Poeltl (back) has been downgraded to doubtful for Saturday's game against the Celtics, Blake Murphy of Sportsnet.ca reports.
Poeltl was held out of Thursday's win over the Bucks while managing a back injury. He was initially tagged as questionable for Saturday's game, but it appears the veteran center will be held out of the front end of the Raptors' back-to-back set. Assuming Poeltl is ruled out, Sandro Mamukelashvili would likely start at center for a second consecutive game (and fourth time this season).