After watching the Celtics rampage their way to an NBA championship, two of Boston’s Atlantic Division rivals beefed up their roster with bold offseason moves.

The C’s will get their first look at one of those challengers Saturday night when the Philadelphia 76ers visit TD Garden for a preseason matchup.

The Sixers added nine-time All-Star Paul George to a talented core led by 2023 NBA MVP Joel Embiid and budding star point guard Tyrese Maxey.

“I think it’s exciting,” Celtics guard Derrick White said Thursday. “That’s the great thing about this league is every year, teams get better every year. You’ve got to improve and you’ve got to find new ways to win. So, they obviously made some new changes and they’re going to be better this year, and it’s going to be a lot of fun.”

Health is a major question mark with Philly’s newly assembled big three, as Embiid and George both have lengthy injury histories. Embiid (knee) did not travel with the team ahead of Friday’s preseason matchup with the Minnesota Timberwolves, putting his status for Saturday’s game at TD Garden in question. It’s also unclear whether George will play against Boston on the second night of a 76ers back-to-back.

In all likelihood, the Celtics won’t see the Sixers at full strength until their first regular-season matchup, which isn’t until Christmas Day.

Boston’s other reloaded rival is the New York Knicks, who, after finishing second in the Eastern Conference standings last season, overhauled their starting lineup with blockbuster trades for defensive stalwart Mikal Bridges and smooth-shooting center Karl-Anthony Towns. Boston will open the regular season with a home game against New York on Oct. 22.

Asked whether he sees opponents attempting to replicate the Celtics’ championship formula, White replied: “Yeah, for sure.”

“It’s always been like that since the beginning of basketball,” he said. “Teams see what works, and they try to duplicate it and try to find their own way of making it better. So I feel like that’s that’s how it is in basketball, and that’s why every year it’s more and more challenging.”

The Celtics won the East by a staggering 14 games last season. They should face a tougher road this season as they look to become the first NBA team since 2018 to win back-to-back champions. The last five title-winning clubs failed to even reach the conference finals the following season.

Saturday night’s game (8 p.m. ET) will be the Celtics’ first on Causeway Street since Game 5 of the NBA Finals. They’ll also host the Toronto Raptors at 7 p.m. ET on Sunday.

“I haven’t been back since, really, the parade, so looking forward to being back in the Garden again,” White said. “And I was telling some of my people, I was like, usually the preseason, everywhere else, the energy’s kind of down in the arena. But in Boston, it’s always up. So I don’t think it’s going to be any different this year. It’s probably going to be even more. So I’m excited for it.”

High praise for Hauser

There aren’t many 3-point shooters that Payton Pritchard would take over fellow Celtics reserve Sam Hauser.

“I think Sam is one of the best — if not the best shooter, up there with the best in the league,” Pritchard said.

Hauser’s beyond-the-arc shooting last season ranked among the best in the NBA — and helped him land a four-year, $45 million contract after coming into the league as an undrafted rookie. Seventy-players players attempted at least five threes per game during the 2023-24 campaign, and just six made them at a higher clip than Hauser’s 42.4%.

Pritchard and Hauser both were vital depth pieces for last year’s championship squad, and they’ll be two of head coach Joe Mazzulla’s top off-the-bench options again this season.

“That’s like my brother,” Pritchard said. “… I put in on the ground a little bit more, so our skill sets kind of match. He’s moving without the ball a lot more. Especially from playing together, I can find him. … We’re just always expanding our games together.”

The pair went a combined 5-for-6 from 3-point range in last Sunday’s exhibition win over Denver in Abu Dhabi, with Hauser also grabbing eight rebounds in 16 minutes. Hauser’s shot was shaky in Boston’s preseason opener last Friday (2 of 8 from three), but Pritchard went 6-for-12 from deep en route to a game-high 21 points.

“Those two guys are just rock solid, and they work every single day,” Mazzulla told reporters in Abu Dhabi after Sunday’s game. “They work at the same basket. They’ve built a great relationship with each other. They both have an understanding of how to impact the game, both on offense and defense, and they’re reliable.

“You know exactly what you’re getting from them every single night from those guys on both ends of the floor. So it’s a compliment to our player development staff that has worked with them over the years, and it’s a compliment to them and the work ethic that they have.”

Off the rim

Mazzulla said the Celtics didn’t pick up any new injuries during their Abu Dhabi trip. “Came back healthy, got some good days of practice and get a chance to compete [Saturday],” the coach said. … Newly re-signed guard Jay Scrubb sported a large wrap/brace on his surgically repaired right knee after practice. It’s unclear whether Scrubb, who practiced Thursday for the first time since tearing his ACL last October, will see any playing time in any of Boston’s three remaining preseason games. … After each practice, White competes in unorthodox shooting competitions with a handful of Celtics assistants. Thursday’s involved walking toward the basket while balancing the ball on a crayon-shaped handheld pad, then shooting with the other hand once the ball fell. “Anybody can throw an idea out there,” White said. “We need as many ideas as we can get, honestly. But [assistant coach] Ross [McMains] is probably the most creative. He came with that one today. [We] just kind of figure it out. Usually at the end of my shooting and we just try to think of something real quick.”