Barbosa might be one of the last players on the roster that I would trade. He's amazing insurance at a minimum price tag, and has played well nearly every time he is given a chance. He can't bring anything back at his salary and is a perfect guy to have on the roster in case one of the guards gets hurt (or suspended, for that matter). He can score and get to the rack. Why would we trade him?
I'm not sure why he wants to be on the roster, but the Celtics should be excited to have him for sure. Remember Marquis last year playing pivotal minutes out of nowhere? There's no 12th man in the league better than Barbosa.