Yamaha's David Philippaerts has been ruled out of the MXoN for 2010 with a knee injury.

Yamaha Monster Energy Motocross Team’s David Philippaerts is unable to contest the 64th Motocross of Nations for Italy at Thunder Valley in the United States on 26 September after suffering a second-degree strain of the media lateral ligament in his right knee.

In another late development less than two weeks before the meeting teammate Gautier Paulin will represent France in the MX1 category with a works YZ450FM and is currently testing in Italy.

Philippaerts had been called up for selection last Saturday at Fermo during his home Grand Prix to turn-out for his country for the sixth time at the biggest event of the season but upon entering a hard rut at speed in the second moto twisted his right leg.

Philippaerts was able to complete the race and confirm his third position in the FIM MX1 World Championship on the factory YZ450FM but went immediately back to his home north of Milan for a medical opinion.

A scan yesterday revealed the damage that will not require an operation but needs the 2008 world champion to rest for a period of twenty days before he can then begin light cycling and running with a view towards improved fitness for the team’s planned off-season testing schedule.

“This is the last thing I wanted to happen because the news at Fermo that we could go and race for our country was fantastic for us and all the fans,” he said. “I’m lucky that the injury is not a third-degree tear because that would mean surgery.

“However I cannot ride nor do anything for nearly three weeks now; if the ligament has any more stress then it might go completely and that would put me out for quite a while.

“I want to thank all the people that supported me at the weekend and through the season and I am sorry I cannot do the Nations for them, the team and all our sponsors. I really hope that Italy can do well.”

Meanwhile, after a successful second half of the 2010 MX2 campaign with victory for the YZ250FM in Holland and four podium results from the final five rounds Gautier Paulin is now ready to try and repeat his 2009 Nations race win on the larger machine for France.

The 20-year-old was called into the French line-up after a shoulder injury to Christophe Pourcel and now has only few days to get his YZ450FM dialled-in before flying across the Atlantic for the third time this year.

“While I am sorry for Christophe this is exciting news for me and I am proud to represent France as part of a strong team,” said ‘21’ who was one of the most exciting stars of the 2009 edition at Franciacorta. “There is not much time to prepare but we are working hard now to get ready on the bike and be as fast as possible for Thunder Valley.”

Pourcel was injured in last weekend’s final round of the AMA Motocross Championship, eventually losing the title to Honda’s Troy Canard.

The Motocross of Nations will see over 30 countries field their three fastest riders in a three moto contest. The historic event has been won by the Americans for the last six editions with France runners-up for the last three.