Low has claimed that the presence of Brant, Julian Draxler, Marco Reus and Thomas Muller made it difficult for him to select Sane, but the Germany manager has backed the attacker to be a key player in the future.
"That was a very close decision between him and Julian Brandt, which was made in favour of Brandt. Draxler, Reus and Muller are set. Leroy has a huge talent," Low told reporters.
"He will be back again from September. He has not arrived in international matches yet."
World champions Germany will open their 2018 World Cup campaign against Mexico on June 17, before also taking on Sweden and South Korea in the group stage of the competition.