LOS ANGELES -- With two-time champions James Stewart and Chad Reed sidelined with injuries, rookie Ryan Dungey won the nation's top-tier supercross championship last year.
But Stewart and Reed are back as the new season opens Saturday night in Anaheim, and the challenge for Dungey and other riders to stay up front is again much tougher.
The Monster Energy AMA Supercross Series kicks off its 17-race schedule at Angel Stadium, and three of its first five races are in Southern California.
But whereas the series used to race at Angel Stadium three times early in the season, this year it will visit Anaheim twice while also making its debut at Dodger Stadium in Los Angeles on Jan. 22. The second Angel Stadium race is Feb. 5.
Supercross, which features the riders making high-flying leaps from specially designed mounds of dirt as they speed around the track, is the stadium version of motocross, or off-road motorcycle racing.
Reed, a 28-year-old Australian who won the supercross title in 2004 and 2008, suffered a season-ending broken left hand last year in a crash with Stewart during the second race, in Phoenix.
A week later, Stewart, the 2007 and 2009 champion, pulled out for the season when it was discovered he had suffered a broken bone in his right wrist in the Phoenix crash and required surgery.
That opened the door for Dungey, 21, to win six races and the championship on his Suzuki over series runner-up Kevin Windham and David Millsaps, who finished third in the point standings. Dungey became only the second rookie to win the title; the other was legendary supercross rider Jeremy McGrath.
After the supercross season ended in May and the riders switched to motocross racing, Dungey also captured the AMA Motocross championship in the second half of the year.
Dungey on Thursday said his supercross title wasn't diluted because Stewart and Reed were on the sideline.
"A championship is a championship," Dungey said. "Now, 2011, it's a new season. We'll have everybody there and you'll have no excuses."
Stewart agreed, saying Dungey was "deserving" of the title. "I'd take it his way (with some rivals injured) if I can get it."
Reed and Stewart, 25, aren't the only riders rebounding from injuries that prematurely ended their seasons last year.
Kawasaki rider Ryan Villopoto, 22, won seven times in 11 races in 2010 -- and was battling Dungey for the title -- until Villopoto broke his right leg in St. Louis.
And Honda rider Josh Grant, 24, sustained a shoulder injury in a practice crash before last year's first Anaheim race, ending his season as well. Grant won the season-opening race in Anaheim in 2009.