I wouldn't be shocked if KJo never played an NBA minute in green.
I they re-sign Jeff Green and bring back Dreads...where would KJo fit in? At the 2 behind Avery Bradley if Ray Allen leaves? I imagine they would sign Jason Terry to fill that void. No room at the Inn for Kjo.
Well, let's start with Green. Didn't he have heart surgery? And hasn't he spent an entire year not playing a dime of basketball? I don't think he's joining the Celts summer development camp, which Joseph will be part of through the end of July. So nice player, but he still has some health issues.
Next, the Ray Allen saga continues -- he's actively shopping and has expressed doubts about wether getting the "band" back together is the right move for him. Personally, I don't think he's worth his contract, but thats another story. If he returns AND they wind up signing Terry AND Green makes a miraculous recovery, they'll probably wind up parking KJ temporarily (until something else changes).
As to Terry, rumors are that the celts offered him a three year deal (15m) via an MLE, and he's giving the Mavs a chance to match the offer. He's not in Allen's shooting class, but he can get on a roll from 3 and give the celtics much needed outside scoring. But he's a defensive liability and doesn't have the all-around shooting/slash game that KJ has (IF he develops to an NBA level).
Further, if you read my post, I said, "if he [KJ] sticks"... No doubt he's a bit of a project, but the Celts signed him (terms undisclosed) and will try to develop him. That will include the summer training camp and then, who knows. Maybe he sees some time at the 2 or 3 while Green recovers his skills, maybe they park him in Maine to work on his defense. Lots of possibilities... but to say he'll never sniff the NBA is a bit premature (not saying that was your post).
Right now, he's making 700k and is willing to learn. So keep your head up, KJ, and play your butt off and good things might happen.