Drummond (toe) has been ruled out for Sunday's game against the Celtics, Adam Aaronson of PhillyVoice.com reports.
Drummond has been downgraded from questionable to out and will miss a sixth straight game. With Joel Embiid (knee) also sidelined, Guerschon Yabusele will likely draw another start at center. Drummond's next chance to suit up will come Tuesday against Dallas.