Allen is contemplating whether to return for his 19th season or retire
Singleton, a former first-round pick, saw his playing time dwindle with the Wizards last season.
Wizards forwards earned first-team recognition at the Las Vegas summer league last month
The rugged forward-center joins a crowded front court after finding fun in basketball again in the playoffs with the Mavericks last season.
Humphries credits his only season with the Celtics for improved efficiency.
Harrington was option to fill out the Wizards' roster, but decides to go overseas
Final roster spot could go to Al Harrington or remain open.
Kidd, who coached Pierce in Brooklyn last season, says Wizards are "going to be one of the top teams in the East."
Washington further bolsters its front court with a deal for the burly forward.
Veteran forward inks one-year contract to remain with Wizards after joining team midway through last season.