フレット・ルッテン
In 2007–08, Mulder had his first coaching experience: he started the season as an offensive trainer in Twente, then rejoined another former side, Schalke 04, in April 2008, working with former teammate Michael Büskens as replacements for dismissed Mirko Slomka, a situation which occurred again in 2009, after the sacking of Fred Rutten, being joined then by another former club player, Oliver Reck.