The Celtics wrapped up an undefeated preseason Friday night, upsetting the Philadelphia 76ers in overtime while starting a lineup of G League players.
As Boston shifts its focus to Tuesday’s season opener in Detroit — a rare 3 p.m. weekday tipoff against Cade Cunningham and the Pistons — here are five things we learned about head coach Joe Mazzulla’s squad during its four-game exhibition slate:
Rotation outlook
Mazzulla is loath to reveal any details about his game plans, so the Celtics’ opening night starting lineup could be a unit we have yet to see in action. That was the case last year, when Mazzulla started four different lineups in the preseason and then a fifth in the opener (and a sixth two games later).
But here’s what we know right now: In the two games Boston’s starters played this preseason, Mazzulla went with the same top five: Derrick White, Jordan Walsh, Paul George, Jayson Tatum and Mitchell Robinson. He also had the same substitution pattern behind them: Payton Pritchard and Neemias Queta first, then Sam Hauser and Baylor Scheierman, then Hugo Gonzalez and Luka Garza. Those 11 made up the Celtics’ core rotation.
Again, knowing Mazzulla, it would not be surprising if this setup changed Tuesday afternoon. He could opt for Queta — who started 75 games last season and finished fourth in Most Improved Player voting — over Robinson, or swap any number of players into the Walsh spot.
That’s the starting job with the widest range of viable candidates; one could make a case for Pritchard, Scheierman, Hauser or Gonzalez. But Mazzulla, for what it’s worth, said he likes what Walsh brings in that role.
“Jordan continues to be really good at the start of games, guarding the team’s best player, getting off to a good start defensively,” Mazzulla said after Wednesday’s win over Charlotte. “(It’s) something he’s done well for us those last couple of games, and it’s a huge role for him that we’re going to need from him.”
If Walsh sticks, expect to see him defending Cunningham, Detroit’s All-NBA point guard, on Tuesday.
Regardless of how Mazzulla structures his (likely ever-evolving) rotation, the Celtics will be able to field an experienced second unit, which was not the case at this point last year. Queta, Pritchard, Hauser, Scheierman and Walsh all started 20-plus games in 2025-26, and Garza and Gonzalez both played in at least 69. Mike Conley’s in the mix, too, as a veteran leader/depth piece.
This preseason, Boston outscored opponents by 47 points with Queta on the floor, by 50 points with Hauser and by 54 points with Pritchard.
Boston Celtics center Neemias Queta blocks Charlotte Hornets forward Brandon Miller during Wednesday’s NBA preseason game. Matt Stone/Boston Herald)
Tatum looks healthy
Tatum’s numbers over his two preseason appearances: 21.0 points, 6.5 rebounds, 5.0 assists, 1.5 steals, 47.2% shooting, 38.9% on 3-pointers.
He played the entire first quarter in both games — scoring in double figures in both — and led all Celtics starters in minutes played (27 vs. Philadelphia; 29 vs. Charlotte). Had he not sat out the two fourth quarters, he likely would have come in right around his usual gameday average of 35 to 36 minutes.
Tatum had four turnovers in his second game and attempted just one free throw this preseason, so there’s a higher level for him to reach. But if you didn’t know he was entering his first full season since his Achilles surgery, you wouldn’t guess it from how he’s played thus far.
One unanswered question is whether the Celtics will manage Tatum’s workload (and George’s, and Robinson’s), particularly during their hectic early-season schedule. Boston has four back-to-backs in the opening month and will play 12 of its 16 November games on the road.
Turnover uptick
The Celtics have never boasted anything less than a top-tier defense under Mazzulla (second, second, fourth and fourth in defensive rating in the last four seasons), but those units never put much stock in forcing turnovers.
Even last season, Boston touted a plan to be more aggressive defensively but quickly abandoned it, ultimately finishing 28th in steals (7.1 per game) and 29th in opponent turnovers (12.4)
Will that change this year? The small sample of the preseason suggests it could.
Over the two games the starters played, Boston’s opponents committed a whopping 53 turnovers. The Sixers committed 18 on Friday — including 14 by Jaylen Brown, LeBron James, Tyrese Maxey and Joel Embiid — while nine different Celtics registered at least one steal.
Don’t discount the impact George and Robinson can have in this area. The two new Celtics ranked in the 89th and 95th percentile, respectively, for their position in steal rate last season.
“Defensively, they take things to another level,” Mazzulla said.
George struggled to find his shot during his two preseason outings (25.0%; 21.4% from three) but racked up seven steals. As a team, the Celtics ranked fourth in the NBA in steals per game.
Stock up: Hugo Gonzalez
One player who certainly did not struggle as a shooter this preseason was Gonzalez.
The second-year wing dramatically improved his 3-point field-goal percentage, going 11-for-20 from deep (55%) over four games. He also scored 15-plus points in three of those contests — including a team-high 21 in 20 minutes in Friday’s finale — after doing so just once in 74 appearances as a rookie.
Gonzalez stressed last week that his “first job is to be a great defender,” so scoring is far from his top priority in Year 2. But his confidence and visible improvement on the offensive end are very encouraging developments for Boston.
One game enough for Carter
We haven’t seen Devin Carter since he dropped 17 points in Boston’s preseason opener. He missed subsequent practices and the next two games with an illness, then was inactive again Friday night in Philly.
But the Celtics saw enough from the 2024 lottery pick to want to continue working with him. The team reportedly converted Carter’s Exhibit 10 tryout deal to a two-way contract, allowing him to split time between the C’s and their G League affiliate in Maine this season.
Carter starred at Providence College before playing two nondescript seasons with the Sacramento Kings. At 24, he’s a young, high-upside addition to the Celtics’ veteran-laden backcourt.
Boston will hope he can follow a similar path to Queta, who was waived by the Kings before finding a home with the Celtics.