A total of 21 players are set to attend training camp with the Celtics, the team confirmed this week.

Boston, which opens camp on Tuesday, updated its official roster to include the five players signed to training camp tryout contracts, plus the 14 on standard contracts and two on two-way deals.

Those five roster hopefuls are:

— Guard Devin Carter, a 2024 lottery pick (13th overall) who previously starred at Providence College. A former Big East Player of the Year, Carter signed an Exhibit-10 contract with Boston after being traded to and then waived by the Atlanta Hawks earlier this month. The 24-year-old averaged 8.9 points and 2.7 assists in 38 games (12 starts) for Sacramento last season, shooting 41.4% from the field and 26.3% from 3-point range.

— Guard Milos Uzan, an undrafted rookie who played alongside Celtics first-round draft pick Chris Cenac Jr. at Houston. Uzan led the Celtics’ Summer League team in minutes played, totaling 20 assists and seven turnovers in five games while making 36.8% of his 3-pointers. His college coach, Kelvin Sampson, called Uzan “an NBA player” and “a winner” who is “not flashy, but he’s highly efficient.”

— Wing Tucker DeVries, another UDFA who played for Boston’s Summer League outfit. DeVries was a two-time Missouri Valley Conference Player of the Year at Drake before transferring to West Virginia and then to Indiana. He scored in double figures in three of his four appearances for the Summer C’s, though he shot just 38.7% from the field and totaled four rebounds in 77 minutes.

— Guard Hayden Gray, who’s back after playing for the Celtics in last year’s Summer League, attending camp with Boston last fall and spending nearly all of the 2025-26 season with the G League Maine Celtics. Utah signed him in April, and he appeared in one game for the tanking Jazz. Steals are Gray’s specialty; he led the nation in that stat as a senior at UC-San Diego in 2024-25 and ranked second among all G Leaguers last season.

— Forward Gabe McGlothan, who’s spent time with Denver’s and Indiana’s affiliates since going undrafted in 2024. He suffered multiple rib fractures in a G League game in February and missed the rest of the season.

Carter, Uzan, DeVries, Gray and McGlothan will compete for the Celtics’ one open 15-man roster spot and one vacant two-way slot. Boston is not required to fill either; it chose to enter each of the last several seasons with only 14 players on standard contracts.

The Celtics currently signed to standard deals are guards Derrick White, Payton Pritchard and Mike Conley; wings Jayson Tatum, Paul George, Sam Hauser, Baylor Scheierman, Jordan Walsh, Hugo Gonzalez and Ron Harper Jr.; and bigs Neemias Queta, Mitchell Robinson, Luka Garza and Cenac.

George, Robinson, Conley and Cenac were offseason additions.

Second-year center Amari Williams and rookie wing Dillon Mitchell are signed to two-way contracts.

Players on two-ways are allowed to be active for up to 50 NBA games, and their contracts can be converted to standard NBA deals at any time before the end of the regular season. (Last season, Harper attended Celtics camp on an Exhibit-10, played most of the season on a two-way and then signed a full-time NBA deal before the playoffs.)

The Celtics will hold their 2026-27 media day on Monday, with their first official practice scheduled for the following day. They will open their four-game preseason schedule on Thursday, Oct. 8 with a road game against the Cleveland Cavaliers.

Boston then will host the Philadelphia 76ers on Oct. 10 and the Charlotte Hornets on Oct. 14 before closing its exhibition slate at Philadelphia on Oct. 16. Head coach Joe Mazzulla’s squad will open the NBA’s regular season in Detroit against the Pistons at 3 p.m. ET on Tuesday, Oct. 20.