I don't think this has been mentioned, but i believe the best comparison for Jabari is Shaun Livingston. Shaun was a #4 pick, superstar in the making, and then injuries took away his explosiveness. He reinvented himself and became an integral, yet non-star, for the Warriors.
That is what Jabari needs to do. I would love to see him replicate the Shaun Livingston model. He'd need to focus on his three point shot for this to become a reality, IMO.
I hope he ends with the Celtics for the next decade and retires a champion.