Germany striker Mario Gomez has been ruled out of the rest of Euro 2016 with a torn hamstring.
Schweinsteiger has picked up a ligament strain while Khedira is suffering from an adductor injury.
"It is very disappointing when, at this crucial stage of the tournament, important players are ruled out," Low said.
"I'm especially sorry for Mario. He has put in some strong performances at the European Championship and has helped the team not only with his goals.
"We accept the situation and have to find solutions. The quality of the squad is high, I have full confidence in all my players.
"We will be ready on Thursday and look forward to the semi-final in Marseille."
Mats Hummels will definitely miss the last-four clash due to suspension after picking up a second yellow card of the tournament against Italy.