It's probably a stretch to call this a "rumor", mostly because I haven't seen anybody credible reporting this. Still, feel free to discuss the possibility:
Boston Celtics Interested In Matt Barnes - RantSports.com
The NBA rumors are again taking on a Boston Celtics flavor. During a recent interview Los Angeles Lakers free agent small forward Matt Barnes let the world know that he is a free agent and talking to a few other teams besides the Lakers. One of the NBA teams rumored to be in the mix for Barnes services are the Boston Celtics.
I don't buy this, not even a little bit. There's been some speculation that the Lakers may have moved on from Barnes, but I haven't seen a credible source linking him to the Celts. It would make sense for the team, though, as it would give a more proven bench player than Kris Joseph or Dionte Christmas. Plus, the Celtics have showed interest in Barnes in the past.
Barnes has playoff experience, he can hit the occasional outside shot, he's played good defense in the past, and he's the type of guy who gets under opponents' skin. While I'm not putting any stock in this report, Barnes could make sense here.