Ott will join the Blues as an assistant coach, effectively ending his playing career.
Ott had an assist and seven hits over 11:29 of ice time in Montreal's 4-1 win over the Rangers on Saturday.
Ott will play his first game with the Canadiens on Saturday against the Rangers.
The Canadiens acquired Ott from the Red Wings Tuesday in exchange for a sixth-round draft pick in 2018.
Ott contributed a goal, an assist and a plus-2 rating in Sunday's win over the Penguins.
Ott (shoulder) is likely to be scratched from Tuesday's home tilt with the Blue Jackets, despite his recent activation from injured reserve, Helene St. James of the Detroit Free Press reports.
Ott (shoulder) was activated from the injured reserve Monday, Helene St. James of the Detroit Free Press reports.
Ott is dealing with a shoulder injury that will see him go on injured reserve, MLive.com reports.
Ott has hit the scoresheet just once in the last 18 games, giving him four points in 37 contests this season.
Ott scored his first goal of the season Thursday night, contributing to a 3-1 home win over the Canucks.