BOSTON (CBS) — The Celtics will be without starting center Daniel Theis on Monday night when they welcome the Chicago Bulls to Boston. But the C’s will get another big body back for their front court in Vincent Poirier.

Theis has been downgraded to out for Monday night’s game due to right knee soreness. He’s been Boston’s starting center in 33 of the 34 games that’s he appeared in this season, averaging 7.4 points and 6.0 rebounds while playing some sound defense.

With Theis sidelined Monday night, Brad Stevens will likely turn to big man Enes Kanter in his starting five. Kanter has been playing some stellar ball off the Boston bench lately, averaging 11.7 points and 11.1 rebounds over his last 10 games. He’s pulled down double digit rebounds in six of his last seven games, capped off with a 22-point, 19-rebound explosion in Saturday night’s win over the New Orleans Pelicans.

Poirier has been sidelined for the last month after he underwent surgery to repair a fracture in his right pinkie. Though he’s only played in nine games for the Celtics, the French big man has become a fan favorite for his stylish outfits on the bench. (His “Sex Pants” nickname probably helps, too.) With Theis and Robert Williams III (hip) both out, the 7-footer should get some run against the Bulls on Monday night, giving Stevens a good feel for what he can get out of the big man the rest of the season.