"The lad is aggressive, fanatstic in the air and can read the game well. He is a leader on the field and he will bring tremendous competition at the back for us.
"I wouldn't have brought him here unless I thought he had the attributes to be a hit in the Premier League."
Hagen will go into the squad for Saturday's game with West Ham United and is hoping for a chance with the Latics.
He said: "Yes I was delighted when everything was solved. "Age [Hareide] knows Steve Bruce and recommended me to go there and that made it all easier.
"Age told Bruce what kind of player I am and Bruce wanted an old head in his defence, one with experience and knows what's happening. I take that as a compliment that he chose me and I hope I get a lot of time on the pitch."