Beaulieu is viewed by analysts as an upgrade to the Sabres D-corps with his size along with his ability to skate and move the puck.
The Canadiens will receive Buffalo's third-round pick (68th overall) in the 2017 National Hockey League draft.
Beaulieu, 24, was the Habs' first-round pick in 2011.
A former first-round pick from 2011, the 24-year-old rearguard registered four goals and 24 assists in 74 games during his most recent campaign. Beaulieu makes sense for the Sabres, though, as he's a smart two-way player who can work on the man advantage. After finishing his final season with the St. John's Sea Dogs, Beaulieu split time between Montreal and their AHL affiliate, the Hamilton Bulldogs.
Montreal was in danger of losing Beaulieu in the expansion draft, while Buffalo has room to protect him.
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.
Solano among areas affected by heat advisory
The hot conditions are labeled as a classic pre-monsoon heat event for the Southwest region, NWS said. Saturday's high is expected around 101 degrees, pushing up to around 107 by Sunday .
Taylor Swift's Music Returns to Streaming Services
The album, which was already streaming through Apple Music, is becoming available on Amazon.com Inc's streaming service , too. She says her return is a "thank you" to fans, in honour of her last album 1989 selling 10 million copies.