SAN FRANCISCO — As RJ Barrett emerged from a trainer’s room inside Chase Center on Thursday morning, it wasn’t a pretty sight.

Barrett was in a walking boot, still limping two days after he sprained his left ankle with 18 seconds left in a blowout loss in Denver on Tuesday.

Barrett said hello to reporters but didn’t talk about the injury that kept him out of Thursday’s 116-114 win over the powerhouse Warriors.

The way he was laboring, it did not seem like Barrett would be back for the trip’s finale in Portland on Sunday afternoon. Knicks coach Tom Thibodeau said Barrett was “day-to-day’’ and was short when discussing the topic.

Who could blame him? His curious habit of leaving key players late in blowouts came back to haunt him. The Knicks were trailing by 16 points when Barrett took a bad step. It’s a shame since Barrett had been going strong since the start of the new year.

The good news is this gave Cam Reddish, who played the previous two games on this trip because of injuries to teammates, an opportunity. Reddish scored 12 points on 4-for-8 shooting in 19 minutes of action against the Warriors.

Reddish had not looked particulary sharp entering play Thursday, missing badly on an array of 3-point shots and turning the ball over. In the 29 minutes he played in the previous two contests against Utah and Denver, Reddish was a minus-37 and shot 0-for-4 from 3. Atlanta traded Reddish because the former Duke star wanted more playing time.

Rookie SG Quentin Grimes, who missed the last two games with a sore knee, was back for Thursday’s game and started in Barrett’s place. He scored six points and grabbed three rebounds in 31 minutes.

The sophomore jinx has officially struck Immanuel Quickley.

Since being shunned from the Rising Stars Challenge, Quickley has played four games and shot 7 of 30 overall, 2 of 17 from 3-point range. With so much emphasis on Julius Randle’s decline, Quickley’s demise is another reason for the team’s downfall. Quickley scored five points in 16 minutes against Golden State.

The Knicks finished shootaround with one hour left before the trade deadline, which could’ve been awkward if a deal had been hatched.

“You just got to stay focused,’’ Thibodeau said. “It’s all part of the league. You lock into what you got to do. All the trades that get talked about, very few get done.’’

The Warriors were playing the second night of a back-to-back after getting routed in Utah Wednesday, 111-85, snapping their nine-game winning streak.