Gustavsson, 19, was Pittsburgh's top pick in the 2016 NHL Draft, drafted with the 55th overall selection in the second round. He was the third goaltender chosen.
This past season, the 6-foot-2, 184-pound goaltender spent a majority of the campaign with Lulea in Sweden's top league. He played in 15 games, going 4-8-2 with a .912 save percentage. Gustavsson also appeared in six regular-season games (2.09 goals-against average; .928 save percentage) and three postseason contests (0.95 goals-against average; .967 save percentage) with Lulea's junior team.
A native of Skelleftea, Sweden, Gustavsson was Sweden's backup netminder at the 2017 World Junior Championship, where he stopped 36 of 38 shots in his only appearance.
Back in the 2015-16 season, Gustavsson backstopped the Swedes to a silver medal at the 2016 Under-18 World Championship, taking home the tournament's 'Best Goaltender' honors.