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Celtics' fourth quarter woes were foretold earlier in the season

There has been no consistency in Boston's late-game defense this year.
May 7, 2025; Boston, Massachusetts, USA; Boston Celtics center Kristaps Porzingis (8) warms up before the start of game two of the second round for the 2025 NBA Playoffs against the New York Knicks at TD Garden. Mandatory Credit: David Butler II-Imagn Images
May 7, 2025; Boston, Massachusetts, USA; Boston Celtics center Kristaps Porzingis (8) warms up before the start of game two of the second round for the 2025 NBA Playoffs against the New York Knicks at TD Garden. Mandatory Credit: David Butler II-Imagn Images | David Butler II-Imagn Images

This morning, I saw a Bluesky post that seemed extremely incisive — as best I know what that word means. From the All-Star break until March 14th, the Boston Celtics had a 133.9 defensive rating in the fourth quarter, or the worst mark in the league.

So I decided to look up the Boston Celtics’ defensive rating from the All Star Break to the end of the regular season. Surely, the trend would keep up, and surely, the number would be awful.

Celtics fourth quarter defense after All-Star break was just okay

It was really, extremely fine. Arguably it was as fine as it could be. The Celtics fourth quarter defense rating was No. 16 in the league, per NBA stats, at 115.0.

Wait, what? How do you go from worst in the league to directly in the middle of the league in a month?

If your guess was by playing the best fourth quarter defense in the league, you were right. From March 14 to the end of the regular season, the Celtics were first in the league in defensive rating at 102.5.

That’s a 31.4 point difference. Sure, why not? Essentially, their fourth quarter defense has been extremely up and down all year.

This is immensely frustrating. I guess that’s just it, then. Boston has a switch. Sometimes, Boston just does the Boston thing and will, for certain stretches, just get bored. They’ll let teams back in. They’ll play with their meat, as Doc Rivers would say.

Well, maybe not. In going through the box scores of that stretch Keerthika made mention of on Bluesky, something stood out: Very little Kristaps. In fact, during that stretch, Kristaps Porziņģis only played 85 minutes and 7 seconds, if I did the math in my head right. The turnaround almost perfectly coincided with KP’s return to the regular rotation.

Well, right now Kristaps is dealing with an illness. Twice now the Knicks have come back in the fourth quarter to take win from the mouth of lose. That shaky 4th quarter defense is back again, and once again, KP’s presence isn’t there.

It’s hard to say if KP’s presence is the true difference there, or if it’s more a player further down the rotation not being ready for a more significant role, or it could be fatigue for certain players.

Whatever the case may be, Kristaps might be more important to the Celtics fourth quarters than we knew. Here’s hoping he can return soon.