Pulisic, the top American player, is recovering after testing positive for COVID-19.
He has said he is fully vaccinated.
He resumed training with the U.S. on Monday.
The U.S. team departed Nashville on a charter flight Wednesday. U.S. coach Gregg Berhalter was to address Pulisic’s status at a news conference later Wednesday in San Salvador, where the Americans play on Thursday night.
The start of World Cup qualifying was delayed for a year due to the coronavirus pandemic.
Because of the delay, the U.S. is playing three qualifiers in a FIFA window designed for two.
Pulisic is the first American to play in and win a European Champions League final, having helped Chelsea win the title last season.