According to Adrian Wojnarowksi of Yahoo! Sports, Sullinger will need surgery and is out for the rest of the year.
Woj breaks the news and our hearts.
There hasn't been official word of what type of surgery Sully needs or what the timetable might be, but considering Dwight Howard's recovery last season, he could be looking at six months. Howard had surgery on April 20th and was in his first preseason game by October 21st. Again, back injuries are difficult to predict and we don't exactly know the nature and severity of Jared's problem, but there is a possibility that he could be back with Rondo by training camp next year.
There's no easy way to say it. This sucks. Outside of Avery Bradley (who's dealt with career-threatening injuries as well), there hasn't been a rookie that perfectly epitomized what being a Celtic was all about. You got a sense that Sully's work ethic on the glass revved up the veterans like AB's full court defense. He understands what the grit and grind is all about and he's been a sponge with KG as his mentor. He never backed down in the biggest games and stood up to opposing veterans when games turned into bar fights. Get well, big fella.