No. Too much locker room upheaval. All perceived leaders would have to immediately defer to Pierce because of what he's done for the franchise, only to try to revert back after he retires in a year or two. On a title contender with mutual respect that may fly, and it would even have worked if Pierce was while we acquired the players, but now, it's too late.
The Celtics are establishing a culture as the team grows up together, and adding a franchise legend like Pierce, while a unique, tempting opportunity, would disrupt the delicate balance that is being built upon.