Ferguson has already said that Hernandez, suffering from concussion, will miss the start of the season and has now added that he is "still two to three weeks away" and "should be back at the end of August".
Carrick, meanwhile, is suffering from "tightness in his Achilles" after Edwin van der Sar's testimonial and Rafael is still recovering from an injury he suffered in the 2-1 friendly victory over Barcelona.
The Community Shield takes on an added edge this season as United take on local rivals Manchester City, but it has typically been treated as a friendly encounter and Ferguson has no plans to change his approach.
"It's very easy to get emotional about this type of game," he said. "I don't think we'll be changing our policy. I've always viewed the Community Shield as a stepping stone for the first game of the season and there are two or three players who will need a game [to boost fitness levels]."