The club announced that no further details will be shared and asked that the 35-year-old's privacy be respected. The Swede is the team captain of Tampa Bay.
He has missed the club's last three NHL games due to illness.
Hedman was part of Sweden's Tre Kronor team when it reached the Olympic quarterfinals against the United States in February in Milan. He missed the quarterfinals after suffering an injury during warm-ups.
In December, the defender had elbow surgery and was racing against time to be ready for the Olympic tournament.
During his years in Tampa Bay, he has helped the team win the Stanley Cup twice.
