Danny Ainge understands what he has with Jeff Green. He's a guy who can give you 15 points a game as a 3rd option (he's done it). He's a guy who could give you 19 points a game as a 2nd or 1st option (he dropped 20+ consistently when Durant was out). He's a guy who if he's backing up your 2nd best player and only getting 24 minutes off the bench, can give you double digits off the bench (both his seasons in Boston).
Danny was militant in keeping Jeff Green, because he's a solid asset to have. Very capable player. He's young enough that he has another 6+ years where he can be a solid starter/trade asset. Paul Pierce has only a couple years left in him. You don't just let a guy like Jeff Green leave for nothing. Green absolutely will be starting at some point in the future... it could be as soon as next week if Paul PIerce is moved... or later this season if Pierce gets injured. Or next year if Pierce retires. Or two years from now. But the fact is, Jeff Green is a starter who temporarily has a limited role and we have him locked up until 2015... there is plenty of time for him to prove his actual worth either as a Celtic or a trade asset.
You really can't be disappointed in how Jeff Green is playing. Paul Pierce is averaging 18 points in 34 minutes as our #1 option. If you took away 10 of PIerce's minutes, made him the 6th option and had him come off the bench backing up Jeff Green, you wouldn't expect him to drop 20 a night either. That's foolish.