The motocross season opens Saturday in San Bernardino, but off-road motorcycle racing's biggest star, Ryan Villopoto, will be on the sidelines.
The Red Bull Glen Helen National, at Glen Helen Raceway, is the opening event of the 12-round Lucas Oil Pro Motocross Championship series that ends Aug. 23 with the Utah National.
Villopoto, the defending motocross series champion, announced this month that he would miss the season because he's having surgery on his left knee.
That leaves other top riders including Ryan Dungey, James Stewart, Chad Reed and Justin Barcia vying for this year's series championship.
The 25-year-old Villopoto this spring also won his fourth consecutive title in supercross, the stadium version of motocross.