BOSTON — Celtics coach Joe Mazzulla stresses it frequently when it comes to the defensive side of the ball. A possession only ends in two ways: A defensive rebound or a turnover. So, it’s a non-negotiable and priority that the Celtics must rebound on every available possession.

But that’s been a struggle through the early parts of preseason. It happened again for stretches even though the Celtics blew out the Cavaliers on Sunday. The Cavs picked up 21 offensive rebounds as the C’s weren’t good enough on that end. That showed as Mazzulla subbed players out if they weren’t rebounding to find a five-man combination willing to crash the defensive glass.

“I don’t see five guys rebound,” Mazzulla said. “So then I go get five, and they rebound. It’s that simple. Doesn’t matter about wings,

See Full Page