Buffalo sent the 68th overall pick in the 2017 draft to Montreal for the pending restricted free agent.
In 225 career National Hockey League regular-season games, the 6-foot-2, 205-pound Beaulieu owns 60 points (seven goals, 53 assists), adding four points in 17 career playoff games. Montreal lost that game 3-1 at Madison Square Gardens and lost the series 4-2. Opportunity knocked for him last season but according to a June 13 article by Joey Aliferi of Pro Hockey Talk, "Expectations were high, but things definitely didn't work out as planned".
The deal comes in the wake of the club swapping another young defenceman, prospect Mikhail Sergachev, for Tampa Bay Lightning forward Jonathan Drouin, on Thursday.
"Obviously, it's disappointing", Beaulieu said of being a healthy scratch against NY, per the Montreal Gazette.
While the Canadiens weren't expected to protect the 2011 first-round pick, Buffalo did at the expense of exposing two more high-profile and higher-priced defensemen in Zach Bogosian and Josh Gorges.
We won't know until next week, but the Sabres did themselves some good by landing a d-man like Beaulieu.