Despite the lack of centers, both players are long shots to make the Wizards roster because it is already at the 15-man limit and the team plans to utilize more small-ball lineups this season.
Harrellson, 26, will reunite with John Wall, a teammate at Kentucky during the 2009-10 season. He last played in the NBA during the 2013-14 campaign, when he appeared in 32 games for the Detroit Pistons after spending his first two years with the New York Knicks and Miami Heat.
The 6-foot-10 Harrellson, a 34.7 percent career three-point shooter at the NBA level, spent last season playing in China and Puerto Rico before suiting up for the Phoenix Suns’ summer league team in Las Vegas in July.
Roberts, a 7-footer who went undrafted out of UNC-Asheville in June, played on the Wizards’ summer league team. He logged just seven minutes in three of Washington’s six games.
The two players join point guard Ish Smith and combo guard Toure’ Murry as Washington’s training camp invites.