Things went from bad to worse for the Celtics late in the fourth quarter of Game 4. 

With just minutes remaining in the final frame, the Knicks had recaptured all of the momentum and were on the verge of closing out the victory on their homecourt to establish a commanding 3-1 series lead. 

Coming out of a timeout, power forward Jayson Tatum went down with a non-contact lower-body injury while diving for a loose ball in the open court. 

As OG Anunoby broke free for a huge fastbreak slam, Tatum remained down in the backcourt and was rolling around in an immense amount of pain before calling the Celtics’ final timeout on his own.

The All-Star forward was very emotional as he was immediately helped to the locker room by trainers.

He wouldn't return over the final few minutes, which saw the Knicks completely take things over to close out yet another come-from-behind victory.

Celtics head coach Joe Mazzulla didn't have an update on Tatum's status postgame, but he said he will undergo an MRI on Tuesday.

"I got back there and talked to the medical staff, they told me it's a lower-body injury," he said. "The fact that he had to be carried off, he's the type of guy that he usually gets right up. He didn't, we'll know tomorrow exactly what it is, but it definitely is tough to watch."

Prior to the injury, Tatum was putting together a tremendous showing — leading all scorers with 42 points on 16-of-28 shooting from the field and 7-of-16 from behind the arc.

"I never want to see a player get hurt," Knicks head coach Tom Thibodeau said. "He's been a great player and he's a great guy too, so I hope it's not a serious injury."

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