Avalanche head coach Jared Bednar just announced the update to media members ... saying he's not sure when the Colorado center will be able to return to game action.

Bednar did say, though, that he expected MacKinnon to miss at least the team's next 3 games.

If you missed it ... the hit was scary as hell -- as MacKinnon was going up the ice in the Avs' game against the Bruins, Taylor Hall's shoulder collided with his face.

Video of the play shows MacKinnon's stick ended up wacking him in the nose ... 'causing him to bleed everywhere.

Somehow, MacKinnon got up and skated off the ice under his own power.

Colorado will miss the star while he's out ... he's been one of the best players in the league this season, tallying nine goals and 34 assists in 31 games.