Forward Timothy Weah is hurt and will miss the United States' opening three World Cup qualifiers.
The U.S. Soccer Federation said Weah will not report to Nashville, Tenn., ahead on Thursday's opener at El Salvador.
The 21-year-old Weah is a son for former FIFA Player of the Year George Weah, Liberia's current president.
Christian Pulisic was among 16 players who started training with the U.S. team on Monday at Lipscomb University.
Nine others were traveling to Nashville after playing Sunday matches with their clubs.
Pulisic, the top American player, started training with the U.S. team after clearing COVID-19 protocols.