CLEVELAND — A bad day for the Knicks got worse late in the first half when Kristaps Porzingis turned his right ankle and limped off the court.

Porzingis never returned. A sprained ankle ended his night and the game ended with another Knicks loss, as they fell to the Cavaliers, 119-104, on Thursday night.

The Knicks’ second-year big man hurt his ankle after stepping on teammate Willy Hernangomez’s foot. Porzingis left in a walking boot and said he will undergo further tests Friday, Jeff Hornacek called it a “mild” sprain. Porzingis said he doesn’t know how long he’ll be out.

“It didn’t feel too good,” he said. “I was thinking about coming back. It was a little too much. It just got bigger all around. Hopefully [it’s] not too bad. We’ll see [Friday].’’

He left with eight points in 16 minutes.

It’s been a rough go for Porzingis, who has been in and out of the lineup with an Achilles issue and a stomach virus. “It happens,” he said. “Maybe it’s something I need to get my mind off a little bit. Maybe that’s why it happens or things like that. It happens, but I always take it as a challenge. I always think about the next step of coming back and coming back better.”

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The Knicks hoped for a fresh start after the All-Star break, and maybe some new blood. But team president Phil Jackson made no moves before Thursday’s trade deadline. As a result, the Knicks looked exactly the same as they did before the break.

With Charles Oakley sitting in the front row next to Cavaliers owner Dan Gilbert, the Knicks (23-35) fell behind by 21 in the first half and lost for the eighth time in the last 10 games. They have lost 22 of 29 and are a season-worst 12 games under .500.

LeBron James recorded a triple-double with 18 points, 15 assists and 13 rebounds and had a resounding block of a dunk attempt by Courtney Lee. Kyrie Irving scored 23.

After the Knicks got within 97-89 to start the fourth quarter, James led the Cavaliers on a 12-2 run. He was responsible for all 12 points, with two baskets and three assists. “LeBron in that fourth quarter really picked us apart,” Hornacek said.

Lee, who returned from a stomach virus that kept him out of the last two practices, shot 10-for-15 and scored 25 points. Carmelo Anthony added 20 but missed 16 of 25 shots. Derrick Rose, the closest Knick to being moved, had 13 points.

Given that the Knicks stood pat, it seemed to signal that they hope to make a playoff push, but they’re five games out of the last playoff spot with 24 to play. The Knicks host Philadelphia tomorrow, beginning a stretch in which they will play eight of 11 games against teams currently below .500. If they can’t turn it around, they’ll be headed for the draft lottery.

The Cavs scored 61 points in the final 18:44 of the first half and led 69-51 at the break. The lead reached 21 when Channing Frye drilled a three-pointer to open the third quarter. The Knicks stormed back to get within eight after holding the Cavs to 18 points in the third, but then James took control.