"It's terrible. At the same time, though, when something like this comes up, this goes way beyond hockey. This is about the person," said Penguins head coach Dan Muse. "And I think we're all very thankful and grateful that the medical staff here was able to figure this out as quickly as they did, and now, they can start to do everything they need to just to get him back on track and take care of him."
The 25-year-old will rehab in Pittsburgh with the Penguins' medical team and the experts at the University of Pittsburgh Medical Center.
Pittsburgh's young forward only played in three games in the previous two seasons for the Penguins due to his return to Sweden for personal family matters, playing for Timra in the Swedish League.
But he returned to the NHL this year after signing a two-year, $1.55 million contract.
He has one goal and three assists through 13 games this season for a Penguins team doing surprisingly well with a 9-4-3 record.
Unfortunately for Hallander, he'll miss out when the team travels to his home country of Sweden for two games on November 14th and November 16th against the Nashville Predators for the NHL's Global Series.