Monster Energy Kawasaki’s Ryan Villopoto will not defend his AMA Motocross title in 2012 after injuring his knee at the Seattle supercross on Saturday night. The two-time AMA Supercross and defending AMA Motocross champion will undergo surgery on his knee this week.

“I’m pretty disappointed right now,” said Villopoto. “I have trained hard for this season and even though I won the supercross title, I really wanted to defend my outdoor championship. I’ve been through injury before and I know how hard I have to work to get back.”

Villopoto is coming off of a dominant 16 months where the Poulsbo, Wash., native earned two AMA Supercross titles on the strength of 15 wins, the AMA Motocross Championship with three wins and also the richest payday in supercross with a million dollar win at the Monster Energy Cup.