Coyotes general manager John Chayka said Sunday that Raanta underwent a procedure on the injury that revealed more damage than originally thought.
Raanta was placed on injured reserve this weekend, though Chayka said the 29-year-old could be out for the rest of the season.
Raanta has been limited to 12 games due to injury this season and hasn't played since leaving with a lower-body injury against Minnesota on Nov. 27.
The Coyotes acquired Raanta in a trade from the New York Rangers prior to the 2017-18 season after dealing away No. 1 goalie Mike Smith. Arizona hoped Raanta would fill the No. 1 role after being a backup, but he has struggled with injuries during two seasons in the desert.
Raanta played 47 games last season and is 5-6 with a 2.88 goals-against average this season.