As I have reported for the majority of the offseason, Marcus Smart will in fact be coming off of the bench this year. He actually volunteered for the spot after seeing Brad Stevens struggle to make a decision.
If he doesn't, they have no true leader off the bench. Think about it... how can Rozier, Brown, or Tatum be leaders? They have not really been exposed to the bright light yet. Smart has the attitude and the talent.
This makes sense in plenty of different ways. Smart is now able to lead the second unit and Brown is able to grow as a player in the starting lineup.
Smart is best at being this bulldog-like, energy-boosting type player. Now, I expect his offensive game has gotten better, yes. But a t the same time he really is best fitted in that bench role, whether or not he is a better scorer now.
Do not view this as a negative. View it as Smart knowing what needs to happen for this team to be at their best. This is one of many examples to come of Marcus Smart's leadership ability.