But with the league insisting the fixture proceed, the coach and affected players will not be involved as they seek to complete their recoveries and clear any remaining health protocols before returning to the court.
For Shamir, in particular, the virus has taken its toll. The 46-year-old Israeli, in his third season with the club, was "wiped out" for 10 days after contracting the virus, an ordeal that left Walsh shaken.
"There was definitely a moment when I was really scared for Dan," Walsh told Newstalk ZB's D'Arcy Waldegrave.
"You just don't know how this is going to affect you, and I think that's the scary part.
"We've had guys in our playing group who have had basically no symptoms, some of our staff and family members have had no symptoms, and then you have Dan who's been wiped out for 10 days.
"He's had a very difficult time and a really high fever for a long time. He's on the mend now and we're hoping that recovery continues. Even though he'll be out of isolation by Saturday, I think there's little chance that he's on the bench. Definitely not the head coach."
Walsh said Shamir's extended high-grade fever saw his temperature climb to 39.5 degrees and put paid to any plans he might have had of returning for Saturday's game.
"The toll that takes on your body, having that for seven, eight days in a row, along with the aches and the sweats and everything that comes with that, it's really just wiped him out from an energy standpoint and from a mental standpoint," Walsh said.
Assistant coach Mody Maor will be taking the reins against South East Melbourne, while the Breakers will also be missing another staff member who Walsh said was "hit really hard" and had to be hospitalised for observation.
But Walsh - whose own bout of Covid saw him endure a rough 36 hours - was forgiving of the Australian NBL for refusing to postpone Saturday night's game.
"If I take off my Breakers ownership hat and I look at it from a league perspective, it makes a lot of sense," Walsh said. "As much as I would have loved to get some sympathy, just based on what we've gone through the last two years, it's a precedent that the league had to set - that you can't cancel games just based on a few guys being out and a coach being out.
"We'll be missing two of our key rotations guys, two guys we had anticipated starting for us. It's unfortunate - especially given the fact that we're on the road for a second season in a row - that we're not totally healthy. But it's better now than in two weeks, and better that it affected only two guys instead of the whole roster."
