The Sabres drafted Samuelsson during the second round (32nd overall) in 2018. The son of longtime NHL defenseman and coach Kjell Samuelsson, Mattias was touted then for his leadership - he served as captain of Team USA at both the U-18 and U-20 World Championships and as an underclassman at Western Michigan University - and for his poise as a defender.
He has established himself as a quick learner since turning pro ahead of the 2020-21 season, which he split between Rochester and Buffalo. He blocked a shot during the Prospects Challenge last September that cost him his training camp and a chance to make the Sabres' opening day roster, but quickly established himself as a full-time member of the defense corps upon joining the team in January.
He averaged 21:19 of ice time in 22 games from March 10 on, during which he led the team in hits (63) and blocked shots (32). He showed a propensity for using his 6-foot-4 reach to strip the puck from opposing forwards when defending the rush. (That skill prompted Dahlin to refer to Samuelsson's stick as a "cobra.")
"We don't talk about him enough," Dahlin said. "He's an amazing guy on and off the ice. … It's super easy to have a guy like that. He plays the right way and (goes) great places with the puck. He's a guy that you can really trust."
Off the ice, Samuelsson has a reputation as one of the comedians in the Sabres' room (and a mic'd up star).