wanting to give back to you, the fans.
I am sad that this year did not work out the way I had hoped in that regard.
I wanted to be at my best, to compete with these riders who are among the very best in the world and leave it all out on the track as each of them does every race.
The sadness is that I only got to do that for a few races.
I am grateful to have had the chance to race with the very best in world, my competitors in Supercross and Motocross in the States as well as those who make the MXGP what it is.
I am grateful to know that our competitiveness helped to continue the growth of our sport.
I leave with no regrets.
I have been blessed to experience so much of life through my racing.
I have never wanted to disappoint my fans nor my supporters and my hope is that for the most part I have lived up to that.
Again, thanks to each and every one of you who have been a part of my team.
Sincerely,
Ryan Villopoto