The 20-year-old Fiala was hit by Blues defenceman Robert Bortuzzo and went hard into the boards behind the St. Louis net at 1:46 of the second period Wednesday night. His injury led to a 17-minute delay while Fiala received medical attention. He was taken off the ice on a stretcher to the hospital.
Nashville general manager David Poile said in a statement that Fiala had surgery at Barnes-Jewish Hospital in St. Louis and will start rehabilitation when he returns to Nashville.
"It’s a tough loss, there’s no question," Predators captain Mike Fisher said. "Everything went well I guess and he’s doing well. That’s the main concern. He’s one of those guys that’s played really, really well so far in the playoffs and is a big part of our team."
Nashville won 4-3 for a 1-0 second-round series lead.
The 11th draft pick in 2014, Fiala scored two goals in the Predators’ first-round sweep of Chicago.
Coach Peter Laviolette said Fiala had worked his way onto the power play and was among the team’s top six forwards.
"He wants to get better, and it was getting to a point where he really was a difference-maker with the puck on his stick, as you saw in that overtime goal in the first round," Laviolette said. "It was a really, really nice play and a patient play. It’s unfortunate for an accident like that to happen on the ice."