The 28-year-old Diaz had 11 assists and 12 penalty minutes in 46 games for the Canadiens this season.
The native of Baar, Switzerland, has 41 points (four goals, 37 assists) and 48 penalty minutes in 128 NHL career games.
Weise never seemed to fit into the plans of Canucks coach John Tortorella. The Winnipeg native had three goals and nine assists and 42 penalty minutes in 44 games this season, mostly while playing on the fourth line.
In 162 career games, the 25-year-old has 10 goals, 16 assists and 185 penalty minutes.