The message came from the star goalkeeper's NHL club New Jersey Devils on Friday.
The club writes that an X-ray indicates a stretched ligament in the knee and that he will be out for approximately four to six weeks.
Four Nations begins in just under three weeks.
We will give it a few days, we have had contact with "Markan" today, but we see that participation is highly unlikely, says Hallam after the message.
Is he disappointed?
Of course, both for what he does in Devils now, but also for Four Nations. But unfortunately, this is part of the game for both teams and individuals, says Hallam.
Injured in collision
Markström injured himself after a collision in New Jersey's match against Boston on Thursday night.
For Tre Kronor, the message is a nightmare since Ottawa's goalkeeper Linus Ullmark is also out due to injury and an uncertain card ahead of Four Nations, which takes place on 13-21 February.
We are following his situation and he himself is very goal-oriented and working hard to be playable. So we'll see what happens in the next 10-14 days, says Hallam.
Filip Gustavsson, Minnesota, is the third goalkeeper who has been selected for Tre Kronor.
Nightmare scenario
With two goalkeepers injured, it looks like a nightmare scenario for Sweden.
It's the headline writers' way of looking at it. This is part of the game. You rarely get perfect conditions, I'm glad we have the breadth we have on all positions. We will have a good goalkeeper when we play the first match, says Hallam.
Samuel Ersson, Philadelphia, can be a possible replacement for Markström.
Sweden will meet Canada, Finland, and the USA in a tournament where only NHL players participate and which is the most star-studded since the World Championship 2016.
