Blues coach Ken Hitchcock disclosed his decision Monday.
Halak was injured in the second game of the Blues' first-round series against San Jose, leaving with an undisclosed lower-body injury that is believed to be a sprained left ankle he suffered during a collision with teammate Barret Jackman.
St. Louis had the deepest goalie tandem in the NHL this season. Brian Elliott led the NHL with a 1.56 goals-against average, including nine shutouts.
The NHL has not yet announced specific dates for the Blues-Kings series.
Obviously there's a lot of expectations around me but it's something I try not to focus on. I'm just trying to go out there, be myself on the ice every day, try to get better, be myself around the guys in the locker room. I think that's what's made me successful and the person that I am.
— Sabres forward Jack Eichel on transitioning from college hockey to the NHL