EUGENE, Ore. —Tyson Gay accelerated through the first curve. Then, he started flying.

Not in the figurative sense, but in an all-too-real way — a shocking sprawl to the ground that cost America's best sprinter an Olympic spot in the 200 meters and made him look like less than a sure thing, health-wise at least, with the Beijing Games five weeks away.

Gay suffered what his manager called a severe cramp in his left hamstring at the U.S. Olympic track and field trials today and had to be carted off the track. He was at his hotel later, being treated with ice.

"It was just one of those things," Gay said in a statement released through USA Track and Field.

Gay already has qualified for the Olympics in the 100 meters, but his chances at doubling are gone. Now, the nervous wait begins to see if it was, indeed, just a cramp, and how that affects his training over the next month.

"There is no apparent damage otherwise, except for some road rash from the fall," said Gay's manager, Mark Wetmore. "He said he felt a little tightness before the race."

Wetmore said Gay was getting an MRI as a precaution. Results were not immediately available.

"When he wakes up tomorrow, he'll know," said former decathlete Dan O'Brien, who famously missed the Olympics 16 years ago. "He'll be able to stretch it out, he'll be able to move it. If he can't sit on the toilet tomorrow, he's got problems."

Had this been gymnastics, or a number of other sports, an injury at trials wouldn't have ended Gay's chance to make the Olympics in that specific event. But USA Track and Field plays it straight — top three finishers at trials make the Olympics, no exceptions.

It's a black-and-white policy that most athletes accept, though it could end up costing the American team as much as Gay in Beijing. Gay is the defending world champion in the 100 and 200 meters.

"I don't know any other way to do it, but it's tough," said Wallace Spearmon, now the favorite in Sunday's finals. "Either you're ready on this day or not. You can be the best athlete coming into it, and you could be sitting at home watching it from the house."

It was, in fact, a stunning setback for the 25-year-old Gay who last week set the American record in the 100 at 9.77 seconds. In the final, he ran it in 9.68, the fastest time ever recorded, but not a world record because the tailwind was too strong.

"It's scary. Especially in a round," said 200 women's favorite Allyson Felix. "It kind of shakes up your nerves. But you can't really do anything about it."

Damein White, running in the lane next to Gay, said he saw Gay pull up and saw something fly his way. It was the white sticker with Gay's number on it.

"I tried to keep going off the curve," White said. "It kind of threw me off. He just pulled something. He'll be right back. Next year, we've got worlds. You'll see him there."

More urgently, however, are the Olympics. Qualifying for the 100-meter dash starts Aug. 15, and Gay was one of the favorites, along with world-record holder Usain Bolt and Asafa Powell, both of Jamaica.

Members of the U.S. track team are expected to leave for the games about 10 to 14 days before their event starts. Gay also was committed for a meet in London on July 25 and was considering running in a couple more events in Europe before the Olympics.

The injury will open up another spot in the 200, where Gay, Spearmon, Xavier Carter, defending Olympic champion Shawn Crawford and Walter Dix were considered among the top runners going for only three spots.

"It doesn't really change things on my part," Carter said. "Tyson's a great runner. He's No. 1. Everybody was shooting for him. I'm not going to change anything because he got hurt. I've got to continue doing what I was doing as if he wasn't hurt."

There were no more surprises in the 200 semifinals later Saturday, when all the top contenders advanced. Same in the women's heats, where Felix, 100 champion Muna Lee, Lauryn Williams and Torri Edwards all made it to Sunday's finals without much drama.

Gay's injury, however, made the day a little difficult for everyone involved.

"It's such an awful thing when bad things happen to good people," Williams said.

If his injury truly was only a cramp, he could be back on the track soon.

If it's more serious, it would be a blow for track, at least on the American scene.

Gay is considered one of the fresh, young faces of a sport that has endured unrelenting doping problems over the past several years. Many were hoping to turn the page this season, and they were hoping Gay, a bit shy, but successful, would be a big part of that.

"I'm really glad they're saying it's just a cramp as opposed to what it looked like," Williams said. "My eyes started to well up, like please, 'God no, don't take him away from us now.' The USA needs him."