Gustavsson arrived in the NHL in 2009 to considerable fanfare, having starred in the Swedish Elite League. The 6-foot-4, 201-pound goaltender, nicknamed "The Monster," has become a reliable backup goalie in the NHL, while dealing with some frightening health problems.

His medical issues surfaced on his first day on the job at his first training camp with the Toronto Maple Leafs in September 2009, when he needed surgery for an accelerated heart rate. It was the first of three such surgeries Gustavsson would need in his first two NHL seasons.

Gustavsson, a native of Danderyd, Sweden, was determined to keep playing while managing his condition, and he appeared in 42 games as a rookie. In 2010, the Toronto hockey writers nominated him for the Bill Masterton Trophy, which is awarded to the player who best exemplifies perseverance, sportsmanship and dedication to hockey.

He earned a second Masterton nomination in 2015-16, after Gustavsson, while playing for the Boston Bruins, was taken to the hospital on Jan. 26, 2016 with an elevated heart rate he experienced during a game against the Anaheim Ducks. He was released after no abnormal heart symptoms were detected.

Gustavsson delivered strong goaltending to the Maple Leafs for three seasons, sharing the job with James Reimer, before playing behind Detroit Red Wings starter Jimmy Howard for parts of three seasons from 2012-15. In Boston, he backed up Tuukka Rask in 2015-16 before signing a one-year, free agent contract with the Edmonton Oilers on July 1, 2016.