
John Terry, Michael Ballack, Wayne Bridge, Arjen Robben, Andriy Shevchenko and Didier Drogba will all definitely miss that first game, while Petr Cech, Claude Makelele, Salomon Kalou and Paulo Ferreira remain doubtful.
But Mourinho insisted that the "spirit" in the club will see them through, insisting that he and his players are "a happy family."
Chelsea's has been a relatively quiet summer, with just centre- back Tal Ben Haim, midfielder Steve Sidwell, winger Florent Malouda and forward Claudio Pizarro arriving over the summer.
"I'd say that only Pizarro has come in to bring us something different because he is a different striker than what we already have and when we want to play many times with two strikers we need that extra man with his quality because Sheva (Andriy Shevchenko), Didier (Drogba), (Salomon) Kalou are different players to Claudio," Mourinho said.
"The reality of Sidwell, Ben Haim, Malouda is to protect us against things (the injuries) that happened last season."
Champions Manchester United begin with a home game against Reading, who, having lost Sidwell, face the traditional second-season struggle to prove their first season after promotion was not a fluke.
United will not have forward Carlos Tevez available as his protracted registration drags on, but assistant manager Carlos Quieroz insists they are ready for kick-off.
"We are ready," he said after United sides comfortably beat Dunfermline and Glentoran in friendlies.
"There is no doubt we believe the boys are fully prepared. We realise it is a different ball game now.
"The Premier League is starting, it has a different atmosphere, different problems and there is a different intensity."
Last season's player of the year, Cristiano Ronaldo, is a slight doubt with an ankle problem. Nani, who has been in fine goal-scoring form in pre-season, stands by.
Liverpool are the first of the big four to play, taking on Aston Villa on Saturday evening, while Arsenal begin at home to Fulham on Sunday lunchtime.
The season's first game, on Saturday lunchtime, sees Sunderland, promoted in Roy Keane's first season as manager, take on Tottenham Hotspur, who will be without centre-back Ledley King and winger Aaron Lennon due to injury.
Craig Gordon, signed this week as Britain's most expensive goalkeeper, should make his debut for the Black Cats.
DPA