Khedira, who had played in all of Germany's matches at the tournament, was withdrawn early in Saturday's game after over-stretching during a challenge for the ball.
"Sami Khedira won't play for us on Thursday. We will do everything for him to be available for a potential final," Loew told reporters of the 29-year-old Juventus player.
"I will have to bring in new names. There will be personnel changes in the lineup."
Germany are already without suspended central defender Mats Hummels and injured striker Mario Gomez, who will miss the rest of the tournament after also picking up an injury in the shootout victory over Italy.
Gomez, who will remain with the team, is the only specialist striker in the German squad.
Loew said he had enough options in midfield, naming Emre Can as one of Khedira's possible replacements due to his versatility.
"He is a player who can be used in a lot of different positions. In training, he has been very convincing. Physically he is very strong and skilled. I think that a player like Can would do our game a lot of good."
Captain Bastian Schweinsteiger was also a doubt with a knee ligament injury and if he did not fully recover by Thursday, he would not play, Loew said.
"We will not put our head in the sand. We will try everything with the players that are doubtful," the coach added.
"One thing is clear: I will definitely not let play anyone who is not 100 percent fit. I hope and wish that Bastian can make it.
"I made the mistake many years ago (of fielding a player who was unfit) and I won't make it again," he said, refusing to name the match he was referring to.
"The thoughts we have should not go back to the past but go forward. I fully trust all my players. They are training at a high level, they are physically in very good shape."
(Reporting by Karolos Grohmann; Editing by John O'Brien)
