The Rovers midfielder will line up against his Norwegian team-mate when Rovers take on the Cottagers at Ewood Park on Saturday.
Hangeland has been persistently linked with a move to a bigger club after impressing since arriving at Craven Cottage in January 2008 from FC Copenhagen.
And Pedersen believes it is only a matter of time before the 29-year-old moves on.
He said: "I have known him for a long time. He has been doing really well.
"He did well at FC Copenhagen and when he played for Norway.
"It is no shock clubs like Arsenal have been linked with him. I think it is only a matter of time before one of those clubs buys him.
"There was talk about whether he would go with Roy Hodgson to Liverpool.
"He is a fantastic player and a fantastic person. I think that he will get a bigger club.
"He is happy at Fulham. But he is a professional and if he continues performing like he has been, it is hard to see him not being hunted by a big club."