ESPN's Adrian Wojnarowski reported it first, noting the injury was being called a sprain but was still under scrutiny.
Getting Irving healthy for an impending playoff run is Boston's main priority and its not going to throw caution to the wind as a response to the staggering quantity of maladies that have recently befallen its roster.
Joining him on the bench will be shooting guard Jaylen Brown (concussion), forward Gordon Hayward, hybrid guard Marcus Smart, and forward Daniel Theis - the last three in risk of missing the remainder of the season.
Smart injured his thumb during the Celtics' loss the Indiana Pacers on Sunday night (Monday, PHL time). Initially, there were differing reports about the nature and severity of the injury, as well as how long Smart might be sidelined because of it.
The Celtics hobbled through with a 6-5 record during that stretch, testament to how much they will miss Smart again, and with only 15 games left in the regular season.
Smart is averaging 10.2 points, 4.8 assists and 3.5 rebounds in 29.9 minutes this season.
The Celtics have succeeded this season despite some notable injuries.