The 25-year-old Spooner scored 11 goals and added 28 assists for Bruins during the 2016-17 campaign.
The Panthers traded Grimaldi to the Avalanche on June 23, 2016 for goaltender Reto Berra. The 24-year-old spent most of the past season with the San Antonion Rampage, where he produced 31 goals and 55 points in 72 games.