The Guinea international will move to Anfield on July 1 after the Reds triggered his £48m release clause last summer.
But Hasenhuttl believes the 22-year-old hasn't played to the best of his abilities this season.
"Naby is not as consistent this year as last year," Hasenhuttl said. "It's important that he brings his expectations back to normal levels.
"I'm not one who wants to motivate with fear. I don't immediately get the whip out in the classic sense and I don't kick the players non-stop."