The winger has been absent from the club since his failed move to league leaders and Saturday's opponent, Manchester City in the January transfer window.
And the Foxes coach has called on the Algeria international who is set to miss out on the trip to the Etihad Stadium - his third consecutive game - to return to the club.
“I think Riyad is not available for Saturday’s game,” Puel said in his pre-match briefing on Thursday.
“I hope Riyad can get his head right and come back with us and work hard. The best way is for him to come back and enjoy his football.
“He is a magnificent player and he enjoys his football. He loves his team-mates, and that’s important. He loves to touch the football but he needs to come back right. I hope he can come back with a good attitude and prepared to work, but he will need time, and time to be match-fit.
“It’s important this remains inside the club and private, not in the public. The most important thing for me is to keep Riyad and the club and the fans united and in a good way about this. It is important to keep a good feeling together through these difficulties.”
Mahrez played a pivotal role in the resurgence of Leicester City after a disastrous start that culminated in the sack of erstwhile gaffer Craig Shakespeare.
The former African Player of the Year has contributed eight goals and seven assists in 24 league appearances for the eight-placed Foxes this season.