The Holland international has joined Feyenoord on a season-long loan.
Clasie told RTV Rijnmond: "For me there was one thing: I wanted to go back to Feyenoord.
"I wanted to get out of there, because I have not played much in recent years. In the first season I did that, but after that season it became less and less.
"I wanted to play football again.
"Mentally I feel a lot stronger than before. I have kept a bond with the club. It has been more than half of my life. In England, I was a happy supporter on television when Feyenoord became national champion."