Tyson Gay, one of the top sprinters in the United States, and 2004 Olympic gold medalist Shawn Crawford head the team that will compete in the USA vs. the World races Saturday at the Penn Relays, USA Track and Field said yesterday.

Lauren Williams, Allyson Felix, Derrick Brew, Darold Williamson, Dee Dee Trotter and Monique Henderson are other Olympic medalists who will be in the pool of athletes from which the U.S. teams can draw for the six races.

In a release announcing the selections, USATF said final lineups for the relays in the eighth annual competition will be announced Saturday. Men and women both run the 4x100 and 4x400; the other relays are a men's distance medley and a women's sprint medley.

Jamaica, Kenya, China, Russia, Germany, Great Britain, Canada, the Bahamas and the Dominican Republic will challenge the United States in certain races. Some of the runners expected to compete are Sherone Simpson of Jamaica, the world's No. 1-ranked female sprinter; Jamaicans Michael Blackwood and Sanjay Ayre; and Olympic gold medalist Felix Sanchez of the Dominican Republic.

Asafa Powell of Jamaica, the world-record holder at 100 meters, had planned to run in one of the relays, but his manager told Reuters earlier this week that he would not compete.

The Americans won five of the six races last year, losing only the men's distance medley relay to a team from Kenya.

Gay and Crawford ran on the 4x100 relay team that won in 38.33 seconds. Gay, who ran for Arkansas in the Penn Relays, set personal bests during the 2006 season of 9.84 in the 100 and 19.68 in the 200.

Williams ran a leg on two winning women's teams - the 4x100 and the sprint medley - at last year's carnival. The former University of Miami star is the reigning world champion and 2004 Olympic runner-up at 100 meters.

Felix, who is expected to run in the women's 4x400, won the world outdoor championship at 200 meters.

Other U.S. athletes who competed at Penn last year and are scheduled to return include Brew, Williamson, Henderson, Wallace Spearmon, Hazel Clark, Rachelle Smith, LaShawn Merritt, Andrew Rock and Kerron Clement.