The size issue goes not exist in today's nhl. Shaw, Lehkonen, and Gallagher are probably montreal's 3 best players at winning puck battles. Gallagher has said he wins those battles because of his size.
Considering the Habs are in St. Louis tonight, this could solely be related to that but Montreal has had two scouts at two of the last three Blues home games. I know Bergevin said he wouldn't go after rentals but I think he meant more of impact rentals that would cost a key part of the future. St. Louis has a couple of d-men I could see Bergevin being interested in if it's a low cost (Gunnarsson/Bouwmeester).