Montreal coach Michel Therrien made the announcement Tuesday.
Pacioretty exited the game at Florida in the first period after a check by Panthers defenceman Dmitry Kulikov caused him to slide into the end boards behind the Florida net.
Kulikov received a two-minute interference penalty.
Pacioretty was to meet with team doctors on Tuesday.
His 37 goals have him tied for fourth in the NHL this season, and he also leads Montreal with 67 points in 80 games.
Thursday's home game against Detroit will be the first contest Pacioretty has missed since November 2013.
Heading into Tuesday's action, the Canadiens lead the Atlantic Division by two points over Tampa Bay, and are three points behind the New York Rangers, who have the best overall record in the NHL.