What is a Black Ace in hockey?

Around the time of the NHL playoffs, you often hear some players on the roster referred to as "Black Aces."

Who are the Black Aces on a roster, and where did that name come from?

WHAT IS A BLACK ACE?

The Black Aces are the extra players added to a roster for a team's playoff run after their own season is over in the minor-leagues or elsewhere. The Black Aces practice with the team and are expected to be ready to step into the lineup if any of the regular players in the lineup are unable to play.

The NHL's 23-man roster limit ends at the trade deadline, and there is no salary cap in the postseason, allowing teams to carry as many Black Aces as they wish. The Black Aces typically consist of most…