The 27-year-old was playing in his second preseason contest since being cleared for game action when he caught a rut as he was taking a hit in the corner during the first period. Krug attempted to play following the injury, but after a few minutes retreated to the dressing room.
"I wasn't in too much pain right away, probably the adrenaline of the game and things like that," said Krug. "But as the period went on, just wasn't able to finish and got closer to the end and decided to go to the room and get some attention from the medical staff. They obviously did their job and started to realize something was wrong."
This is the second consecutive season that Krug was injured in the preseason. Last fall, the defenseman suffered a broken jaw during the second preseason game, causing him to miss the opener.
This time around, patience will once again be required.
"Hopefully everything feels good by then and I can start to get going on the ice," said Krug. "It would be ignorant to think after three weeks off the ice that you could jump in and go ahead and play and jump in full-go.
"So there's probably going to be a period of time where you ramp things up. It's just very unfortunate. We'll see where it stands after that."
In the interim, coach Bruce Cassidy must decide how to fill the hole. It appears that Matt Grzelcyk has the early edge, but a lower-body injury has put his availability for Wednesday night in question. Should he not be ready, Cassidy could turn to rookie Urho Vaakanainen or veteran Steven Kampfer.
"Right now, Vaakanainen - three lefts, three rights is kind of the way we're looking," said Cassidy. "But we'll make that decision once we hear about Grizz. Vaakanainen's been very good, so has Kampfer. So whatever direction we go we feel comfortable."