Usain Bolt has broken multiple records at the 2008 Olympics in Beijing. His speed and size have football fans thinking of a possible transition to the NFL, like other former track stars did in the past. (Photo by Itsuo Inouye/Associated press)

"Bullet" Bob Hayes was an Olympic gold medal winner and Super Bowl champion for the Dallas Cowboys. Hayes, once considered the fastest man in the world, changed the game of football as opponents started using a zone defense, because no man could cover him one-on-one. Hayes, however, wasn't just a track star turned football player -- he played halfback at Florida A&M. He was selected to three Pro Bowls and is a member of the Cowboys' Ring of Honor. (Photo by James Flores/NFL)

Carl Lewis was one of the most celebrated athletes in Olympic history, winning nine gold medals and one silver. Lewis was drafted in the 12th round of the 1984 NFL Draft by the Dallas Cowboys but never signed with the team. He also was selected in the NBA Draft by the Chicago Bulls. (Photo by Diether Endlicher/Associated Press)

Justin Gatlin garnered a lot of interest from NFL teams while serving a suspension from track and field. Gatlin, who won the 100-meter event in the 2004 Olympics, worked out with Arizona and Houston before landing an official tryout with the Buccaneers in 2007. He never signed with Tampa Bay. (Photo by Doug Benc/Getty Images)

James Jett ran with Carl Lewis on the gold medal-winning 4x100-meter relay team in the 1992 Olympics. Jett, who played college football at West Virginia, signed with the Los Angeles Raiders in 1993 and immediately led the NFL by averaging more than 23 yards per reception. Jett's best season of his 10-year career came in 1997 when he scored 12 touchdowns. (Photo by J.D. Cuban/Getty Images)

Renaldo Nehemiah was a world-record holder in the 110-meter high hurdles -- the first to run it in under 13 seconds -- when he signed with the 49ers in 1982. (He also drew interest from the Steelers.) Nehemiah played three nondescript seasons in the NFL and was not a major factor on the 49ers' Super Bowl-winning team in 1984. (Photo by Amilcar de Leon/Associated Press)

Ron Brown was drafted by the Cleveland Browns in 1983 and competed in the 1984 Olympics in Los Angeles, winning the gold in the 4x100-meter relay (with Carl Lewis). Brown joined the Los Angeles Rams in 1984 and led the NFL in kick returns the following season. Brown was selected to the Pro Bowl in 1985 and finished his career in 1991 with 98 receptions for 1,791 yards and 13 touchdowns. (Photo by Tim de Frisco/Getty Images)

Willie Gault had his Olympic dreams dashed when the United States boycotted the 1980 Moscow Games. Gault, a first-round pick (18th overall) of the Bears in 1983, was a key member of Chicago's Super Bowl XX championship team. He finished his 11-year NFL career with the Raiders. (Photo by George Rose/Getty Images)