The trio could all be selected to represent Spain in a friendly clash with Ecuador, and will likely not return to London until 24 hours before the August 18 opener.
Torres, Azpilicueta and Mata look set to be back in London 24 hours before the team's first fixture against Hull City on August 18 should they take part in la Roja's friendly with Ecuador.
Despite television coverage allowing Chelsea an extra day to prepare for the Tigers clash compared to some of the club's Premier League rivals, Mourinho has hinted that the players are unlikely to feature against Steve Bruce's men.
"My lineup will depend a lot on which players go away with their national teams two days before the opening of the Premier League," Mourinho told reporters.
"If one has to go to Ecuador and comes back and arrives in London on Saturday without having slept after a 15-hour flight, coming in to train on Saturday morning, I don't think he is going to play on Sunday."
Chelsea is currently away on a tour of Asia and having won their first two fixtures, they will now face Indonesia All-Stars in Jakarta on Thursday, before flying to America for the next leg of its preseason preparations.