The former Reading man played his last game for the Tractor Boys in the 3-1 defeat to Nottingham Forest.
Jewell said that the Iceland international had decided to leave Portman Road despite only moving to the club in the summer.
"He's terminated his contract," Jewell told reporters.
"We came to an agreement with him and his agent early last week. It just hasn't worked out for him or for us.
"He's been a terrific professional but sometimes it just doesn't happen. I think Ivar accepts that and we accept it."
Jewell has also said that he does not want any more players leaving the club.