Allen attended the morning shootaround but didn't feel well, so coach Doc Rivers decided to leave him back at the hotel for Friday night's game. The Celtics hope Allen will be able to play Sunday at Toronto.
Boston is also missing star forward Kevin Garnett, who'll sit out his fourth straight game with a hyper-extended right knee. But the Celtics do have guard Eddie House, who missed the last game against Miami with the same sort of illness Allen has now.