We have already clearly seen from last season that Green excels when he is playing major minutes in a starting role.
His 'let the game time to me' style of offense just doesn't suit the role of a limited-minutes-off-the-bench type player.
Last season Green's scoring numbers were exceptional in games during which he started and played 30+ minutes. Games in which he playd <30 minutes off the bench his production was unspectacular.
Green is also one of the few players on this team who doesn't really NEED to prove himself in preseason. Most of the guys on this team are either very young and/or inexperienced (Sully, Olynyk, Bradley, Brooks, Faverani, etc) or are good veterans coming off very poor seasons (Wallace, Hump, etc).
With Rondo out Green is basically the only guy who has already proven himself last season. Preseason is usually a time for coaches to analyse the new additions and young talent of a team, so I don't think we will see much of Green until the regular season starts and he is starting with significant minutes. I would not personally judge him based on his preseason showing.
As for 'real' NBA players, Jordan Crawford and Marshon Brooks have booth been pleasant surprises in the preseason so far. Crawford has handled the Combo-guard role very well and shot super efficient so far, while Brooks is actually leading the team in Pts+Reb+Ass Per 36 minutes so far in the preseason.
Olynyk and Sullinger have both been pretty solid, while Wallace has been fantastic. Bradley has been pretty solid and is hitting his three point shots again.
I think this team is going to be a pretty bad one record wise, but I think a lot of players on this team are going to surprise us regardless.