The Algeria international saw his second straight spot-kick saved in the Foxes' 1-1 draw at Aston Villa on Saturday.
Goalkeeper Mark Bunn denied Mahrez from 12 yards following Aly Cissokho's handball after Bournemouth's Artur Boruc also saved his penalty in a 0-0 draw earlier this month.
Leicester regained the Barclays Premier League lead by a point despite the miss - before Arsenal's game at Stoke on Sunday - but Ranieri will talk to Mahrez, with Jamie Vardy next in line.
"Now is not important if I change the penalty man,'' said the Italian
"I'll speak with him and then I'll choose.
"From the bench it was difficult to see if it was handball but if it's a penalty, it's a red card.
"We are very sad but also I say to the players 'if we make the performance the result is not important'
The performance was good because we played well in the first half
It's one point, it's okay, it's a derby - but we are disappointed.''
Shinji Okazaki opened the scoring only for Rudy Gestede to level with 15 minutes left to deny the Foxes the chance to go three points clear at the top.
Bunn saved Mahrez's penalty in just his second league appearance in almost three years to keep Villa in the game.
He has replaced Brad Guzan for Villa's last three games and boss Remi Garde has been pleased with his impact.
He said: "If you look at the previous week, Mark did well
I feel Mark gives a little bit more confidence to the team and what he did was good as well.
"If he had not saved the penalty, probably 2-0 down would have been too difficult
He kept us in the game."
Source : PA
Source: PA