OL signed Denayer in a permanent deal this week for €10m.
Maurice said: "Jason's transfer accelerated last week. He is a player we know well because we followed him for three years. Manchester City has agreed this time to give him to us. He is going to be valuable for the team because he is fast, is solid in the duels and able to play out the ball properly.
"He is still a young player but he is already very experienced. He has just been crowned Turkish champion with Galatasaray and has also proven himself in the Premier League.
"He wanted to embark on a new adventure and we have the means here to help him reach the Belgian national team."