Smart, already dealing with an abdomen contusion that forced him out of Sunday's game in New York, did not practice Tuesday due to the illness and he didn't improve overnight.
"He's sick. He was feeling worse last night, feeling worse this morning, so he won't play tonight," Celtics coach Brad Stevens said at shootaround. "He didn't do anything. Didn't come in this morning."
And his abdomen injury?
"No word on his oblique," said Stevens. "But I'm sure it's uncomfortable to be sick with that."
Stevens noted that 2-way guard Tremont Waters, who could provide emergency depth if needed, was still with the Maine Red Claws as of Wednesday morning.
Asked about Fall, who has been rehabbing at the Celtics' facility in recent days, Stevens noted, "He's good. Getting better. Doesn't love the snow. But he's getting better."
The Celtics host a Miami team coming off an overtime win over the Toronto Raptors last night.
"[Erik Spoelstra is] a really good coach. Very creative. And they play really hard," said Stevens. "I think that they probably play as hard consistently as anybody in the league. And then I think they are just really creative in opening up the floor for their guys. They have done a great job with a couple of these young players.
"And they have excellent shooting. I don't know what their shooting numbers were last year, I haven't gone back and looked at it, but right now they are second in the league in 3-point percentage and they have a few guys that, every time it leaves their hands it looks like it's going in. If you don't provide the right amount of pressure, if you don't get into their air space, you're in trouble, but they can put a team on the floor like they did last night with [former Celtics big man] Kelly [Olynyk] on the floor at the 5 where everybody can shoot the ball, and shoot it at a high clip."
Don't miss NBC Sports Boston's coverage of Celtics-Heat, which tips off Wednesday at 7 p.m. with Celtics Pregame Live, and then Tommy & Mike have the call at 7:30 p.m. You can also stream the game on the MyTeams App.
Celtics rule banged up Marcus Smart out for game vs. Miami Heat originally appeared on NBC Sports Boston