The Mirror says fans are stunned after a message appeared on Mahrez's Facebook page claiming the midfielder is leaving football after consultations with doctors.
The out-of-the-blue 'announcement' appeared on Facebook tonight, prompting a huge reaction from fans.
It is not yet clear whether the footballer has been hacked.
The message said: "After the last consultation with many doctors, I've decided to stay away from football.
"As my time as a football player comes to an end I would like to say few words.
"I want to thank everybody for the kindness and support they have shown me in this incredible city , you will be always in my heart."