Simmons suffered a right ankle sprain during Monday's game against the Cavaliers and won't return, Jessica Camerato of NBC Sports Philadelphia reports.
Simmons had dealt with a sore elbow prior to the game, so this isn't any sort of aggravation to the injury he was dealing with previously. Still, the exact severity of the sprain remains unclear at this point in time and Simmons will likely undergo additional tests following the game to make sure there's nothing more serious at hand. Simmons finished Monday's contest with 10 points (5-11 FG), eight rebounds, two assists, three steals and four turnovers across 35 minutes.