Usain Bolt, the men's world-record holder in the 100 and the 200 meters, will be the main attraction at the Penn Relays this weekend. But he will not be the only intriguing tall young sprinter at Franklin Field. Ryan Bailey, an American who just turned 21, will run the opening leg for one of two Team USA relay teams that will compete against Bolt and his Jamaican teammates in the 4x100 on Saturday. Unlike many others competitors who have run before huge crowds in the Olympics or at major championships, Bailey will be unaccustomed to the throng expected here for the 116th edition of this three-day relay carnival. 'I've heard there's upwards of 70,000 people,' Bailey said Thursday at the team hotel. 'That's a lot of people to see someone run around a track.' Bailey is the best sprinter to come out of Oregon, a state known more for producing distance runners. He turned pro in August, signing with Nike after an abbreviated high school career followed by a year in junior college. He is so new to top-flight competition that he does not yet have a biography on the USA Track and Field website, although that will no doubt change soon. At the UTEP Invitational last week, his first event of the season, Bailey finished second in the 100 to Churandy Martina, the fourth-place finisher at the Beijing Olympics, then defeated Martina in winning the 200. His times -- 10.09 seconds in the 100 and a personal-best 20.40 in the 200 -- were among the fastest of the new outdoor season. Next Saturday, Bailey will begin his international tour. First stop: the Jamaica International Invitational, where he is very likely to encounter Bolt in the 200. At 6 feet 4 inches, Bailey, who has run 10.05 in the 100, is in the mold of the 6-5 Bolt, who defied the conventional wisdom that height is a disadvantage for sprinters when he set his first 100 world record, 9.72, at the age of 21 two years ago at Randalls Island. Bailey looks more like a football player, which was his choice sport until the end of high school. Becoming a track star was far from predetermined. Bailey's nascent career has already been marked by false starts. He did not step foot on a track until his sophomore year, and was an irregular competitor throughout high school, the result of injuries, poor grades and disciplinary problems. 'The curiosity with Ryan is, What is his potential going to be if he stays healthy for a few years?' said John Parks, 48, his coach and mentor since high school. 'He's still young. He has had a third of the races that most guys that age have had.' The youngest of eight children by seven years, Bailey grew up with his single mother, Debra Galban; his father was rarely around. His mother remarried when Bailey was 7, but his stepfather soon went to prison, and she moved around with her son almost every year to stay close to her husband. They did not have much, and his mother, who is disabled, collected a fixed income. Bailey found his way into gangs and fights. New schools brought new disciplinary problems. Early in the spring of his sophomore year at Douglas McKay High School in Salem, he met Parks, a social studies teacher and track coach. Skipping class one afternoon, Bailey and a friend looked at a board listing the school records in track. Neither realized those were also state records. 'I can get those,' Bailey said. He did not know Parks was standing behind him. Parks told Bailey, 'Why don't you come out and prove it?' His mind squarely set on football, Bailey brushed off Parks. 'I thought track was for a bunch of nerds,' he said Thursday, laughing. Bailey never went to see Parks at the track, but showed up there one day to make up a physical education class. Wearing baggy jeans and basketball shoes, Bailey passed Parks, who had his stopwatch ready, as he peeled off a lap. Parks recalls clocking Bailey at around 51 seconds for 400 meters. Parks saw a future superstar. He told Bailey he was 'smooth like ice.' Parks finally persuaded Bailey to join the team. For his first meet, Bailey did not have track spikes, so his teammate lent him a pair at least a size too small. Out of the blocks, Bailey broke a toe. After he returned from his injury, this time with proper footwear, he broke a toe on his other foot. The next year, as a junior, Bailey had a setback away from track, being expelled for fighting. He went to an alternative school and then returned to McKay. That spring, in an altercation with a former acquaintance, Bailey was stabbed three times with a small pocketknife. He again missed most of the track season. As time passed, Parks grew closer with Bailey, becoming his surrogate father. Parks would pay for shoes, dinner and travel expenses for meets around the country. Parks had seen other students return to troubled lives. 'I was just determined to not let him fall by the wayside,' he said. Bailey said of Parks: 'He's been a father for me, like I never really had. It's been a blessing.' In his senior year, despite more injuries, Bailey finally had the chance to show his natural talent. At the 2007 state championships, he set state records in the 100 and 200. The focus now, Parks said, is on technical development, molding all that untapped potential. Parks has guided Bailey along slowly in recent years, successfully avoiding injuries. 'I've been injury prone every single year I've done track,' Bailey said. 'I feel like this is the year for me.' It is that confidence that gives Bailey room for one more prediction. 'I definitely can see myself being one of the greats in the sport,' he said. 