WALTHAM -- The Celtics are expected to have an open roster spot as coach Doc Rivers said Tuesday after practice that Darko Milicic is not expected to return to the team after attending to his ill mother in Serbia.

Milicic, expected to serve as the primary backup to Kevin Garnett at center, has played just five minutes this season and left the team before Sunday’s game against the Detroit Pistons to spend time with his mother. Rivers said he saw an immediate change in Milicic’s disposition when he found out the news about his mother and doesn’t expect the former lottery pick back.