What happened: Boston traded Jaylen Brown to the Philadelphia 76ers for Paul George and four draft picks. The Celtics also added Mitchell Robinson and Mike Conley, while Philadelphia signed LeBron James.

Why it matters: The moves give Boston a three-year direction after its first-round collapse against Philadelphia. The defending champion New York Knicks and the retooled 76ers leave little margin atop the East.

What to watch: Training camp opens in October, when Boston can begin defining roles for its veteran additions. Their fit will determine whether the reset produces another championship run.