South Australian Brett Metcalfe will replace Ryan Villopoto at Monster Energy Kawasaki in the 2014 Lucas Oil Pro Motocross Championship, it was announced this morning in the US.

Villopoto, fresh from capturing a fourth straight Monster Energy Supercross title, will undergo knee surgery following ongoing complications with the injury during his supercross title defence.

“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.”

It’s been widely speculated that the current outdoor champion will retire following this season, however Kawasaki senior manager of racing Reid Nordin is expecting Villopoto to return for 2015.

“Obviously this is a big blow for the Monster Energy Kawasaki team,” said 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.”

Metcalfe, who turns 30 today, won the 2013 Canadian Motocross Championship on debut last year for Leading Edge Kawasaki, initially slated to return north for the season until the opportunity to fill in for Villopoto arose.

During his career Metcalfe’s best finishing 450 Class championship position was second in 2010 and fourth in 2011. He’s also finished top five in the 250 Class three times, including third in both 2008 and 2009.

Metcalfe’s lone overall victory came in the 450 Class at Southwick in 2011. Last season he contested a selection of one-off races, finishing fourth at Southwick, seventh at Unadilla and eighth at Lake Elsinore.

Meanwhile, Josh Hill will replace Metcalfe in the Canadian championship for Leading Edge Kawasaki after he was replaced by Weston Peick at RCH Racing Suzuki in the US for the motocross season.