This doesn't have to be the case- a professional hockey team has the ability to choose what players to roster through the draft and free agency processes. You don't have to have a roster 20 pounds less on average than other NHL teams.I made a quick evaluation and the Golden Knights players weight on average 20 pounds more than those of the Habs !
NHL teams also have the ability to both feed and strength and weight train their players. The Habs are not restricted from doing so to my knowledge.




