Boston's center, who has been slowed by injuries this year, struggled with his fellow starters Sunday in a loss at Oklahoma City.

The Celtics acknowledged the talent of the Thunder after the game, praising how they played. Celtics center Kristaps Porzingis didn't shy away from the challenge of playing a team

Another Celtics star remained sidelined, however. Jaylen Brown missed his second straight game with a right shoulder sprain. Al Horford also sat out for rest purposes on the second night of a back-to-back.