EUGENE, Ore. — Olympic decathlon champion Bryan Clay of Hawai‘i withdrew from the U.S. national track championships today with an injured left hamstring, a decision that could force him to shut down his entire 2009 season.

Clay, who hurt himself Tuesday in workouts, warmed up briefly before the meet started, but decided he couldn't compete.

Because of that, the Castle High alum from Kane'ohe can't qualify for world championships, to be held in Berlin later this summer. Only the top three finishers this week at nationals receive bids, and Clay's Olympic gold medal doesn't earn him a wild card spot.

"I've got to sit down with my coaches, my agents and weigh the options," said Clay, who will spend the rest of the week tweeting about nationals. "I've got to see where we're at, see what meets are out there. I honestly don't even know where to begin for that."

Clay said the injury would probably be healed in six or seven days. But he was still within 48 hours of hurting it, and extensive time in therapy over the last two days wasn't enough to get him in competition form.

"If I could go out there and run a 10.8, I'd run a 10.8" seconds in the first event, the 100, Clay said. "But there's no way I can run a 10.8 today, so we shut it down. There's no use in me going out there, running an 11.5, risking further injury and maybe not be able to finish anyway."

The decision to withdraw not only hurts Clay, it also deprives the sport of one of its biggest stars in a marquee event. And it brings one of track's strange rules back to the fore. Titlists from the last world championship, in 2007, receive automatic bids into the 2009 championships but 2008 Olympic champions do not.

Meanwhile, American rules call for the top three finishers — along with defending world champions — to earn spots at worlds, with no exceptions for injuries.

That has led to a strange program this week, with runners like Tyson Gay, Jeremy Wariner and Bernard Lagat, none of whom won Olympic gold, able to skip marquee races because of their 2007 titles while Clay gets no such break.

"The rule doesn't bother me at all," Clay said. "I just wish the Olympic champions were included in on that rule for the year after the Olympics. I can honestly say if that rule was the same for Olympic champions, I know in my heart I'd be going to world championships ready to compete for a medal in six weeks."

Instead, he'll miss the national championships for the first time since he turned pro in 2001.

Clay conceded he's worried that some people will criticize him for being too injury prone. Had he not pulled out of those 2007 worlds with a leg injury when he was in second place, he might have an automatic trip to the 2009 worlds already sewn up. He also pulled out of nationals in 2006 (low blood sugar) and 2007 (leg).

He said this setback doesn't change his long-term plans. He's still shooting to break Roman Sebrle's world record (9026 points) and wants to make the 2012 Olympics, where he'll try to become the first decathlete to win medals in three straight games.

"I'd hope that my actions speak louder than words, that's all," Clay said. "I hate disappointing people. I wanted to go out there and put on a good show. I don't want there to be any question about where I'm headed in the future."