When did teams start expanding their rosters and using more lines? I was looking at the early days of the NHL and it seems that teams really only had 15-16 guys dressed for games...some seemed to only have 4-5 defensemen as well. Was the game more "iron man" back then where maybe you only played 2-3 forward lines and 2 defensive pairings. Curious if anyone can shed some light on the topic. TYIA!!!