Callahan, 26, played in five games with the Boston Bruins last season, averaging 12:59 in ice time per game. He also skated in 56 games for the Providence Bruins of the AHL, recording two goals and 16 points, while also leading all Bruins defensemen for plus/minus with a plus-30 rating. Callahan also appeared in four Calder Cup Playoff games and recorded one assist.
The Franklin, Massachusetts native made his NHL debut with Boston on January 14, 2025 against the Lightning. He has played in 22 career NHL games, all with the Bruins. Callahan has played in 241 career AHL games, all with Providence, recording nine goals and 52 points. He has also skated in 20 career AHL postseason games with five assists.
Before turning pro, Callahan played four years at Providence College where he served as captain. He was originally selected by the Arizona Coyotes in the fifth round, 142nd overall, of the 2018 draft.