The Liverpool midfielder joined his Germany team mates this week for the matches against Spain and Brazil but had to break off training on Wednesday.
"Emre Can will not be in the squad tomorrow because of the back problem he brought with him from Liverpool," Loew told reporters. "He tried to train yesterday but broke it off because it was pinching a bit.
"Maybe Saturday he can return to training and hopefully play a role against Brazil (next week)."
Loew said he would not be using the same starting lineup in both games as the world champions launch their preparation for their World Cup defence in Russia in June.
He said, however, he would start against Spain with the spine of his World Cup-winning side with places for Jerome Boateng, Toni Kroos, Mats Hummels, Mesut Ozil and Thomas Mueller.
"I think tomorrow the structure will be around Jerome, Mats, Mueller, Kroos and Ozil who will start," he said.
"I am not planning to play the same players in both matches. I want to try things out."
Loew has a big pool of players to chose from for the tournament in Russia and said he had still not ruled out Borussia Dortmund trio Mario Goetze, Marco Reus and Andre Schuerrle, all of whom did not receive a call up for these two games.
"I have talked to Mario and I was of the opinion that he was not at the level we would want," Loew said of Goetze, scorer of Germany's World Cup-winning goal in 2014.
"He is ambitious and he is in no way ruled out," the coach said. "Neither is Marco Reus. I would not have nominated him anyway after his long injury break. He needs to maintain a rhythm now for the coming weeks."
Loew said Schuerrle, who set up Goetze to score in the 2014 final, had experienced a dip in form earlier in the season but was now improving.
"He played few matches in the first half of the season but he is now rising and we know how to appreciate what Andre can do. He is for us still an issue for the World Cup."
The Germans have been drawn in Group F at the World Cup in June, along with Mexico, South Korea and Sweden.
(Reporting by Karolos Grohmann; Editing by Toby Davis)
