Mahrez has branded Maguire "a very good player", and has suggested that Leicester will find it difficult to keep hold of the 25-year-old.
"I have always believed that 'H' (Harry Maguire) is a very good player, he has shown that since the day he came to Leicester and the season he had last year," Mahrez told reporters.
"It doesn't surprise me to see how he has done at the World Cup. Of course he deserves to play higher but Leicester are a good club as well, so it's him who has to decide and we will see."
Leicester paid Hull City £17m to sign Maguire in last summer's transfer window.