Irvine, Calif., -- Monster Energy Kawasaki’s Ryan Villopoto will be unable to defend his 2013 AMA Pro Motocross Championship title after opting to get knee surgery to fix a lingering injury. Villopoto battled with the knee issue throughout the Monster Energy Supercross season, and after consulting his medical team, it was decided he will undergo surgery on his knee as soon as possible. Monster Energy Kawasaki has signed the 2013 Canadian Monster Energy Motocross Nationals Champion Brett Metcalfe to join Jake Weimer for the 2014 AMA Pro Motocross season.

“This is definitely not the news I wanted to hear from the doctors,” said Villopoto. “We have worked hard to be in position to win championships for Monster Energy Kawasaki and to not be able to race this summer is very disappointing. Going from a really great feeling after winning a fourth straight supercross title, to knowing I am going to spend the summer rehabbing a knee injury is devastating.”

“Obviously this is a big blow for the Monster Energy Kawasaki team,” said Kawasaki Senior Manager of Racing Reid Nordin. “Even with the injury Ryan has shown he is the top rider in our sport, but we are listening to his medical team to make sure he gets his knee fixed properly and he can compete for championships in 2015.”

Villopoto is coming off of a dominant Monster Energy Supercross season where the Poulsbo, Wash. native joined “The King of Supercross” Jeremy McGrath as only the second rider to ever win four consecutive supercross championships.