Colorado Avalanche defenseman Erik Johnson is out indefinitely with a head injury.
Johnson last played in Monday's 3-2 overtime loss to the Phoenix Coyotes. He left the game early in the third period when he awkwardly took a check from Martin Hanzal.
The 24-year-old, who signed a four-year, $15 million extension last July, has just one assist in 11 games this season.
In 309 career games with the Blues and Avalanche, Johnson has recorded 27 goals and 101 assists.