Kawhi Leonard has pulled out of USA Basketball's minicamp and three players were added to the roster.
Indiana's George Hill, Charlotte's Michael Kidd-Gilchrist and Oklahoma State guard Marcus Smart will train with the Americans next week in Las Vegas. The roster of young players now totals 29.
Smart helped lead the U.S. Under-19 team to the world championship earlier this summer.
USA Basketball says Tuesday that Leonard, who helped the San Antonio Spurs reach the NBA Finals, is rehabbing after a long season.
The Americans will practice for three days before holding an intrasquad exhibition game on July 25.