That fee could rise by a further £360,000 for the Sweden under-21 international depending on add ons.
Mowbray said: "I'm delighted to welcome Jonas to the club. He's got different assets to our other centre-halves.
"Jonas is comfortable on the ball, can pick a pass and also has a real winner's attitude. He's been brought in to increase competition at centre-half and I'm looking forward to working with him and helping to develop his career in the Premier League."




