The Celtics have allowed their opponents to score 114.4 points per 100 possessions over the last four games. Only once in the last three seasons have they been worse defensively over a four-game stretch, and that was last March, when Kevin Garnett was out with a knee injury.

The Celtics have shot 52 percent or better in three of the four games, and yet they’ve lost all three.

“Usually, those are guaranteed wins,” head coach Doc Rivers said Tuesday. “Right now, they’re not. I really think it’s as simple as a lack of focus. And it’s on the defensive end right now.”

Schuhmann continues to put the odd change from a defensive-minded team into a “let’s-play-a-shootout team” into perspective.

At the All-Star break, the Celtics had the No. 1 defense in the league, allowing just 99.0 points per 100 possessions. At that point, their issues were on the offensive end of the floor, where they ranked 14th, even though they were the third best shooting team in the league. Turnovers were killing them and a lack of offensive rebounds wasn’t helping either.

But…

“Since the All-Star break, we’ve had a complete focus on taking care of the basketball,” [Doc Rivers] said. “And since the All-Star break, we’ve been pretty good at it.”

The Celtics are committing almost two fewer turnovers per 100 possessions since the break, down from 16.7 to 14.8. Their offensive rebounding is still bad, but they’re getting a couple of more shots per game.

That’s why the defensive issues of the last week are so disappointing. The Celtics have improved on one end of the floor, but regressed on the other. A suffocating defense has been their calling card for the last three years, and now they’re losing their identity.

The defense lately has been atrocious, but I’m not too surprised.  From one night to the next, you never know what you’ll get from these guys.