Semin was injured Saturday during the Hurricanes' 4-2 loss to the St. Louis Blues on a hit by Blues defenseman Alex Pietrangelo. Semin returned to the ice briefly after the hit, but left the game for good in the second period.
The 29-year-old was out of the lineup Monday against the Boston Bruins.
Semin, who was second on the Hurricanes with 44 points last season, has three goals and six assists in 20 games this season.
I've been getting frustrated lately, and the only thing keeping me sane was the team winning and other people stepping up and scoring. Then you just kind of let it go and realize you can end the series with one shot, that frustration goes away for a brief moment, and that's what happened.
— Montreal forward Max Pacioretty after scoring the series-winner in Game 4 -- his first career playoff goal -- to eliminate the Lightning and send the Canadiens into the second round