Celtics Sign Amari Williams and Ron Harper Jr. to Round Out Camp Roster

The Celtics signed Amari Williams and Ron Harper Jr. to round out what should be the 21 players who will attend training camp late next month. Williams joined the team on a two-way deal while Harper Jr. signed an Exhibit 10, training camp contract on Saturday. HoopsHype’s Michael Scotto first reported both signings.

Boston drafted Williams, 23, out of Kentucky No. 46 overall in June after trading back from No. 32 with Orlando. He becomes the fifth center on the roster alongside Neemias Queta, Chris Boucher, Luka Garza and Xavier Tillman Sr., though he’s expected to begin the year developing in Maine. Williams averaged 6.2 points, 5.0 rebounds, 1.8 assists and 0.5 blocks per game for Boston in Summer League, shooting 44.4% from the field and committing two turnovers per game. At the moment, he’s a passing center with a massive frame who’s

He needed to wait to sign until the Celtics finished more roster shuffling earlier this month, trading Georges Niang for two-way rookie wing RJ Luis Jr., who slid into the team’s third and final two-way slot at the time. Boston had already signed Miles Norris to a two-year, two way contract last season before agreeing to one with No. 57 overall pick Max Shulga. The Celtic soon waived Norris, who shot well from three in Maine last season and appeared in his first NBA games late in the season, to clear a spot for Williams.

Ron Harper Jr., 25, also played with the Maine Celtics last year in his comeback season from major shoulder surgery. He participated in Summer League in 2024 and earned a training camp invite. Harper averaged 6.8 PPG, shot 40% FG and 30.8% 3PT in Vegas before shooting 0-for-3 in 11 preseason minutes. His strong start with Maine (14.1 PPG, 39.2% 3PT, 14 G) earned him a two-way contract with the Detroit Pistons, who he finished the season with. There, he shot 38.3% from three on 8.3 attempts per game in the G-League over 23 games. Harper Jr. is the older brother of Spurs guard Dylan Harper, the No. 2 overall pick from this year’s NBA Draft.

He joins rookies Aaron Scott and Hayden Gray, who participated in Summer League for Boston this year, along with former Suns wing Jalen Bridges as training camp invites for the Celtics this fall. All will likely join Shulga, Williams and Luis in Maine after training camp, though Boston has one standard contract available.