CELTICS NOTEBOOK: Jaylen Brown returns with an impressive performance

After missing three games with a sore back, the Celtics guard scores 21 points off the bench in a 128-100 win over the New York Knicks Thursday nighit.

BOSTON – He had struggled through the first quarter of this season, then suffered a back injury on a nasty fall on Nov. 24.

Jaylen Brown’s third season did not exactly get off to the smoothest start, but when he returned from a three-game absence in a new role Thursday night, the Celtics guard took a step in the right direction.

Brown, coming off the bench in a regular-season game for the first time since the end of his rookie season in 2016-17, had a season-high 21 points in 25 minutes to help the Celtics win their fourth straight game, 128-100, over the New York Knicks at the TD Garden.

After sitting out wins over the New Orleans Pelicans, Cleveland Cavaliers and Minnesota Timberwolves with a sore back, Brown was aggressive as soon as he reported into the game in the first quarter.

He took the ball to the basket and was fouled on his first two possessions and wound up attempting a season-high nine foul shots, hitting seven. Brown was 7 for 10 from the field in his first game in nearly two weeks.

“It held up pretty good,’’ said Brown of his back. “It feels better when you get a win.’’

Coach Brad Stevens inserted Marcus Smart into Brown’s starting spot and has stayed with him as the Celtics put together the winning streak. Brown, who started 70 games last season and the first 19 he appeared in his season, has no problem coming off the bench.

“No different for me,’’ he said. “Basketball is basketball whether it’s coming off the bench or walking out of the stands. It’s all basketball.’’

The aggressiveness was evident for Brown, who had lacked that during the first quarter of the season.

“Be aggressive, do what I do best,’’ said Brown. “Things opened up a little bit and I continued to be aggressive and I felt like I put myself in a good spot.’’

Said Stevens: “I thought he was really good. I thought he played with great pace and purpose and made really good decisions. I didn’t think anything was forced, which sometimes when you come off the bench, that’s one of the things you try to catch up to the game quickly. He just played the right way. We needed it.’’

Williams excused: The Celtics assigned rookie Robert Williams to the Maine Red Claws to play in Thursday night’s game against the Oklahoma City Blue, but that didn’t happen.

Williams was excused from play because of a personal reason. Williams had appeared in two previous games with the Red Claws, averaging 13.5 points, nine rebounds and 2.5 blocks.

“He is excused by all of us to attend to a personal matter,’’ said Stevens before the win over the Knicks.

Baynes injured: Center Aron Baynes left the game with less than two minutes in the first quarter with a sprained left ankle and did not return. He was injured on a play underneath the basket.

“In typical Baynes fashion, he said he’ll do three-on-three drills tomorrow after he does full-court sprints and then runs a marathon and then he’ll get ready for the flight and then he’ll play on Saturday (in Chicago),’’ joked Stevens. “But I don’t know if our doctors agree with that. Baynes thinks he can play through anything.’’

On the road: The Celtics play in Chicago against the Bulls on Saturday night, then have six of the next eight games through Christmas Day at the Garden. … The Celtics faced the Knicks after having four consecutive days off, giving Stevens a chance to hold back-to-back practices. Asked if the break in the schedule came at a good time, Stevens cracked, “If you have kids that are 13 and 9, all gaps are well-timed breaks, whether you’re 7-20 or 20-7. It doesn’t matter.’’

Jim Fenton may be reached at jfenton@enterprisenews.com. Follow him on Twitter at @JFenton_ent.