New York - Nick Symmonds, the 800m silver medallist at the 2013 world athletics championships, is notably absent from the 130-athlete team named on Monday to represent the United States at this month's worlds in China.
Symmonds was left off the U.S. team after refusing to sign a contact that requires team members to wear Nike gear to official functions.
Justin Gatlin, the fastest man in the world this year over 100m and 200m, spearheads a team that also includes five defending world champions.
Gatlin's showdowns with world record-holder Usain Bolt of Jamaica are expected to be among the highlights at the Bird's Nest in Beijing from August 22-30.
Other prominent athletes on the U.S. team include Olympic women's 200m champion Allyson Felix (200m, 400m and relay squads) and Olympic 10 000m silver medallist Galen Rupp (5 000m, 10 000m).
The Alberto Salazar-coached Rupp has been in the news recently following a British Broadcasting Corporation investigation that claimed Salazar had violated anti-doping rules, including giving Rupp the banned anabolic steroid testosterone.
Salazar and Rupp have both denied the claims.
American athletes who will return to defend their individual world titles are Ashton Eaton (decathlon), LaShawn Merritt (400m) David Oliver (110m hurdles), Brittney Reese (long jump) and Brianna Rollins (100m hurdles).
But the absence of Symmonds quickly became the big talking point in American track and field on Monday after the runner refused to sign the contract over the apparel restrictions and was left off the team.
Symmonds, who finished fifth in the 800m final at the 2012 Olympics before improving to second at the world championships the following year, is sponsored by Brooks, a commercial rival of Nike.
Symmonds won the U.S. trials in June.