Gustavsson, 30, was invited to training camp on a tryout agreement and played well enough to earn the backup role behind starter Tuukka Rask.
Gustavsson played for the Detroit Red Wings from 2012 to 2015, appearing in 41 games and posting a 21-10-6 record. He also spent three seasons in the Toronto Maple Leafs organization from 2009 to 2012. Overall, he has a 60-55-21 record, including a 2.89 goals-against average and a .901 save percentage.
He also represented Sweden in the 2014 Olympics and earned a silver medal.