Mahrez has been AWOL from training and indeed matches since Leicester refused to sell the Algerian international to City in the latter stages of the January transfer window.
After missing the team's last two league games against Everton and Swansea City, it had been hoped that the attacker would return to training this week ahead of the trip to Manchester.
Puel, however, has admitted that "there is no news" regarding Mahrez's situation as the in-form playmaker continues to distance himself from the King Power Stadium.
"There is no news. I hope Riyad can get his head right and to come back with us and to hard work. The best way is to come and to enjoy his football," Puel told reporters.
"Riyad is a magnificent player and he loves football. He loves his relationship with his friends and teammates. He needs to come back and to play, to touch the ball.
"I don't want to comment and give details of our relationship with Riyad. It is important to all details remain inside the club and not in the public.
"I can understand all this speculation. I think it is important in this difficult time to keep all players, and club, united. Together, to look forward and continue the hard work on the pitch."
Mahrez was reportedly left "very depressed" by his failure to secure a move to City on transfer deadline day, and it has since been claimed that the Citizens will not return with an offer at the end of the season.
The attacker has scored eight times and registered eight assists in 24 Premier League appearances this season.