The Boston Celtics have posted a 21-player Celtics training camp roster ahead of Tuesday’s Sept. 29 open at the Auerbach Center, giving coach Joe Mazzulla three weeks of practices and four preseason games to cut the group to a 15-man Opening Night roster before the Oct. 20 visit to Detroit.
According to NESN’s roster breakdown, Boston enters camp with 14 players on standard contracts, two on two-ways, and five Exhibit 10 invitees competing for the last standard and two-way spots. The timeline is firm: roster decisions are due by Oct. 19, with preseason games scheduled between Oct. 8 and Oct. 16.
Celtics training camp roster: contracts and invitees
The standard core includes Jayson Tatum, Derrick White, Payton Pritchard, Sam Hauser, Neemias Queta, Baylor Scheierman, Jordan Walsh, Hugo Gonzalez, Luka Garza, Ron Harper Jr., and rookies such as Chris Cenac Jr., plus high-profile additions Paul George, Mitchell Robinson, and Mike Conley. Dillon Mitchell and Amari Williams hold two-way deals. Devin Carter, Tucker DeVries, Hayden Gray, Gabe McGlothan, and Milos Uzan signed training-camp contracts and will battle for Maine Celtics pathways if they do not stick in Boston.
Mazzulla’s staff will use those Exhibit 10 battles to stress-test wing depth after an offseason that reshaped the supporting cast around Tatum.
New faces reshape Boston’s depth chart
NBA.com’s 2026-27 season preview frames the winter as a new era after Jaylen Brown’s departure to Philadelphia, with George and Robinson arriving to reinforce the frontcourt and Conley adding veteran point-guard minutes. Tatum’s health after last season’s Achilles recovery remains the central storyline, while Robinson’s minutes will be managed as he assimilates into Boston’s scheme. White’s three-point bounce-back is another early-camp priority after he shot 32.7% from deep in the regular season.
Projected rotations already debate whether Pritchard starts or comes off the bench, whether Queta or Robinson anchors the backup five, and how much Gonzalez expands his Year-2 role after logging more than 1,000 minutes as a rookie.
Path to Opening Night vs. the Pistons
Boston opens the regular season at Detroit on Oct. 20, a rematch series that produced four one-possession finishes last season. Before tip-off, four preseason games will decide which of the five camp invitees earn roster or two-way space and which land with the Maine Celtics. For a franchise chasing a 13th straight playoff berth, the Celtics’ preseason history shows how early cuts and minutes can foreshadow the November rotation.
What Boston fans should watch this week
Camp opens Tuesday with conditioning, defensive pairings, and early looks at George alongside Tatum and White. Watch for how Mazzulla mixes Conley with Pritchard, whether Robinson shares the floor with Queta in short bursts, and which Exhibit 10 wings earn second-unit run. Local sports coverage this week also tracks the Bruins’ preseason wrap and the Patriots’ Week 3 injury picture as Boston’s fall calendar fills out.
Sources: NESN training camp roster report; NBA.com 2026-27 Celtics season preview.