The 22-year-old has been heavily linked with a move to Liverpool this summer, though Leipzig boss Ralph Hasenhuttl claims that "it is 100% clear" that the player will stay at the club this summer.
The Guinea international still has three years left on his Leipzig contract and Rangnick has revealed that he doesn't think the club will be able to convince him to sign a new deal this summer.
"I am not currently assuming that we will be able to extend his contract prematurely," he explained.
"I can assure you that Naby will be playing with us this season. All other scenarios also depend on how we do this season, how Naby plays himself and so on."
It is understood that the player has a £44.7m release clause written into his contract that will become active next summer but Rangnick shunned the idea that perhaps it would be better to cash in on him during the current transfer window.
"It does not matter at all whether it's £67m or £90m. We have not developed for five years so that we can lose one of our best players in the first Champions League season," he asserted.
"That would make no sense. We want to be successful in sports."