The Celtics’ injuries are beginning to stack up.

Boston ruled out three players for its Friday night matchup against the Brooklyn Nets at TD Garden: wing Jaylen Brown and centers Luke Kornet and Kristaps Porzingis.

It was the fourth consecutive DNP for Brown, who’s dealing with a hip flexor straight, and the first of the season for Kornet, who exited Wednesday’s loss to Golden State with hamstring tightness.

Celtics coach Joe Mazzulla had no update on either during his pregame news conference, saying both were “day to day, like the rest of us.”

Porzingis has yet to make his season debut as he works his way back from offseason leg surgery. He’s targeting a December return.

Boston’s injuries have forced Mazzulla to dig deeper into his bench, leading to increased roles for players like Jordan Walsh and Neemias Queta, neither of whom saw meaningful playing time during last season’s playoff run.

“I think any time a person’s hurt and you’re a guy that’s kind of in the rotation, out of the rotation, kind of on the fringe, it’s always a big opportunity to show what you can do and step in and play in a role and try to fill the void,” backup wing Sam Hauser said after Friday morning’s shootaround. “I’ve been in that position before, and I’m always rooting for those guys to help us out in any way possible.

“It’s nice that we do have familiar faces around. You can kind of just throw them in and they’re going to know what they’re going to do. That’s pretty cool.”

Queta, a G League player for much of last season, has impressed of late. The 25-year-old big man has been one of the NBA’s most efficient offensive rebounders and led the Celtics in plus/minus in each of his first two career starts.

“For him, I think it started in Summer League,” Mazzulla said. “Just the staff preparing him for what he needed to get better at most, which is just our defensive coverages and having an understanding of tendencies and things that we need to go to game in, game out. So I think that’s his biggest area of growth — just earning the trust of people around him to where he can execute different coverages.”

Queta did not get the nod against Brooklyn, however. Mazzulla shuffled his starting five, inserting Xavier Tillman alongside Derrick White, Jrue Holiday, Jayson Tatum and Al Horford. It was Tillman’s third start in a Celtics uniform and his first since last season.

Tillman had seen his role shrink before Friday’s promotion. He played just 12 total minutes over the previous four games and was a DNP-coach’s decision in two of them, including Wednesday’s loss to the Warriors.

Better than last year?

The 2023-24 Celtics were historically dominant during their run to an NBA title, finishing with an 80-21 record and one of the best net ratings in league history.

Holiday believes Boston’s current squad — which returned nearly its entire championship-winning roster — has the potential to be even better.

“I definitely think we can be, and I think it’s because of the chemistry we’ve built,” the veteran guard said in an interview with FanDuel TV’s “Run It Back.” “I think when you go through something like a season last year where, again, it was my first year (in Boston), but you go through a season like last year and you win and you do it together and everybody’s not only on the same page, but everybody messes with each other, I think it means a lot.

“I think the care for each other is there more, the intent. I think people wanting to do what’s best not only for yourself, but for the team, carries over into this next year. So, I think we’re a lot better — and we don’t even have (Porzingis) yet.”

Advice for Scheierman

While the Celtics hosted the Nets, their G League affiliates squared off on Long Island in the season opener for both farm clubs.

Among the players suiting up for Maine was Celtics first-round draft pick Baylor Scheierman. The rookie wing will rotate between the NBA and G League as Boston looks to get him playing time that isn’t available with the big club.

Hauser spent time in the G League before becoming a core part of the Celtics’ rotation, and he helped mentor Scheierman during the latter’s first NBA training camp. His advice to the rookie: “Be yourself, let it fly and have fun.”

“It’s always fun when you get to play,” Hauser said. “And considering our roster and everybody being back, opportunities are going to be limited for him here, so it’s probably good for him to go get game-like reps in Maine and play basketball. That’s the best part about it.”

The Celtics hope minutes in the minors will help Scheierman rediscover his shot. A prolific 3-point shooter during his five-year college career at Creighton and South Dakota State, the 24-year-old shot just 16.7% from the floor and 17.6% from three during the preseason. He’s only played in blowouts since the regular season began, going 1-for-6 and 0-for-4 from deep across three appearances.

One of Boston’s three two-way players did not join Maine for its season opener. Drew Peterson remained with the Celtics to provide additional depth with Brown, Porzingis and Kornet unavailable.

Off the rim

Hauser missed three games with lower back pain before returning to action Wednesday. Is it still causing him issues? “Here and there,” he said. “We’re managing it, though.” … Tatum entered Friday’s game with three technical fouls on the season. Sixteen triggers an automatic suspension. Is Mazzulla concerned? “No, he’ll be OK,” said the coach, who noted he’s “not far behind” with one technical. “I’m not worried about that at all.”