Photo: Peter Baba

The Boston Celtics had their first meeting of the season with the Atlanta Hawks on Sunday night, but they did not face a familiar former teammate.

Kristaps Porzingis was unavailable for the matchup, Brian Robb of MassLive reported, as he remained sidelined with left Achilles tendinitis.

Porzingis, who was traded to Atlanta last summer in a three-team deal, missed his fourth straight game. He had also dealt with an illness earlier in the season and had appeared in just 17 of the Hawks’ first 43 games.

When he was on the floor, Porzingis had been effective, averaging 17.1 points, 5.1 rebounds and 1.3 blocks in 24.3 minutes per game. However, his frequent absences played a role in Atlanta’s uneven start.

After being viewed as a potential Eastern Conference contender following an active offseason, the Hawks entered the game stuck in play-in territory at 20-23.

Celtics star Jaylen Brown, who formed a close bond with Porzingis during their two seasons together in Boston, spoke about him during Saturday morning’s shootaround, per Souichi Terada of MassLive.

“He’s in my hometown,” Brown said, referring to Atlanta. “I remember we did a segment when he was in Boston and we came to Atlanta. I took him to American Deli and he went up to my high school as well.

“So I feel like that was kind of me helping him get introduced to the city. Hopefully he’s enjoyed it. Atlanta has many things to offer historically, so hopefully he’s having a great time. I haven’t communicated with him as much, but it’ll be great to see him tonight if he’s here.”