The La Liga side flew out to the States for the 17-day tour on Saturday, but Xavi was forced to remain at Barcelona airport due to his previous visits to Iran - a country that has endured tense relations with the US in recent years.
The Spaniard has visited Iran three times over the past five years during his time with Qatari club Al Sadd as both a player and a manager, which the Mirror are reporting has caused the delay.
The report has revealed that additional documentation is required to justify so many visits to the Middle East in recent years, something which Barcelona believed was due to arrive on Friday.
However, a delay in the documentation has forced the 42-year-old to remain in Catalonia until Monday according to the report, with the rest of the squad and backroom staff continuing with the beginning of the tour without him.
Barcelona's tour of the US will start on 20 July against Inter Miami in Florida, before facing rivals Real Madrid in Las Vegas four days later.
Serie A outfit Juventus will be their third opponents in Dallas on 26 July, before concluding their training camp with a clash against New York Red Bulls on 31 July.