It may seem odd hearing about Jared Sullinger having a breakout season for the Boston Celtics because he is already established as one of their best players.
Before his injury, Sullinger was the leading contributor on the team and was the player that they leaned on the most. He posted 13.3 pointer per game and 7.6 rebounds per game. The Celtics did not have another starter that averaged 13 points per game (of course, there was also Thomas who averaged 19 points coming off the bench).
A lot of people may think Sullinger is actually on his way out because of how well the Celtics did with him injured and that is amplified by all the issues surrounding his conditioning.