BOSTON – The good news is that Bruins defenseman Matt Grzelcyk has been released from the hospital and has begun his recovery from a nasty head hit suffered in Wednesday night’s Game 2 loss. The bad news is that the Bruins puck-moving D-man is in the concussion protocol, per B’s head coach Bruce Cassidy, and isn’t going to be travelling with the rest of the team to St. Louis on Thursday afternoon ahead of Games 3 and 4.

“When we have a further update, we’ll give it you,” said Cassidy, who termed Grzelcyk day-to-day for right now.

Grzelcyk was the victim of a nasty head shot off the glass above the boards courtesy of Blues forward Oskar Sundqvist in the closing minutes of the first period in Wednesday night’s 3-2 overtime loss, and obviously never returned to the game while being sent to the hospital with a concussion.

Sundqvist is facing a phone hearing with the NHL Department of Player Safety on Thursday afternoon at 4 p.m. for the offending hit-from-behind and head shot where he was initially charged with a minor boarding penalty on the play.

Given the violence of the head hit on a play where Grzelcyk wasn’t eligible to be checked with his back turned to the play and the fact that there’s also a resulting injury, one would suspect that Sundqvist is going to face at least a one-game suspension for the dangerous play. That doesn’t really do the Bruins any good now, however, as they’ll be missing one of their fastest skaters and best puck-movers from the lineup, and it would be a surprise if he plays in either of the next couple of games in St. Louis while waiting for the fog to clear in concussion protocol.

Clearly the absence of Grzelcyk slowed down the Bruins attack a bit in Game 2, and forced the B’s into playing Zdeno Chara, Charlie McAvoy, Torey Krug and Brandon Carlo big minutes that played into the Bruins simply running out of gas in the overtime loss.

Click here to download the new MyTeams App by NBC Sports! Receive comprehensive coverage of your teams and stream the Celtics easily on your device.