Hallander fractured his leg playing for Lulea HF in Sweden on Tuesday and will be out through December.
Hallander was expected to have a big season after putting up 21 points in 45 games last year, but his injury could derail his development. Even with the injury, the 19-year-old could be a candidate for some minutes with AHL Wilkes-Barre/Scranton following the conclusion of his Swedish campaign. Drafted by the Penguins in the second round of the 2018 NHL Draft, the center could find himself in the mix for a roster spot heading into the 2020-21 season, assuming he is able to fully recover.