JR definitely has value. Everyone knows he plays well with a new contract looming. Add to that the fact that he's an expiring contract, and we'll have no problem getting value in return.
Do you care to make a wager on that? No one is giving up value for JR. That is patently absurd. He was basically out of the league before LeBron came and saved him. Cavs didn't even want to pay him, LeBron insisted on it. He wouldn't get squat on the free agent market.