Their head coach will not be replaced if he does not commit a violation.

he was suspended for this coming season
https://www.cnbc.com/2022/09/23/boston-celtics-suspend-head-coach-ime-udoka-for-upcoming-season.html

So let the assistant coach handle the job, and let's see if he can still make Celtics a great team.

"It's not about carrying on from one person," Mazzulla said during the team's media day here in the Boston suburbs. "It's about carrying on the identity of our players. We had our struggles early last season, but at our best, we knew what our identity was. It was our defense, it was our buy-in from a defensive standpoint, and then it was sharing the ball and moving quickly on the offensive end.
"So as much as we can stick to the things we were great at last year, and then find areas to improve along the way, I think is the right way to go."

"Joe has been here. He knows the scheme, he knows the players, so it makes it a little bit more easier to adjust to a guy that's been here and knows you."