BOSTON — A couple hours before the Warriors boarded a flight to Boston in early November 2017, Steve Kerr let out a quick quote that had already spread across the Boston sports landscape by the time they landed. He called the Celtics the “team of the future in the East.”



The opinions of these Warriors — multi-time champs loaded with candid, famous voices — carry weight. So, in a conference still inhabited by LeBron James, this Kerr soundbite about an unproven young team turned some heads.



Fourteen months later, as the Warriors return for their annual trip to Boston and the future Kerr predicted is closer to the present, he was reminded of that comment.



“I remember that,” Kerr told The Athletic, before pondering why he said it. “They’d just done such a good job of building their team with picks and young players. And you knew Cleveland was on the way out.”



He paused to rethink his...