I still believe (hope?) that BOS will not trade Brown just to trade him. Trading Brown for Giannis would have made the team better (at least in my opinion). There are other trades that could be done that would result in BOS being better, or at least no worse. It take two to tango though and right now, it does not seem like other teams willing to make a fair trade for him.
I think the market will evolve but right now, I am leaning that Brown starts the season in BOS. I get there is some tension but I think Brown will get over it if needed. So yes, I think there is plenty of chance that Brown starts the season in BOS. He may not finish the season, that is a different question.