The Predators said Johansen needed emergency surgery for the injury, which he sustained during a 3-2 overtime loss to the Anaheim Ducks in Game 4 of the Western Conference Final on Thursday.
Johansen, who leads the Predators with 13 points (three goals, 10 assists) in 14 Stanley Cup Playoff games, played 27:28 in Game 4 and was plus-1 with one shot on goal. He is expected to need 2-3 months to recover.
The best-of-7 series is tied 2-2 with Game 5 at Anaheim on Saturday (7:15 p.m. ET; NBC, CBC, TVA Sports).