CLEMSON — Hopping aboard a friend's scooter for a joy ride isn't one of the dangers Chris Hairston was warned about when he arrived at college.

Yet Hairston can provide a first-hand account of how something so simple and harmless can go so wrong.

An injured knee suffered Sept. 6 in a scooter accident cost Hairston almost all of the past three games. And it came close to costing him a game he cannot bear to miss — Thursday night's tilt against his hometown team, Wake Forest.

"It was a bad decision, really," said Hairston, a third-year sophomore who's expected to start at left tackle when Clemson takes the field against the No. 21 Demon Deacons in Winston-Salem, N.C.

"I've gained a little bit of wisdom from the situation. I've learned you can't put yourself in bad situations, especially when you've got a team counting on you."

Hairston's recollection of the fateful night goes like this: He was off- campus at a friend's apartment relaxing a few hours after a 45-17 win over The Citadel. He decided he wanted to take his friend's scooter for a spin.

Hairston, all 6-6 and 315-pounds of him, hopped on and pulled away. Before long, he was thrown to the ground after the scooter hit a sewer grate and went flying.

"He's just really goofy," said tight end Michael Palmer. "When you hear Hairston fell on a moped, your first reaction is, 'What the heck?' "

This tumble inflicted a severe toll: a ruptured bursa sac in Hairston's left knee. It was initially thought to be a minor injury, but team doctors had difficulty draining the abundance of fluid that had accumulated.

He missed the South Carolina State game. Then the North Carolina State game. Not good news for an offensive line already struggling with youth, inexperience and other injuries.

Hairston was the team's best pass protector, and maybe its best lineman. His absence was Brad Scott's worst nightmare.

"It'll be a long time before he'll live that down, I'm sure," said Scott, the Tigers' offensive line coach.

Hairston considered himself lucky to be at Clemson to begin with. He was a late bloomer at Carver High in Winston-Salem after arriving at the school as a 175-pound freshman. He took up football and drew little notice until his senior season, when he was selected for the Shrine Bowl.

South Carolina State was courting him heavily, and Hairston said Bulldogs assistant Joe Blackwell - brother of Clemson linebackers coach David Blackwell - let Tigers coaches know about Hairston.

Former Clemson assistant Marion Hobby began recruiting him, and Scott liked what he saw after looking at his film.

Hairston was offered a scholarship after Scott and Hobby saw him in person at Shrine Bowl practice. He committed immediately and didn't waver.

Hairston said his hometown Demon Deacons never showed any interest.

"I never thought I would play Division I-A football," he said. "I thought I-AA at best. I wasn't really thinking Clemson or any ACC school. The only inhouse visits I got was Clemson and S.C. State."

Hairston redshirted in 2006 and played 248 snaps last season. He played 19 snaps in a 44-10 victory over the Demon Deacons in the 10th game, and another 19 snaps in a last-second win at South Carolina two weeks later.

He stepped onto the big stage in the Chick-fil-A Bowl against Auburn. Starting right tackle Christian Capote was academically ineligible, leaving Hairston with the start and 75 snaps in the overtime loss.

Hairston played the first two games this year before grabbing the key to his friend's scooter. He was on the field for a few snaps in the Tigers' 20-17 loss to Maryland on Sept. 27, and he anticipiates starting and playing most of Thursday night's game as Clemson (3-2, 1-1 ACC) tries to turn around its season.

He says he's still dealing with some pain in the knee. But it's nothing compared to the pain of standing on the sidelines and watching his team suffer from a mistake he says he'll never make again.

"I'm trying to do everything I can not to be that weak link, even though I'm playing through pain that some people wouldn't want to play through," he said. "I'm doing everything I can to make sure they know that I'm sorry for it."