Following the practice, Cassidy did not have further information on Krug's status heading into next week, when Boston will begin postseason play.
"He'll be out [Saturday] that much we know, and then from there, day-to-day," said Cassidy.
With Krug's skill set, he will not be easily replaced.
"Well, we're not going to be able to replace what he does," said Cassidy. "He's a special talent - power play, first pass, breakout, neutral zone transition, all of those things - so the onus will be on us to make sure we make the necessary reads in our breakout."
"And the power play, you know Johnny Liles has certainly been on there, Zee's done a good job, recently we've mixed him in. If Colin Miller draws into the lineup, he's been on it, so there are options there," said Cassidy.
"We're going to miss his ability to get us going on offense in a hurry. But having said that, we've got good puck movers back there and it's the way it is this time of year - you get an injury, it's next man up who's got to get in there, and play to his strengths without trying to be something that he's not, so that's what we'll ask of that position."
"Losing a guy like Torey's never easy," said Captain Zdeno Chara. "And he's obviously's been a big part of our team's specialty teams and obviously we don't know the status of the injury, but hopefully he's going to be back and on the ice soon."